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Message-ID: <1940888378.15639.1485811652002@email.1und1.de>
Date: Mon, 30 Jan 2017 22:27:31 +0100 (CET)
From: Stefan Wahren <stefan.wahren@...e.com>
To: Gerd Hoffmann <kraxel@...hat.com>
Cc: linux@...linux.org.uk, lee@...nel.org, rjui@...adcom.com,
eric@...olt.net, linux-rpi-kernel@...ts.infradead.org,
robh+dt@...nel.org, linux-arm-kernel@...ts.infradead.org,
ulf.hansson@...aro.org, sbranden@...adcom.com,
linux-kernel@...r.kernel.org, linux-mmc@...r.kernel.org,
bcm-kernel-feedback-list@...adcom.com, swarren@...dotorg.org,
mark.rutland@....com, f.fainelli@...il.com,
devicetree@...r.kernel.org
Subject: Re: [PATCH 2/4] mmc: bcm2835: Add new driver for the internal SD
controller.
Hi Gerd,
> Gerd Hoffmann <kraxel@...hat.com> hat am 27. Januar 2017 um 12:36 geschrieben:
>
>
> From: Eric Anholt <eric@...olt.net>
>
> The 2835 has two SD controllers: The Arasan SDHCI controller (supported
> by the iproc driver) and a custom SD controller. This patch adds a
> driver for the custom SD controller.
>
> The custom controller runs faster, and driving the sdcard with the
> custom controller also allows to drive the rpi3 wifi with the iproc
> driver.
>
> The code was originally written by Phil Elwell in the downstream
> Rasbperry Pi tree, and I did a major cleanup on it (+319, -707 lines
> out of the original 2055) for inclusion.
>
> Signed-off-by: Eric Anholt <eric@...olt.net>
>
> cleanups by Gerd Hoffmann:
>
> mmc: bcm2835: zap mmiowb()
> mmc: bcm2835: reset tweaks.
> mmc: bcm2835: more reset tweaks.
> mmc: bcm2835: rename bcm2835_sdhost to bcm2835
> mmc: bcm2835: whitespace & comment style
> mmc: bcm2835: zap bcm2835_write
> mmc: bcm2835: zap bcm2835_read
> mmc: bcm2835: zap bcm2835_read_relaxed
> mmc: bcm2835: zap bcm2835_set_ios fwd decl
> mmc: bcm2835: use dev_dbg()
> mmc: bcm2835: use dev_err()
> mmc: bcm2835: use dev_warn() + dev_into()
>
> cleanups by Stefan Wahren:
>
> mmc: bcm2835: Fix checkpatch.pl warning
> mmc: bcm2835: replace spaces with tabs
> mmc: bcm2835: remove bcm2835_set_power
> mmc: bcm2835: remove bcm2835_init()
> mmc: bcm2835: Avoid separate init statement
> mmc: bcm2835: Use local device ptr to make code more compact
> mmc: bcm2835: Use local ptr to make code more compact
> mmc: bcm2835: Use __func__ macro
> mmc: bcm2835: sort includes alphabetical
> mmc: bcm2835: fix includes
> mmc: bcm2835: refactor bcm2835_wait_transfer_complete()
> mmc: bcm2835: Handle error case of of_get_address
> mmc: bcm2835: Use MMC_SEND_OP_COND instead of number
> mmc: bcm2835: Rearrange mmc capabilities
>
> Signed-off-by: Stefan Wahren <stefan.wahren@...e.com>
>
> driver modernizations:
> * run most driver code in thread context.
> - use threaded irq handler.
> - schedule worker for timeout handling.
> * use mutex for locking, so we can easily sleep.
> * simplify poll/wait code, drop tasklet and work queue.
>
> Signed-off-by: Gerd Hoffmann <kraxel@...hat.com>
> ---
> drivers/mmc/host/Kconfig | 9 +
> drivers/mmc/host/Makefile | 1 +
> drivers/mmc/host/bcm2835.c | 1495 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 1505 insertions(+)
> create mode 100644 drivers/mmc/host/bcm2835.c
>
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 2eb9701..793adae 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -790,6 +790,15 @@ config MMC_TOSHIBA_PCI
> depends on PCI
> help
>
> +config MMC_BCM2835
> + tristate "platform support for the BCM2835 SDHOST MMC Controller"
> + depends on ARCH_BCM2835 || COMPILE_TEST
this will most likely cause build issues during COMPILE_TEST for platforms without DMA support. Greg's solution for the VCHIQ driver was to add the HAS_DMA dependency [1].
[1] - https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=f5f4c80e9a439cd3797ccfacb8393c4d7db3bdc4
> + help
> + This selects the BCM2835 SDHOST MMC controller. If you have a BCM2835
> + platform with SD or MMC devices, say Y or M here.
It would be good to provide at least a sentence why a user should choose this driver instead of IPROC.
> +
> + If unsure, say N.
> +
> config MMC_MTK
> tristate "MediaTek SD/MMC Card Interface support"
> depends on HAS_DMA
> diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
> index ccc9c4c..1a8fbab 100644
> --- a/drivers/mmc/host/Makefile
> +++ b/drivers/mmc/host/Makefile
> @@ -58,6 +58,7 @@ obj-$(CONFIG_MMC_MOXART) += moxart-mmc.o
> obj-$(CONFIG_MMC_SUNXI) += sunxi-mmc.o
> obj-$(CONFIG_MMC_USDHI6ROL0) += usdhi6rol0.o
> obj-$(CONFIG_MMC_TOSHIBA_PCI) += toshsd.o
> +obj-$(CONFIG_MMC_BCM2835) += bcm2835.o
>
> obj-$(CONFIG_MMC_REALTEK_PCI) += rtsx_pci_sdmmc.o
> obj-$(CONFIG_MMC_REALTEK_USB) += rtsx_usb_sdmmc.o
> diff --git a/drivers/mmc/host/bcm2835.c b/drivers/mmc/host/bcm2835.c
> new file mode 100644
> index 0000000..e8a3f6e
> --- /dev/null
> +++ b/drivers/mmc/host/bcm2835.c
> @@ -0,0 +1,1495 @@
> +/*
> + * BCM2835 SD host driver.
It would be nice to have a consistent notation for the driver name. There are too many in the driver, binding and config.
> + *
> + * Author: Phil Elwell <phil@...pberrypi.org>
> + * Copyright (C) 2015-2016 Raspberry Pi (Trading) Ltd.
> + *
> + * Based on
> + * mmc-bcm2835.c by Gellert Weisz
> + * which is, in turn, based on
> + * sdhci-bcm2708.c by Broadcom
> + * sdhci-bcm2835.c by Stephen Warren and Oleksandr Tymoshenko
> + * sdhci.c and sdhci-pci.c by Pierre Ossman
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/err.h>
> +#include <linux/highmem.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/platform_device.h>
> +#include <linux/scatterlist.h