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Message-ID: <20180904121503.GF13888@piout.net>
Date: Tue, 4 Sep 2018 14:15:03 +0200
From: Alexandre Belloni <alexandre.belloni@...tlin.com>
To: Linus Walleij <linus.walleij@...aro.org>
Cc: Mark Brown <broonie@...nel.org>, linux-spi@...r.kernel.org,
linux-gpio@...r.kernel.org,
Haavard Skinnemoen <hskinnemoen@...il.com>,
Nicolas Ferre <nicolas.ferre@...rochip.com>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] spi: Delete Atmel AT91 SPI driver
On 04/09/2018 11:49:22+0200, Linus Walleij wrote:
> This driver depends on the deleted AT91 architecture and cause
> me headaches from a GPIO point of view. It is unused so delete
> it.
>
While AVR32 is gone, AT91 is alive and well.
Also, get_maintainers is correct (for once):
Nicolas Ferre <nicolas.ferre@...rochip.com> (supporter:ATMEL SPI DRIVER)
Alexandre Belloni <alexandre.belloni@...tlin.com> (supporter:ARM/Microchip (AT91) SoC support)
linux-arm-kernel@...ts.infradead.org (moderated list:ARM/Microchip (AT91) SoC support)
> Cc: Haavard Skinnemoen <hskinnemoen@...il.com>
> Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
> ---
> drivers/spi/Kconfig | 7 -
> drivers/spi/Makefile | 1 -
> drivers/spi/spi-atmel.c | 1843 ---------------------------------------
> 3 files changed, 1851 deletions(-)
> delete mode 100644 drivers/spi/spi-atmel.c
>
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index 671d078349cc..6624f43268d2 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -76,13 +76,6 @@ config SPI_ARMADA_3700
> This enables support for the SPI controller present on the
> Marvell Armada 3700 SoCs.
>
> -config SPI_ATMEL
> - tristate "Atmel SPI Controller"
> - depends on ARCH_AT91 || COMPILE_TEST
> - help
> - This selects a driver for the Atmel SPI Controller, present on
> - many AT91 ARM chips.
> -
> config SPI_AU1550
> tristate "Au1550/Au1200/Au1300 SPI Controller"
> depends on MIPS_ALCHEMY
> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> index a90d55970036..088cc3f5616f 100644
> --- a/drivers/spi/Makefile
> +++ b/drivers/spi/Makefile
> @@ -15,7 +15,6 @@ obj-$(CONFIG_SPI_LOOPBACK_TEST) += spi-loopback-test.o
> # SPI master controller drivers (bus)
> obj-$(CONFIG_SPI_ALTERA) += spi-altera.o
> obj-$(CONFIG_SPI_ARMADA_3700) += spi-armada-3700.o
> -obj-$(CONFIG_SPI_ATMEL) += spi-atmel.o
> obj-$(CONFIG_SPI_ATH79) += spi-ath79.o
> obj-$(CONFIG_SPI_AU1550) += spi-au1550.o
> obj-$(CONFIG_SPI_AXI_SPI_ENGINE) += spi-axi-spi-engine.o
> diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
> deleted file mode 100644
> index 3f890d162934..000000000000
> --- a/drivers/spi/spi-atmel.c
> +++ /dev/null
> @@ -1,1843 +0,0 @@
> -/*
> - * Driver for Atmel AT32 and AT91 SPI Controllers
> - *
> - * Copyright (C) 2006 Atmel Corporation
> - *
> - * This program is free software; you can redistribute it and/or modify
> - * it under the terms of the GNU General Public License version 2 as
> - * published by the Free Software Foundation.
> - */
> -
> -#include <linux/kernel.h>
> -#include <linux/clk.h>
> -#include <linux/module.h>
> -#include <linux/platform_device.h>
> -#include <linux/delay.h>
> -#include <linux/dma-mapping.h>
> -#include <linux/dmaengine.h>
> -#include <linux/err.h>
> -#include <linux/interrupt.h>
> -#include <linux/spi/spi.h>
> -#include <linux/slab.h>
> -#include <linux/platform_data/dma-atmel.h>
> -#include <linux/of.h>
> -
> -#include <linux/io.h>
> -#include <linux/gpio.h>
> -#include <linux/of_gpio.h>
> -#include <linux/pinctrl/consumer.h>
> -#include <linux/pm_runtime.h>
> -
> -/* SPI register offsets */
> -#define SPI_CR 0x0000
> -#define SPI_MR 0x0004
> -#define SPI_RDR 0x0008
> -#define SPI_TDR 0x000c
> -#define SPI_SR 0x0010
> -#define SPI_IER 0x0014
> -#define SPI_IDR 0x0018
> -#define SPI_IMR 0x001c
> -#define SPI_CSR0 0x0030
> -#define SPI_CSR1 0x0034
> -#define SPI_CSR2 0x0038
> -#define SPI_CSR3 0x003c
> -#define SPI_FMR 0x0040
> -#define SPI_FLR 0x0044
> -#define SPI_VERSION 0x00fc
> -#define SPI_RPR 0x0100
> -#define SPI_RCR 0x0104
> -#define SPI_TPR 0x0108
> -#define SPI_TCR 0x010c
> -#define SPI_RNPR 0x0110
> -#define SPI_RNCR 0x0114
> -#define SPI_TNPR 0x0118
> -#define SPI_TNCR 0x011c
> -#define SPI_PTCR 0x0120
> -#define SPI_PTSR 0x0124
> -
> -/* Bitfields in CR */
> -#define SPI_SPIEN_OFFSET 0
> -#define SPI_SPIEN_SIZE 1
> -#define SPI_SPIDIS_OFFSET 1
> -#define SPI_SPIDIS_SIZE 1
> -#define SPI_SWRST_OFFSET 7
> -#define SPI_SWRST_SIZE 1
> -#define SPI_LASTXFER_OFFSET 24
> -#define SPI_LASTXFER_SIZE 1
> -#define SPI_TXFCLR_OFFSET 16
> -#define SPI_TXFCLR_SIZE 1
> -#define SPI_RXFCLR_OFFSET 17
> -#define SPI_RXFCLR_SIZE 1
> -#define SPI_FIFOEN_OFFSET 30
> -#define SPI_FIFOEN_SIZE 1
> -#define SPI_FIFODIS_OFFSET 31
> -#define SPI_FIFODIS_SIZE 1
> -
> -/* Bitfields in MR */
> -#define SPI_MSTR_OFFSET 0
> -#define SPI_MSTR_SIZE 1
> -#define SPI_PS_OFFSET 1
> -#define SPI_PS_SIZE 1
> -#define SPI_PCSDEC_OFFSET 2
> -#define SPI_PCSDEC_SIZE 1
> -#define SPI_FDIV_OFFSET 3
> -#define SPI_FDIV_SIZE 1
> -#define SPI_MODFDIS_OFFSET 4
> -#define SPI_MODFDIS_SIZE 1
> -#define SPI_WDRBT_OFFSET 5
> -#define SPI_WDRBT_SIZE 1
> -#define SPI_LLB_OFFSET 7
> -#define SPI_LLB_SIZE 1
> -#define SPI_PCS_OFFSET 16
> -#define SPI_PCS_SIZE 4
> -#define SPI_DLYBCS_OFFSET 24
> -#define SPI_DLYBCS_SIZE 8
> -
> -/* Bitfields in RDR */
> -#define SPI_RD_OFFSET 0
> -#define SPI_RD_SIZE 16
> -
> -/* Bitfields in TDR */
> -#define SPI_TD_OFFSET 0
> -#define SPI_TD_SIZE 16
> -
> -/* Bitfields in SR */
> -#define SPI_RDRF_OFFSET 0
> -#define SPI_RDRF_SIZE 1
> -#define SPI_TDRE_OFFSET 1
> -#define SPI_TDRE_SIZE 1
> -#define SPI_MODF_OFFSET 2
> -#define SPI_MODF_SIZE 1
> -#define SPI_OVRES_OFFSET 3
> -#define SPI_OVRES_SIZE 1
> -#define SPI_ENDRX_OFFSET 4
> -#define SPI_ENDRX_SIZE 1
> -#define SPI_ENDTX_OFFSET 5
> -#define SPI_ENDTX_SIZE 1
> -#define SPI_RXBUFF_OFFSET 6
> -#define SPI_RXBUFF_SIZE 1
> -#define SPI_TXBUFE_OFFSET 7
> -#define SPI_TXBUFE_SIZE 1
> -#define SPI_NSSR_OFFSET 8
> -#define SPI_NSSR_SIZE 1
> -#define SPI_TXEMPTY_OFFSET 9
> -#define SPI_TXEMPTY_SIZE 1
> -#define SPI_SPIENS_OFFSET 16
> -#define SPI_SPIENS_SIZE 1
> -#define SPI_TXFEF_OFFSET 24
> -#define SPI_TXFEF_SIZE 1
> -#define SPI_TXFFF_OFFSET 25
> -#define SPI_TXFFF_SIZE 1
> -#define SPI_TXFTHF_OFFSET 26
> -#define SPI_TXFTHF_SIZE 1
> -#define SPI_RXFEF_OFFSET 27
> -#define SPI_RXFEF_SIZE 1
> -#define SPI_RXFFF_OFFSET 28
> -#define SPI_RXFFF_SIZE 1
> -#define SPI_RXFTHF_OFFSET 29
> -#define SPI_RXFTHF_SIZE 1
> -#define SPI_TXFPTEF_OFFSET 30
> -#define SPI_TXFPTEF_SIZE 1
> -#define SPI_RXFPTEF_OFFSET 31
> -#define SPI_RXFPTEF_SIZE 1
> -
> -/* Bitfields in CSR0 */
> -#define SPI_CPOL_OFFSET 0
> -#define SPI_CPOL_SIZE 1
> -#define SPI_NCPHA_OFFSET 1
> -#define SPI_NCPHA_SIZE 1
> -#define SPI_CSAAT_OFFSET 3
> -#define SPI_CSAAT_SIZE 1
> -#define SPI_BITS_OFFSET 4
> -#define SPI_BITS_SIZE 4
> -#define SPI_SCBR_OFFSET 8
> -#define SPI_SCBR_SIZE 8
> -#define SPI_DLYBS_OFFSET 16
> -#define SPI_DLYBS_SIZE 8
> -#define SPI_DLYBCT_OFFSET 24
> -#define SPI_DLYBCT_SIZE 8
> -
> -/* Bitfields in RCR */
> -#define SPI_RXCTR_OFFSET 0
> -#define SPI_RXCTR_SIZE 16
> -
> -/* Bitfields in TCR */
> -#define SPI_TXCTR_OFFSET 0
> -#define SPI_TXCTR_SIZE 16
> -
> -/* Bitfields in RNCR */
> -#define SPI_RXNCR_OFFSET 0
> -#define SPI_RXNCR_SIZE 16
> -
> -/* Bitfields in TNCR */
> -#define SPI_TXNCR_OFFSET 0
> -#define SPI_TXNCR_SIZE 16
> -
> -/* Bitfields in PTCR */
> -#define SPI_RXTEN_OFFSET 0
> -#define SPI_RXTEN_SIZE 1
> -#define SPI_RXTDIS_OFFSET 1
> -#define SPI_RXTDIS_SIZE 1
> -#define SPI_TXTEN_OFFSET 8
> -#define SPI_TXTEN_SIZE 1
> -#define SPI_TXTDIS_OFFSET 9
> -#define SPI_TXTDIS_SIZE 1
> -
> -/* Bitfields in FMR */
> -#define SPI_TXRDYM_OFFSET 0
> -#define SPI_TXRDYM_SIZE 2
> -#define SPI_RXRDYM_OFFSET 4
> -#define SPI_RXRDYM_SIZE 2
> -#define SPI_TXFTHRES_OFFSET 16
> -#define SPI_TXFTHRES_SIZE 6
> -#define SPI_RXFTHRES_OFFSET 24
> -#define SPI_RXFTHRES_SIZE 6
> -
> -/* Bitfields in FLR */
> -#define SPI_TXFL_OFFSET 0
> -#define SPI_TXFL_SIZE 6
> -#define SPI_RXFL_OFFSET 16
> -#define SPI_RXFL_SIZE 6
> -
> -/* Constants for BITS */
> -#define SPI_BITS_8_BPT 0
> -#define SPI_BITS_9_BPT 1
> -#define SPI_BITS_10_BPT 2
> -#define SPI_BITS_11_BPT 3
> -#define SPI_BITS_12_BPT 4
> -#define SPI_BITS_13_BPT 5
> -#define SPI_BITS_14_BPT 6
> -#define SPI_BITS_15_BPT 7
> -#define SPI_BITS_16_BPT 8
> -#define SPI_ONE_DATA 0
> -#define SPI_TWO_DATA 1
> -#define SPI_FOUR_DATA 2
> -
> -/* Bit manipulation macros */
> -#define SPI_BIT(name) \
> - (1 << SPI_##name##_OFFSET)
> -#define SPI_BF(name, value) \
> - (((value) & ((1 << SPI_##name##_SIZE) - 1)) << SPI_##name##_OFFSET)
> -#define SPI_BFEXT(name, value) \
> - (((value) >> SPI_##name##_OFFSET) & ((1 << SPI_##name##_SIZE) - 1))
> -#define SPI_BFINS(name, value, old) \
> - (((old) & ~(((1 << SPI_##name##_SIZE) - 1) << SPI_##name##_OFFSET)) \
> - | SPI_BF(name, value))
> -
> -/* Register access macros */
> -#ifdef CONFIG_AVR32
> -#define spi_readl(port, reg) \
> - __raw_readl((port)->regs + SPI_##reg)
> -#define spi_writel(port, reg, value) \
> - __raw_writel((value), (port)->regs + SPI_##reg)
> -
> -#define spi_readw(port, reg) \
> - __raw_readw((port)->regs + SPI_##reg)
> -#define spi_writew(port, reg, value) \
> - __raw_writew((value), (port)->regs + SPI_##reg)
> -
> -#define spi_readb(port, reg) \
> - __raw_readb((port)->regs + SPI_##reg)
> -#define spi_writeb(port, reg, value) \
> - __raw_writeb((value), (port)->regs + SPI_##reg)
> -#else
> -#define spi_readl(port, reg) \
> - readl_relaxed((port)->regs + SPI_##reg)
> -#define spi_writel(port, reg, value) \
> - writel_relaxed((value), (port)->regs + SPI_##reg)
> -
> -#define spi_readw(port, reg) \
> - readw_relaxed((port)->regs + SPI_##reg)
> -#define spi_writew(port, reg, value) \
> - writew_relaxed((value), (port)->regs + SPI_##reg)
> -
> -#define spi_readb(port, reg) \
> - readb_relaxed((port)->regs + SPI_##reg)
> -#define spi_writeb(port, reg, value) \
> - writeb_relaxed((value), (port)->regs + SPI_##reg)
> -#endif
> -/* use PIO for small transfers, avoiding DMA setup/teardown overhead and
> - * cache operations; better heuristics consider wordsize and bitrate.
> - */
> -#define DMA_MIN_BYTES 16
> -
> -#define SPI_DMA_TIMEOUT (msecs_to_jiffies(1000))
> -
> -#define AUTOSUSPEND_TIMEOUT 2000
> -
> -struct atmel_spi_caps {
> - bool is_spi2;
> - bool has_wdrbt;
> - bool has_dma_support;
> - bool has_pdc_support;
> -};
> -
> -/*
> - * The core SPI transfer engine just talks to a register bank to set up
> - * DMA transfers; transfer queue progress is driven by IRQs. The clock
> - * framework provides the base clock, subdivided for each spi_device.
> - */
> -struct atmel_spi {
> - spinlock_t lock;
> - unsigned long flags;
> -
> - phys_addr_t phybase;
> - void __iomem *regs;
> - int irq;
> - struct clk *clk;
> - struct platform_device *pdev;
> - unsigned long spi_clk;
> -
> - struct spi_transfer *current_transfer;
> - int current_remaining_bytes;
> - int done_status;
> - dma_addr_t dma_addr_rx_bbuf;
> - dma_addr_t dma_addr_tx_bbuf;
> - void *addr_rx_bbuf;
> - void *addr_tx_bbuf;
> -
> - struct completion xfer_completion;
> -
> - struct atmel_spi_caps caps;
> -
> - bool use_dma;
> - bool use_pdc;
> - bool use_cs_gpios;
> -
> - bool keep_cs;
> - bool cs_active;
> -
> - u32 fifo_size;
> -};
> -
> -/* Controller-specific per-slave state */
> -struct atmel_spi_device {
> - unsigned int npcs_pin;
> - u32 csr;
> -};
> -
> -#define SPI_MAX_DMA_XFER 65535 /* true for both PDC and DMA */
> -#define INVALID_DMA_ADDRESS 0xffffffff
> -
> -/*
> - * Version 2 of the SPI controller has
> - * - CR.LASTXFER
> - * - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
> - * - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
> - * - SPI_CSRx.CSAAT
> - * - SPI_CSRx.SBCR allows faster clocking
> - */
> -static bool atmel_spi_is_v2(struct atmel_spi *as)
> -{
> - return as->caps.is_spi2;
> -}
> -
> -/*
> - * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
> - * they assume that spi slave device state will not change on deselect, so
> - * that automagic deselection is OK. ("NPCSx rises if no data is to be
> - * transmitted") Not so! Workaround uses nCSx pins as GPIOs; or newer
> - * controllers have CSAAT and friends.
> - *
> - * Since the CSAAT functionality is a bit weird on newer controllers as
> - * well, we use GPIO to control nCSx pins on all controllers, updating
> - * MR.PCS to avoid confusing the controller. Using GPIOs also lets us
> - * support active-high chipselects despite the controller's belief that
> - * only active-low devices/systems exists.
> - *
> - * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
> - * right when driven with GPIO. ("Mode Fault does not allow more than one
> - * Master on Chip Select 0.") No workaround exists for that ... so for
> - * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
> - * and (c) will trigger that first erratum in some cases.
> - */
> -
> -static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
> -{
> - struct atmel_spi_device *asd = spi->controller_state;
> - unsigned active = spi->mode & SPI_CS_HIGH;
> - u32 mr;
> -
> - if (atmel_spi_is_v2(as)) {
> - spi_writel(as, CSR0 + 4 * spi->chip_select, asd->csr);
> - /* For the low SPI version, there is a issue that PDC transfer
> - * on CS1,2,3 needs SPI_CSR0.BITS config as SPI_CSR1,2,3.BITS
> - */
> - spi_writel(as, CSR0, asd->csr);
> - if (as->caps.has_wdrbt) {
> - spi_writel(as, MR,
> - SPI_BF(PCS, ~(0x01 << spi->chip_select))
> - | SPI_BIT(WDRBT)
> - | SPI_BIT(MODFDIS)
> - | SPI_BIT(MSTR));
> - } else {
> - spi_writel(as, MR,
> - SPI_BF(PCS, ~(0x01 << spi->chip_select))
> - | SPI_BIT(MODFDIS)
> - | SPI_BIT(MSTR));
> - }
> -
> - mr = spi_readl(as, MR);
> - if (as->use_cs_gpios)
> - gpio_set_value(asd->npcs_pin, active);
> - } else {
> - u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
> - int i;
> - u32 csr;
> -
> - /* Make sure clock polarity is correct */
> - for (i = 0; i < spi->master->num_chipselect; i++) {
> - csr = spi_readl(as, CSR0 + 4 * i);
> - if ((csr ^ cpol) & SPI_BIT(CPOL))
> - spi_writel(as, CSR0 + 4 * i,
> - csr ^ SPI_BIT(CPOL));
> - }
> -
> - mr = spi_readl(as, MR);
> - mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
> - if (as->use_cs_gpios && spi->chip_select != 0)
> - gpio_set_value(asd->npcs_pin, active);
> - spi_writel(as, MR, mr);
> - }
> -
> - dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
> - asd->npcs_pin, active ? " (high)" : "",
> - mr);
> -}
> -
> -static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
> -{
> - struct atmel_spi_device *asd = spi->controller_state;
> - unsigned active = spi->mode & SPI_CS_HIGH;
> - u32 mr;
> -
> - /* only deactivate *this* device; sometimes transfers to
> - * another device may be active when this routine is called.
> - */
> - mr = spi_readl(as, MR);
> - if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
> - mr = SPI_BFINS(PCS, 0xf, mr);
> - spi_writel(as, MR, mr);
> - }
> -
> - dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
> - asd->npcs_pin, active ? " (low)" : "",
> - mr);
> -
> - if (!as->use_cs_gpios)
> - spi_writel(as, CR, SPI_BIT(LASTXFER));
> - else if (atmel_spi_is_v2(as) || spi->chip_select != 0)
> - gpio_set_value(asd->npcs_pin, !active);
> -}
> -
> -static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock)
> -{
> - spin_lock_irqsave(&as->lock, as->flags);
> -}
> -
> -static void atmel_spi_unlock(struct atmel_spi *as) __releases(&as->lock)
> -{
> - spin_unlock_irqrestore(&as->lock, as->flags);
> -}
> -
> -static inline bool atmel_spi_is_vmalloc_xfer(struct spi_transfer *xfer)
> -{
> - return is_vmalloc_addr(xfer->tx_buf) || is_vmalloc_addr(xfer->rx_buf);
> -}
> -
> -static inline bool atmel_spi_use_dma(struct atmel_spi *as,
> - struct spi_transfer *xfer)
> -{
> - return as->use_dma && xfer->len >= DMA_MIN_BYTES;
> -}
> -
> -static bool atmel_spi_can_dma(struct spi_master *master,
> - struct spi_device *spi,
> - struct spi_transfer *xfer)
> -{
> - struct atmel_spi *as = spi_master_get_devdata(master);
> -
> - if (IS_ENABLED(CONFIG_SOC_SAM_V4_V5))
> - return atmel_spi_use_dma(as, xfer) &&
> - !atmel_spi_is_vmalloc_xfer(xfer);
> - else
> - return atmel_spi_use_dma(as, xfer);
> -
> -}
> -
> -static int atmel_spi_dma_slave_config(struct atmel_spi *as,
> - struct dma_slave_config *slave_config,
> - u8 bits_per_word)
> -{
> - struct spi_master *master = platform_get_drvdata(as->pdev);
> - int err = 0;
> -
> - if (bits_per_word > 8) {
> - slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
> - slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
> - } else {
> - slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> - slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> - }
> -
> - slave_config->dst_addr = (dma_addr_t)as->phybase + SPI_TDR;
> - slave_config->src_addr = (dma_addr_t)as->phybase + SPI_RDR;
> - slave_config->src_maxburst = 1;
> - slave_config->dst_maxburst = 1;
> - slave_config->device_fc = false;
> -
> - /*
> - * This driver uses fixed peripheral select mode (PS bit set to '0' in
> - * the Mode Register).
> - * So according to the datasheet, when FIFOs are available (and
> - * enabled), the Transmit FIFO operates in Multiple Data Mode.
> - * In this mode, up to 2 data, not 4, can be written into the Transmit
> - * Data Register in a single access.
> - * However, the first data has to be written into the lowest 16 bits and
> - * the second data into the highest 16 bits of the Transmit
> - * Data Register. For 8bit data (the most frequent case), it would
> - * require to rework tx_buf so each data would actualy fit 16 bits.
> - * So we'd rather write only one data at the time. Hence the transmit
> - * path works the same whether FIFOs are available (and enabled) or not.
> - */
> - slave_config->direction = DMA_MEM_TO_DEV;
> - if (dmaengine_slave_config(master->dma_tx, slave_config)) {
> - dev_err(&as->pdev->dev,
> - "failed to configure tx dma channel\n");
> - err = -EINVAL;
> - }
> -
> - /*
> - * This driver configures the spi controller for master mode (MSTR bit
> - * set to '1' in the Mode Register).
> - * So according to the datasheet, when FIFOs are available (and
> - * enabled), the Receive FIFO operates in Single Data Mode.
> - * So the receive path works the same whether FIFOs are available (and
> - * enabled) or not.
> - */
> - slave_config->direction = DMA_DEV_TO_MEM;
> - if (dmaengine_slave_config(master->dma_rx, slave_config)) {
> - dev_err(&as->pdev->dev,
> - "failed to configure rx dma channel\n");
> - err = -EINVAL;
> - }
> -
> - return err;
> -}
> -
> -static int atmel_spi_configure_dma(struct spi_master *master,
> - struct atmel_spi *as)
> -{
> - struct dma_slave_config slave_config;
> - struct device *dev = &as->pdev->dev;
> - int err;
> -
> - dma_cap_mask_t mask;
> - dma_cap_zero(mask);
> - dma_cap_set(DMA_SLAVE, mask);
> -
> - master->dma_tx = dma_request_slave_channel_reason(dev, "tx");
> - if (IS_ERR(master->dma_tx)) {
> - err = PTR_ERR(master->dma_tx);
> - if (err == -EPROBE_DEFER) {
> - dev_warn(dev, "no DMA channel available at the moment\n");
> - goto error_clear;
> - }
> - dev_err(dev,
> - "DMA TX channel not available, SPI unable to use DMA\n");
> - err = -EBUSY;
> - goto error_clear;
> - }
> -
> - /*
> - * No reason to check EPROBE_DEFER here since we have already requested
> - * tx channel. If it fails here, it's for another reason.
> - */
> - master->dma_rx = dma_request_slave_channel(dev, "rx");
> -
> - if (!master->dma_rx) {
> - dev_err(dev,
> - "DMA RX channel not available, SPI unable to use DMA\n");
> - err = -EBUSY;
> - goto error;
> - }
> -
> - err = atmel_spi_dma_slave_config(as, &slave_config, 8);
> - if (err)
> - goto error;
> -
> - dev_info(&as->pdev->dev,
> - "Using %s (tx) and %s (rx) for DMA transfers\n",
> - dma_chan_name(master->dma_tx),
> - dma_chan_name(master->dma_rx));
> -
> - return 0;
> -error:
> - if (master->dma_rx)
> - dma_release_channel(master->dma_rx);
> - if (!IS_ERR(master->dma_tx))
> - dma_release_channel(master->dma_tx);
> -error_clear:
> - master->dma_tx = master->dma_rx = NULL;
> - return err;
> -}
> -
> -static void atmel_spi_stop_dma(struct spi_master *master)
> -{
> - if (master->dma_rx)
> - dmaengine_terminate_all(master->dma_rx);
> - if (master->dma_tx)
> - dmaengine_terminate_all(master->dma_tx);
> -}
> -
> -static void atmel_spi_release_dma(struct spi_master *master)
> -{
> - if (master->dma_rx) {
> - dma_release_channel(master->dma_rx);
> - master->dma_rx = NULL;
> - }
> - if (master->dma_tx) {
> - dma_release_channel(master->dma_tx);
> - master->dma_tx = NULL;
> - }
> -}
> -
> -/* This function is called by the DMA driver from tasklet context */
> -static void dma_callback(void *data)
> -{
> - struct spi_master *master = data;
> - struct atmel_spi *as = spi_master_get_devdata(master);
> -
> - if (is_vmalloc_addr(as->current_transfer->rx_buf) &&
> - IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
> - memcpy(as->current_transfer->rx_buf, as->addr_rx_bbuf,
> - as->current_transfer->len);
> - }
> - complete(&as->xfer_completion);
> -}
> -
> -/*
> - * Next transfer using PIO without FIFO.
> - */
> -static void atmel_spi_next_xfer_single(struct spi_master *master,
> - struct spi_transfer *xfer)
> -{
> - struct atmel_spi *as = spi_master_get_devdata(master);
> - unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
> -
> - dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_pio\n");
> -
> - /* Make sure data is not remaining in RDR */
> - spi_readl(as, RDR);
> - while (spi_readl(as, SR) & SPI_BIT(RDRF)) {
> - spi_readl(as, RDR);
> - cpu_relax();
> - }
> -
> - if (xfer->bits_per_word > 8)
> - spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
> - else
> - spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));
> -
> - dev_dbg(master->dev.parent,
> - " start pio xfer %p: len %u tx %p rx %p bitpw %d\n",
> - xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
> - xfer->bits_per_word);
> -
> - /* Enable relevant interrupts */
> - spi_writel(as, IER, SPI_BIT(RDRF) | SPI_BIT(OVRES));
> -}
> -
> -/*
> - * Next transfer using PIO with FIFO.
> - */
> -static void atmel_spi_next_xfer_fifo(struct spi_master *master,
> - struct spi_transfer *xfer)
> -{
> - struct atmel_spi *as = spi_master_get_devdata(master);
> - u32 current_remaining_data, num_data;
> - u32 offset = xfer->len - as->current_remaining_bytes;
> - const u16 *words = (const u16 *)((u8 *)xfer->tx_buf + offset);
> - const u8 *bytes = (const u8 *)((u8 *)xfer->tx_buf + offset);
> - u16 td0, td1;
> - u32 fifomr;
> -
> - dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_fifo\n");
> -
> - /* Compute the number of data to transfer in the current iteration */
> - current_remaining_data = ((xfer->bits_per_word > 8) ?
> - ((u32)as->current_remaining_bytes >> 1) :
> - (u32)as->current_remaining_bytes);
> - num_data = min(current_remaining_data, as->fifo_size);
> -
> - /* Flush RX and TX FIFOs */
> - spi_writel(as, CR, SPI_BIT(RXFCLR) | SPI_BIT(TXFCLR));
> - while (spi_readl(as, FLR))
> - cpu_relax();
> -
> - /* Set RX FIFO Threshold to the number of data to transfer */
> - fifomr = spi_readl(as, FMR);
> - spi_writel(as, FMR, SPI_BFINS(RXFTHRES, num_data, fifomr));
> -
> - /* Clear FIFO flags in the Status Register, especially RXFTHF */
> - (void)spi_readl(as, SR);
> -
> - /* Fill TX FIFO */
> - while (num_data >= 2) {
> - if (xfer->bits_per_word > 8) {
> - td0 = *words++;
> - td1 = *words++;
> - } else {
> - td0 = *bytes++;
> - td1 = *bytes++;
> - }
> -
> - spi_writel(as, TDR, (td1 << 16) | td0);
> - num_data -= 2;
> - }
> -
> - if (num_data) {
> - if (xfer->bits_per_word > 8)
> - td0 = *words++;
> - else
> - td0 = *bytes++;
> -
> - spi_writew(as, TDR, td0);
> - num_data--;
> - }
> -
> - dev_dbg(master->dev.parent,
> - " start fifo xfer %p: len %u tx %p rx %p bitpw %d\n",
> - xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
> - xfer->bits_per_word);
> -
> - /*
> - * Enable RX FIFO Threshold Flag interrupt to be notified about
> - * transfer completion.
> - */
> - spi_writel(as, IER, SPI_BIT(RXFTHF) | SPI_BIT(OVRES));
> -}
> -
> -/*
> - * Next transfer using PIO.
> - */
> -static void atmel_spi_next_xfer_pio(struct spi_master *master,
> - struct spi_transfer *xfer)
> -{
> - struct atmel_spi *as = spi_master_get_devdata(master);
> -
> - if (as->fifo_size)
> - atmel_spi_next_xfer_fifo(master, xfer);
> - else
> - atmel_spi_next_xfer_single(master, xfer);
> -}
> -
> -/*
> - * Submit next transfer for DMA.
> - */
> -static int atmel_spi_next_xfer_dma_submit(struct spi_master *master,
> - struct spi_transfer *xfer,
> - u32 *plen)
> -{
> - struct atmel_spi *as = spi_master_get_devdata(master);
> - struct dma_chan *rxchan = master->dma_rx;
> - struct dma_chan *txchan = master->dma_tx;
> - struct dma_async_tx_descriptor *rxdesc;
> - struct dma_async_tx_descriptor *txdesc;
> - struct dma_slave_config slave_config;
> - dma_cookie_t cookie;
> -
> - dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_dma_submit\n");
> -
> - /* Check that the channels are available */
> - if (!rxchan || !txchan)
> - return -ENODEV;
> -
> - /* release lock for DMA operations */
> - atmel_spi_unlock(as);
> -
> - *plen = xfer->len;
> -
> - if (atmel_spi_dma_slave_config(as, &slave_config,
> - xfer->bits_per_word))
> - goto err_exit;
> -
> - /* Send both scatterlists */
> - if (atmel_spi_is_vmalloc_xfer(xfer) &&
> - IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
> - rxdesc = dmaengine_prep_slave_single(rxchan,
> - as->dma_addr_rx_bbuf,
> - xfer->len,
> - DMA_DEV_TO_MEM,
> - DMA_PREP_INTERRUPT |
> - DMA_CTRL_ACK);
> - } else {
> - rxdesc = dmaengine_prep_slave_sg(rxchan,
> - xfer->rx_sg.sgl,
> - xfer->rx_sg.nents,
> - DMA_DEV_TO_MEM,
> - DMA_PREP_INTERRUPT |
> - DMA_CTRL_ACK);
> - }
> - if (!rxdesc)
> - goto err_dma;
> -
> - if (atmel_spi_is_vmalloc_xfer(xfer) &&
> - IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
> - memcpy(as->addr_tx_bbuf, xfer->tx_buf, xfer->len);
> - txdesc = dmaengine_prep_slave_single(txchan,
> - as->dma_addr_tx_bbuf,
> - xfer->len, DMA_MEM_TO_DEV,
> - DMA_PREP_INTERRUPT |
> - DMA_CTRL_ACK);
> - } else {
> - txdesc = dmaengine_prep_slave_sg(txchan,
> - xfer->tx_sg.sgl,
> - xfer->tx_sg.nents,
> - DMA_MEM_TO_DEV,
> - DMA_PREP_INTERRUPT |
> - DMA_CTRL_ACK);
> - }
> - if (!txdesc)
> - goto err_dma;
> -
> - dev_dbg(master->dev.parent,
> - " start dma xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
> - xfer, xfer->len, xfer->tx_buf, (unsigned long long)xfer->tx_dma,
> - xfer->rx_buf, (unsigned long long)xfer->rx_dma);
> -
> - /* Enable relevant interrupts */
> - spi_writel(as, IER, SPI_BIT(OVRES));
> -
> - /* Put the callback on the RX transfer only, that should finish last */
> - rxdesc->callback = dma_callback;
> - rxdesc->callback_param = master;
> -
> - /* Submit and fire RX and TX with TX last so we're ready to read! */
> - cookie = rxdesc->tx_submit(rxdesc);
> - if (dma_submit_error(cookie))
> - goto err_dma;
> - cookie = txdesc->tx_submit(txdesc);
> - if (dma_submit_error(cookie))
> - goto err_dma;
> - rxchan->device->device_issue_pending(rxchan);
> - txchan->device->device_issue_pending(txchan);
> -
> - /* take back lock */
> - atmel_spi_lock(as);
> - return 0;
> -
> -err_dma:
> - spi_writel(as, IDR, SPI_BIT(OVRES));
> - atmel_spi_stop_dma(master);
> -err_exit:
> - atmel_spi_lock(as);
> - return -ENOMEM;
> -}
> -
> -static void atmel_spi_next_xfer_data(struct spi_master *master,
> - struct spi_transfer *xfer,
> - dma_addr_t *tx_dma,
> - dma_addr_t *rx_dma,
> - u32 *plen)
> -{
> - *rx_dma = xfer->rx_dma + xfer->len - *plen;
> - *tx_dma = xfer->tx_dma + xfer->len - *plen;
> - if (*plen > master->max_dma_len)
> - *plen = master->max_dma_len;
> -}
> -
> -static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
> - struct spi_device *spi,
> - struct spi_transfer *xfer)
> -{
> - u32 scbr, csr;
> - unsigned long bus_hz;
> -
> - /* v1 chips start out at half the peripheral bus speed. */
> - bus_hz = as->spi_clk;
> - if (!atmel_spi_is_v2(as))
> - bus_hz /= 2;
> -
> - /*
> - * Calculate the lowest divider that satisfies the
> - * constraint, assuming div32/fdiv/mbz == 0.
> - */
> - scbr = DIV_ROUND_UP(bus_hz, xfer->speed_hz);
> -
> - /*
> - * If the resulting divider doesn't fit into the
> - * register bitfield, we can't satisfy the constraint.
> - */
> - if (scbr >= (1 << SPI_SCBR_SIZE)) {
> - dev_err(&spi->dev,
> - "setup: %d Hz too slow, scbr %u; min %ld Hz\n",
> - xfer->speed_hz, scbr, bus_hz/255);
> - return -EINVAL;
> - }
> - if (scbr == 0) {
> - dev_err(&spi->dev,
> - "setup: %d Hz too high, scbr %u; max %ld Hz\n",
> - xfer->speed_hz, scbr, bus_hz);
> - return -EINVAL;
> - }
> - csr = spi_readl(as, CSR0 + 4 * spi->chip_select);
> - csr = SPI_BFINS(SCBR, scbr, csr);
> - spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
> -
> - return 0;
> -}
> -
> -/*
> - * Submit next transfer for PDC.
> - * lock is held, spi irq is blocked
> - */
> -static void atmel_spi_pdc_next_xfer(struct spi_master *master,
> - struct spi_message *msg,
> - struct spi_transfer *xfer)
> -{
> - struct atmel_spi *as = spi_master_get_devdata(master);
> - u32 len;
> - dma_addr_t tx_dma, rx_dma;
> -
> - spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
> -
> - len = as->current_remaining_bytes;
> - atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
> - as->current_remaining_bytes -= len;
> -
> - spi_writel(as, RPR, rx_dma);
> - spi_writel(as, TPR, tx_dma);
> -
> - if (msg->spi->bits_per_word > 8)
> - len >>= 1;
> - spi_writel(as, RCR, len);
> - spi_writel(as, TCR, len);
> -
> - dev_dbg(&msg->spi->dev,
> - " start xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
> - xfer, xfer->len, xfer->tx_buf,
> - (unsigned long long)xfer->tx_dma, xfer->rx_buf,
> - (unsigned long long)xfer->rx_dma);
> -
> - if (as->current_remaining_bytes) {
> - len = as->current_remaining_bytes;
> - atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
> - as->current_remaining_bytes -= len;
> -
> - spi_writel(as, RNPR, rx_dma);
> - spi_writel(as, TNPR, tx_dma);
> -
> - if (msg->spi->bits_per_word > 8)
> - len >>= 1;
> - spi_writel(as, RNCR, len);
> - spi_writel(as, TNCR, len);
> -
> - dev_dbg(&msg->spi->dev,
> - " next xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
> - xfer, xfer->len, xfer->tx_buf,
> - (unsigned long long)xfer->tx_dma, xfer->rx_buf,
> - (unsigned long long)xfer->rx_dma);
> - }
> -
> - /* REVISIT: We're waiting for RXBUFF before we start the next
> - * transfer because we need to handle some difficult timing
> - * issues otherwise. If we wait for TXBUFE in one transfer and
> - * then starts waiting for RXBUFF in the next, it's difficult
> - * to tell the difference between the RXBUFF interrupt we're
> - * actually waiting for and the RXBUFF interrupt of the
> - * previous transfer.
> - *
> - * It should be doable, though. Just not now...
> - */
> - spi_writel(as, IER, SPI_BIT(RXBUFF) | SPI_BIT(OVRES));
> - spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
> -}
> -
> -/*
> - * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
> - * - The buffer is either valid for CPU access, else NULL
> - * - If the buffer is valid, so is its DMA address
> - *
> - * This driver manages the dma address unless message->is_dma_mapped.
> - */
> -static int
> -atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
> -{
> - struct device *dev = &as->pdev->dev;
> -
> - xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
> - if (xfer->tx_buf) {
> - /* tx_buf is a const void* where we need a void * for the dma
> - * mapping */
> - void *nonconst_tx = (void *)xfer->tx_buf;
> -
> - xfer->tx_dma = dma_map_single(dev,
> - nonconst_tx, xfer->len,
> - DMA_TO_DEVICE);
> - if (dma_mapping_error(dev, xfer->tx_dma))
> - return -ENOMEM;
> - }
> - if (xfer->rx_buf) {
> - xfer->rx_dma = dma_map_single(dev,
> - xfer->rx_buf, xfer->len,
> - DMA_FROM_DEVICE);
> - if (dma_mapping_error(dev, xfer->rx_dma)) {
> - if (xfer->tx_buf)
> - dma_unmap_single(dev,
> - xfer->tx_dma, xfer->len,
> - DMA_TO_DEVICE);
> - return -ENOMEM;
> - }
> - }
> - return 0;
> -}
> -
> -static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
> - struct spi_transfer *xfer)
> -{
> - if (xfer->tx_dma != INVALID_DMA_ADDRESS)
> - dma_unmap_single(master->dev.parent, xfer->tx_dma,
> - xfer->len, DMA_TO_DEVICE);
> - if (xfer->rx_dma != INVALID_DMA_ADDRESS)
> - dma_unmap_single(master->dev.parent, xfer->rx_dma,
> - xfer->len, DMA_FROM_DEVICE);
> -}
> -
> -static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as)
> -{
> - spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
> -}
> -
> -static void
> -atmel_spi_pump_single_data(struct atmel_spi *as, struct spi_transfer *xfer)
> -{
> - u8 *rxp;
> - u16 *rxp16;
> - unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
> -
> - if (xfer->bits_per_word > 8) {
> - rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
> - *rxp16 = spi_readl(as, RDR);
> - } else {
> - rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
> - *rxp = spi_readl(as, RDR);
> - }
> - if (xfer->bits_per_word > 8) {
> - if (as->current_remaining_bytes > 2)
> - as->current_remaining_bytes -= 2;
> - else
> - as->current_remaining_bytes = 0;
> - } else {
> - as->current_remaining_bytes--;
> - }
> -}
> -
> -static void
> -atmel_spi_pump_fifo_data(struct atmel_spi *as, struct spi_transfer *xfer)
> -{
> - u32 fifolr = spi_readl(as, FLR);
> - u32 num_bytes, num_data = SPI_BFEXT(RXFL, fifolr);
> - u32 offset = xfer->len - as->current_remaining_bytes;
> - u16 *words = (u16 *)((u8 *)xfer->rx_buf + offset);
> - u8 *bytes = (u8 *)((u8 *)xfer->rx_buf + offset);
> - u16 rd; /* RD field is the lowest 16 bits of RDR */
> -
> - /* Update the number of remaining bytes to transfer */
> - num_bytes = ((xfer->bits_per_word > 8) ?
> - (num_data << 1) :
> - num_data);
> -
> - if (as->current_remaining_bytes > num_bytes)
> - as->current_remaining_bytes -= num_bytes;
> - else
> - as->current_remaining_bytes = 0;
> -
> - /* Handle odd number of bytes when data are more than 8bit width */
> - if (xfer->bits_per_word > 8)
> - as->current_remaining_bytes &= ~0x1;
> -
> - /* Read data */
> - while (num_data) {
> - rd = spi_readl(as, RDR);
> - if (xfer->bits_per_word > 8)
> - *words++ = rd;
> - else
> - *bytes++ = rd;
> - num_data--;
> - }
> -}
> -
> -/* Called from IRQ
> - *
> - * Must update "current_remaining_bytes" to keep track of data
> - * to transfer.
> - */
> -static void
> -atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
> -{
> - if (as->fifo_size)
> - atmel_spi_pump_fifo_data(as, xfer);
> - else
> - atmel_spi_pump_single_data(as, xfer);
> -}
> -
> -/* Interrupt
> - *
> - * No need for locking in this Interrupt handler: done_status is the
> - * only information modified.
> - */
> -static irqreturn_t
> -atmel_spi_pio_interrupt(int irq, void *dev_id)
> -{
> - struct spi_master *master = dev_id;
> - struct atmel_spi *as = spi_master_get_devdata(master);
> - u32 status, pending, imr;
> - struct spi_transfer *xfer;
> - int ret = IRQ_NONE;
> -
> - imr = spi_readl(as, IMR);
> - status = spi_readl(as, SR);
> - pending = status & imr;
> -
> - if (pending & SPI_BIT(OVRES)) {
> - ret = IRQ_HANDLED;
> - spi_writel(as, IDR, SPI_BIT(OVRES));
> - dev_warn(master->dev.parent, "overrun\n");
> -
> - /*
> - * When we get an overrun, we disregard the current
> - * transfer. Data will not be copied back from any
> - * bounce buffer and msg->actual_len will not be
> - * updated with the last xfer.
> - *
> - * We will also not process any remaning transfers in
> - * the message.
> - */
> - as->done_status = -EIO;
> - smp_wmb();
> -
> - /* Clear any overrun happening while cleaning up */
> - spi_readl(as, SR);
> -
> - complete(&as->xfer_completion);
> -
> - } else if (pending & (SPI_BIT(RDRF) | SPI_BIT(RXFTHF))) {
> - atmel_spi_lock(as);
> -
> - if (as->current_remaining_bytes) {
> - ret = IRQ_HANDLED;
> - xfer = as->current_transfer;
> - atmel_spi_pump_pio_data(as, xfer);
> - if (!as->current_remaining_bytes)
> - spi_writel(as, IDR, pending);
> -
> - complete(&as->xfer_completion);
> - }
> -
> - atmel_spi_unlock(as);
> - } else {
> - WARN_ONCE(pending, "IRQ not handled, pending = %x\n", pending);
> - ret = IRQ_HANDLED;
> - spi_writel(as, IDR, pending);
> - }
> -
> - return ret;
> -}
> -
> -static irqreturn_t
> -atmel_spi_pdc_interrupt(int irq, void *dev_id)
> -{
> - struct spi_master *master = dev_id;
> - struct atmel_spi *as = spi_master_get_devdata(master);
> - u32 status, pending, imr;
> - int ret = IRQ_NONE;
> -
> - imr = spi_readl(as, IMR);
> - status = spi_readl(as, SR);
> - pending = status & imr;
> -
> - if (pending & SPI_BIT(OVRES)) {
> -
> - ret = IRQ_HANDLED;
> -
> - spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
> - | SPI_BIT(OVRES)));
> -
> - /* Clear any overrun happening while cleaning up */
> - spi_readl(as, SR);
> -
> - as->done_status = -EIO;
> -
> - complete(&as->xfer_completion);
> -
> - } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
> - ret = IRQ_HANDLED;
> -
> - spi_writel(as, IDR, pending);
> -
> - complete(&as->xfer_completion);
> - }
> -
> - return ret;
> -}
> -
> -static int atmel_spi_setup(struct spi_device *spi)
> -{
> - struct atmel_spi *as;
> - struct atmel_spi_device *asd;
> - u32 csr;
> - unsigned int bits = spi->bits_per_word;
> - unsigned int npcs_pin;
> -
> - as = spi_master_get_devdata(spi->master);
> -
> - /* see notes above re chipselect */
> - if (!atmel_spi_is_v2(as)
> - && spi->chip_select == 0
> - && (spi->mode & SPI_CS_HIGH)) {
> - dev_dbg(&spi->dev, "setup: can't be active-high\n");
> - return -EINVAL;
> - }
> -
> - csr = SPI_BF(BITS, bits - 8);
> - if (spi->mode & SPI_CPOL)
> - csr |= SPI_BIT(CPOL);
> - if (!(spi->mode & SPI_CPHA))
> - csr |= SPI_BIT(NCPHA);
> - if (!as->use_cs_gpios)
> - csr |= SPI_BIT(CSAAT);
> -
> - /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
> - *
> - * DLYBCT would add delays between words, slowing down transfers.
> - * It could potentially be useful to cope with DMA bottlenecks, but
> - * in those cases it's probably best to just use a lower bitrate.
> - */
> - csr |= SPI_BF(DLYBS, 0);
> - csr |= SPI_BF(DLYBCT, 0);
> -
> - /* chipselect must have been muxed as GPIO (e.g. in board setup) */
> - npcs_pin = (unsigned long)spi->controller_data;
> -
> - if (!as->use_cs_gpios)
> - npcs_pin = spi->chip_select;
> - else if (gpio_is_valid(spi->cs_gpio))
> - npcs_pin = spi->cs_gpio;
> -
> - asd = spi->controller_state;
> - if (!asd) {
> - asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
> - if (!asd)
> - return -ENOMEM;
> -
> - if (as->use_cs_gpios)
> - gpio_direction_output(npcs_pin,
> - !(spi->mode & SPI_CS_HIGH));
> -
> - asd->npcs_pin = npcs_pin;
> - spi->controller_state = asd;
> - }
> -
> - asd->csr = csr;
> -
> - dev_dbg(&spi->dev,
> - "setup: bpw %u mode 0x%x -> csr%d %08x\n",
> - bits, spi->mode, spi->chip_select, csr);
> -
> - if (!atmel_spi_is_v2(as))
> - spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
> -
> - return 0;
> -}
> -
> -static int atmel_spi_one_transfer(struct spi_master *master,
> - struct spi_message *msg,
> - struct spi_transfer *xfer)
> -{
> - struct atmel_spi *as;
> - struct spi_device *spi = msg->spi;
> - u8 bits;
> - u32 len;
> - struct atmel_spi_device *asd;
> - int timeout;
> - int ret;
> - unsigned long dma_timeout;
> -
> - as = spi_master_get_devdata(master);
> -
> - if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
> - dev_dbg(&spi->dev, "missing rx or tx buf\n");
> - return -EINVAL;
> - }
> -
> - asd = spi->controller_state;
> - bits = (asd->csr >> 4) & 0xf;
> - if (bits != xfer->bits_per_word - 8) {
> - dev_dbg(&spi->dev,
> - "you can't yet change bits_per_word in transfers\n");
> - return -ENOPROTOOPT;
> - }
> -
> - /*
> - * DMA map early, for performance (empties dcache ASAP) and
> - * better fault reporting.
> - */
> - if ((!msg->is_dma_mapped)
> - && as->use_pdc) {
> - if (atmel_spi_dma_map_xfer(as, xfer) < 0)
> - return -ENOMEM;
> - }
> -
> - atmel_spi_set_xfer_speed(as, msg->spi, xfer);
> -
> - as->done_status = 0;
> - as->current_transfer = xfer;
> - as->current_remaining_bytes = xfer->len;
> - while (as->current_remaining_bytes) {
> - reinit_completion(&as->xfer_completion);
> -
> - if (as->use_pdc) {
> - atmel_spi_pdc_next_xfer(master, msg, xfer);
> - } else if (atmel_spi_use_dma(as, xfer)) {
> - len = as->current_remaining_bytes;
> - ret = atmel_spi_next_xfer_dma_submit(master,
> - xfer, &len);
> - if (ret) {
> - dev_err(&spi->dev,
> - "unable to use DMA, fallback to PIO\n");
> - atmel_spi_next_xfer_pio(master, xfer);
> - } else {
> - as->current_remaining_bytes -= len;
> - if (as->current_remaining_bytes < 0)
> - as->current_remaining_bytes = 0;
> - }
> - } else {
> - atmel_spi_next_xfer_pio(master, xfer);
> - }
> -
> - /* interrupts are disabled, so free the lock for schedule */
> - atmel_spi_unlock(as);
> - dma_timeout = wait_for_completion_timeout(&as->xfer_completion,
> - SPI_DMA_TIMEOUT);
> - atmel_spi_lock(as);
> - if (WARN_ON(dma_timeout == 0)) {
> - dev_err(&spi->dev, "spi transfer timeout\n");
> - as->done_status = -EIO;
> - }
> -
> - if (as->done_status)
> - break;
> - }
> -
> - if (as->done_status) {
> - if (as->use_pdc) {
> - dev_warn(master->dev.parent,
> - "overrun (%u/%u remaining)\n",
> - spi_readl(as, TCR), spi_readl(as, RCR));
> -
> - /*
> - * Clean up DMA registers and make sure the data
> - * registers are empty.
> - */
> - spi_writel(as, RNCR, 0);
> - spi_writel(as, TNCR, 0);
> - spi_writel(as, RCR, 0);
> - spi_writel(as, TCR, 0);
> - for (timeout = 1000; timeout; timeout--)
> - if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
> - break;
> - if (!timeout)
> - dev_warn(master->dev.parent,
> - "timeout waiting for TXEMPTY");
> - while (spi_readl(as, SR) & SPI_BIT(RDRF))
> - spi_readl(as, RDR);
> -
> - /* Clear any overrun happening while cleaning up */
> - spi_readl(as, SR);
> -
> - } else if (atmel_spi_use_dma(as, xfer)) {
> - atmel_spi_stop_dma(master);
> - }
> -
> - if (!msg->is_dma_mapped
> - && as->use_pdc)
> - atmel_spi_dma_unmap_xfer(master, xfer);
> -
> - return 0;
> -
> - } else {
> - /* only update length if no error */
> - msg->actual_length += xfer->len;
> - }
> -
> - if (!msg->is_dma_mapped
> - && as->use_pdc)
> - atmel_spi_dma_unmap_xfer(master, xfer);
> -
> - if (xfer->delay_usecs)
> - udelay(xfer->delay_usecs);
> -
> - if (xfer->cs_change) {
> - if (list_is_last(&xfer->transfer_list,
> - &msg->transfers)) {
> - as->keep_cs = true;
> - } else {
> - as->cs_active = !as->cs_active;
> - if (as->cs_active)
> - cs_activate(as, msg->spi);
> - else
> - cs_deactivate(as, msg->spi);
> - }
> - }
> -
> - return 0;
> -}
> -
> -static int atmel_spi_transfer_one_message(struct spi_master *master,
> - struct spi_message *msg)
> -{
> - struct atmel_spi *as;
> - struct spi_transfer *xfer;
> - struct spi_device *spi = msg->spi;
> - int ret = 0;
> -
> - as = spi_master_get_devdata(master);
> -
> - dev_dbg(&spi->dev, "new message %p submitted for %s\n",
> - msg, dev_name(&spi->dev));
> -
> - atmel_spi_lock(as);
> - cs_activate(as, spi);
> -
> - as->cs_active = true;
> - as->keep_cs = false;
> -
> - msg->status = 0;
> - msg->actual_length = 0;
> -
> - list_for_each_entry(xfer, &msg->transfers, transfer_list) {
> - ret = atmel_spi_one_transfer(master, msg, xfer);
> - if (ret)
> - goto msg_done;
> - }
> -
> - if (as->use_pdc)
> - atmel_spi_disable_pdc_transfer(as);
> -
> - list_for_each_entry(xfer, &msg->transfers, transfer_list) {
> - dev_dbg(&spi->dev,
> - " xfer %p: len %u tx %p/%pad rx %p/%pad\n",
> - xfer, xfer->len,
> - xfer->tx_buf, &xfer->tx_dma,
> - xfer->rx_buf, &xfer->rx_dma);
> - }
> -
> -msg_done:
> - if (!as->keep_cs)
> - cs_deactivate(as, msg->spi);
> -
> - atmel_spi_unlock(as);
> -
> - msg->status = as->done_status;
> - spi_finalize_current_message(spi->master);
> -
> - return ret;
> -}
> -
> -static void atmel_spi_cleanup(struct spi_device *spi)
> -{
> - struct atmel_spi_device *asd = spi->controller_state;
> -
> - if (!asd)
> - return;
> -
> - spi->controller_state = NULL;
> - kfree(asd);
> -}
> -
> -static inline unsigned int atmel_get_version(struct atmel_spi *as)
> -{
> - return spi_readl(as, VERSION) & 0x00000fff;
> -}
> -
> -static void atmel_get_caps(struct atmel_spi *as)
> -{
> - unsigned int version;
> -
> - version = atmel_get_version(as);
> -
> - as->caps.is_spi2 = version > 0x121;
> - as->caps.has_wdrbt = version >= 0x210;
> - as->caps.has_dma_support = version >= 0x212;
> - as->caps.has_pdc_support = version < 0x212;
> -}
> -
> -/*-------------------------------------------------------------------------*/
> -static int atmel_spi_gpio_cs(struct platform_device *pdev)
> -{
> - struct spi_master *master = platform_get_drvdata(pdev);
> - struct atmel_spi *as = spi_master_get_devdata(master);
> - struct device_node *np = master->dev.of_node;
> - int i;
> - int ret = 0;
> - int nb = 0;
> -
> - if (!as->use_cs_gpios)
> - return 0;
> -
> - if (!np)
> - return 0;
> -
> - nb = of_gpio_named_count(np, "cs-gpios");
> - for (i = 0; i < nb; i++) {
> - int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
> - "cs-gpios", i);
> -
> - if (cs_gpio == -EPROBE_DEFER)
> - return cs_gpio;
> -
> - if (gpio_is_valid(cs_gpio)) {
> - ret = devm_gpio_request(&pdev->dev, cs_gpio,
> - dev_name(&pdev->dev));
> - if (ret)
> - return ret;
> - }
> - }
> -
> - return 0;
> -}
> -
> -static void atmel_spi_init(struct atmel_spi *as)
> -{
> - spi_writel(as, CR, SPI_BIT(SWRST));
> - spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
> -
> - /* It is recommended to enable FIFOs first thing after reset */
> - if (as->fifo_size)
> - spi_writel(as, CR, SPI_BIT(FIFOEN));
> -
> - if (as->caps.has_wdrbt) {
> - spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
> - | SPI_BIT(MSTR));
> - } else {
> - spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
> - }
> -
> - if (as->use_pdc)
> - spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
> - spi_writel(as, CR, SPI_BIT(SPIEN));
> -}
> -
> -static int atmel_spi_probe(struct platform_device *pdev)
> -{
> - struct resource *regs;
> - int irq;
> - struct clk *clk;
> - int ret;
> - struct spi_master *master;
> - struct atmel_spi *as;
> -
> - /* Select default pin state */
> - pinctrl_pm_select_default_state(&pdev->dev);
> -
> - regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> - if (!regs)
> - return -ENXIO;
> -
> - irq = platform_get_irq(pdev, 0);
> - if (irq < 0)
> - return irq;
> -
> - clk = devm_clk_get(&pdev->dev, "spi_clk");
> - if (IS_ERR(clk))
> - return PTR_ERR(clk);
> -
> - /* setup spi core then atmel-specific driver state */
> - ret = -ENOMEM;
> - master = spi_alloc_master(&pdev->dev, sizeof(*as));
> - if (!master)
> - goto out_free;
> -
> - /* the spi->mode bits understood by this driver: */
> - master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
> - master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
> - master->dev.of_node = pdev->dev.of_node;
> - master->bus_num = pdev->id;
> - master->num_chipselect = master->dev.of_node ? 0 : 4;
> - master->setup = atmel_spi_setup;
> - master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX);
> - master->transfer_one_message = atmel_spi_transfer_one_message;
> - master->cleanup = atmel_spi_cleanup;
> - master->auto_runtime_pm = true;
> - master->max_dma_len = SPI_MAX_DMA_XFER;
> - master->can_dma = atmel_spi_can_dma;
> - platform_set_drvdata(pdev, master);
> -
> - as = spi_master_get_devdata(master);
> -
> - spin_lock_init(&as->lock);
> -
> - as->pdev = pdev;
> - as->regs = devm_ioremap_resource(&pdev->dev, regs);
> - if (IS_ERR(as->regs)) {
> - ret = PTR_ERR(as->regs);
> - goto out_unmap_regs;
> - }
> - as->phybase = regs->start;
> - as->irq = irq;
> - as->clk = clk;
> -
> - init_completion(&as->xfer_completion);
> -
> - atmel_get_caps(as);
> -
> - as->use_cs_gpios = true;
> - if (atmel_spi_is_v2(as) &&
> - pdev->dev.of_node &&
> - !of_get_property(pdev->dev.of_node, "cs-gpios", NULL)) {
> - as->use_cs_gpios = false;
> - master->num_chipselect = 4;
> - }
> -
> - ret = atmel_spi_gpio_cs(pdev);
> - if (ret)
> - goto out_unmap_regs;
> -
> - as->use_dma = false;
> - as->use_pdc = false;
> - if (as->caps.has_dma_support) {
> - ret = atmel_spi_configure_dma(master, as);
> - if (ret == 0) {
> - as->use_dma = true;
> - } else if (ret == -EPROBE_DEFER) {
> - return ret;
> - }
> - } else if (as->caps.has_pdc_support) {
> - as->use_pdc = true;
> - }
> -
> - if (IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
> - as->addr_rx_bbuf = dma_alloc_coherent(&pdev->dev,
> - SPI_MAX_DMA_XFER,
> - &as->dma_addr_rx_bbuf,
> - GFP_KERNEL | GFP_DMA);
> - if (!as->addr_rx_bbuf) {
> - as->use_dma = false;
> - } else {
> - as->addr_tx_bbuf = dma_alloc_coherent(&pdev->dev,
> - SPI_MAX_DMA_XFER,
> - &as->dma_addr_tx_bbuf,
> - GFP_KERNEL | GFP_DMA);
> - if (!as->addr_tx_bbuf) {
> - as->use_dma = false;
> - dma_free_coherent(&pdev->dev, SPI_MAX_DMA_XFER,
> - as->addr_rx_bbuf,
> - as->dma_addr_rx_bbuf);
> - }
> - }
> - if (!as->use_dma)
> - dev_info(master->dev.parent,
> - " can not allocate dma coherent memory\n");
> - }
> -
> - if (as->caps.has_dma_support && !as->use_dma)
> - dev_info(&pdev->dev, "Atmel SPI Controller using PIO only\n");
> -
> - if (as->use_pdc) {
> - ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pdc_interrupt,
> - 0, dev_name(&pdev->dev), master);
> - } else {
> - ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pio_interrupt,
> - 0, dev_name(&pdev->dev), master);
> - }
> - if (ret)
> - goto out_unmap_regs;
> -
> - /* Initialize the hardware */
> - ret = clk_prepare_enable(clk);
> - if (ret)
> - goto out_free_irq;
> -
> - as->spi_clk = clk_get_rate(clk);
> -
> - as->fifo_size = 0;
> - if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size",
> - &as->fifo_size)) {
> - dev_info(&pdev->dev, "Using FIFO (%u data)\n", as->fifo_size);
> - }
> -
> - atmel_spi_init(as);
> -
> - pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
> - pm_runtime_use_autosuspend(&pdev->dev);
> - pm_runtime_set_active(&pdev->dev);
> - pm_runtime_enable(&pdev->dev);
> -
> - ret = devm_spi_register_master(&pdev->dev, master);
> - if (ret)
> - goto out_free_dma;
> -
> - /* go! */
> - dev_info(&pdev->dev, "Atmel SPI Controller version 0x%x at 0x%08lx (irq %d)\n",
> - atmel_get_version(as), (unsigned long)regs->start,
> - irq);
> -
> - return 0;
> -
> -out_free_dma:
> - pm_runtime_disable(&pdev->dev);
> - pm_runtime_set_suspended(&pdev->dev);
> -
> - if (as->use_dma)
> - atmel_spi_release_dma(master);
> -
> - spi_writel(as, CR, SPI_BIT(SWRST));
> - spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
> - clk_disable_unprepare(clk);
> -out_free_irq:
> -out_unmap_regs:
> -out_free:
> - spi_master_put(master);
> - return ret;
> -}
> -
> -static int atmel_spi_remove(struct platform_device *pdev)
> -{
> - struct spi_master *master = platform_get_drvdata(pdev);
> - struct atmel_spi *as = spi_master_get_devdata(master);
> -
> - pm_runtime_get_sync(&pdev->dev);
> -
> - /* reset the hardware and block queue progress */
> - if (as->use_dma) {
> - atmel_spi_stop_dma(master);
> - atmel_spi_release_dma(master);
> - if (IS_ENABLED(CONFIG_SOC_SAM_V4_V5)) {
> - dma_free_coherent(&pdev->dev, SPI_MAX_DMA_XFER,
> - as->addr_tx_bbuf,
> - as->dma_addr_tx_bbuf);
> - dma_free_coherent(&pdev->dev, SPI_MAX_DMA_XFER,
> - as->addr_rx_bbuf,
> - as->dma_addr_rx_bbuf);
> - }
> - }
> -
> - spin_lock_irq(&as->lock);
> - spi_writel(as, CR, SPI_BIT(SWRST));
> - spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
> - spi_readl(as, SR);
> - spin_unlock_irq(&as->lock);
> -
> - clk_disable_unprepare(as->clk);
> -
> - pm_runtime_put_noidle(&pdev->dev);
> - pm_runtime_disable(&pdev->dev);
> -
> - return 0;
> -}
> -
> -#ifdef CONFIG_PM
> -static int atmel_spi_runtime_suspend(struct device *dev)
> -{
> - struct spi_master *master = dev_get_drvdata(dev);
> - struct atmel_spi *as = spi_master_get_devdata(master);
> -
> - clk_disable_unprepare(as->clk);
> - pinctrl_pm_select_sleep_state(dev);
> -
> - return 0;
> -}
> -
> -static int atmel_spi_runtime_resume(struct device *dev)
> -{
> - struct spi_master *master = dev_get_drvdata(dev);
> - struct atmel_spi *as = spi_master_get_devdata(master);
> -
> - pinctrl_pm_select_default_state(dev);
> -
> - return clk_prepare_enable(as->clk);
> -}
> -
> -#ifdef CONFIG_PM_SLEEP
> -static int atmel_spi_suspend(struct device *dev)
> -{
> - struct spi_master *master = dev_get_drvdata(dev);
> - int ret;
> -
> - /* Stop the queue running */
> - ret = spi_master_suspend(master);
> - if (ret) {
> - dev_warn(dev, "cannot suspend master\n");
> - return ret;
> - }
> -
> - if (!pm_runtime_suspended(dev))
> - atmel_spi_runtime_suspend(dev);
> -
> - return 0;
> -}
> -
> -static int atmel_spi_resume(struct device *dev)
> -{
> - struct spi_master *master = dev_get_drvdata(dev);
> - struct atmel_spi *as = spi_master_get_devdata(master);
> - int ret;
> -
> - ret = clk_prepare_enable(as->clk);
> - if (ret)
> - return ret;
> -
> - atmel_spi_init(as);
> -
> - clk_disable_unprepare(as->clk);
> -
> - if (!pm_runtime_suspended(dev)) {
> - ret = atmel_spi_runtime_resume(dev);
> - if (ret)
> - return ret;
> - }
> -
> - /* Start the queue running */
> - ret = spi_master_resume(master);
> - if (ret)
> - dev_err(dev, "problem starting queue (%d)\n", ret);
> -
> - return ret;
> -}
> -#endif
> -
> -static const struct dev_pm_ops atmel_spi_pm_ops = {
> - SET_SYSTEM_SLEEP_PM_OPS(atmel_spi_suspend, atmel_spi_resume)
> - SET_RUNTIME_PM_OPS(atmel_spi_runtime_suspend,
> - atmel_spi_runtime_resume, NULL)
> -};
> -#define ATMEL_SPI_PM_OPS (&atmel_spi_pm_ops)
> -#else
> -#define ATMEL_SPI_PM_OPS NULL
> -#endif
> -
> -#if defined(CONFIG_OF)
> -static const struct of_device_id atmel_spi_dt_ids[] = {
> - { .compatible = "atmel,at91rm9200-spi" },
> - { /* sentinel */ }
> -};
> -
> -MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids);
> -#endif
> -
> -static struct platform_driver atmel_spi_driver = {
> - .driver = {
> - .name = "atmel_spi",
> - .pm = ATMEL_SPI_PM_OPS,
> - .of_match_table = of_match_ptr(atmel_spi_dt_ids),
> - },
> - .probe = atmel_spi_probe,
> - .remove = atmel_spi_remove,
> -};
> -module_platform_driver(atmel_spi_driver);
> -
> -MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
> -MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
> -MODULE_LICENSE("GPL");
> -MODULE_ALIAS("platform:atmel_spi");
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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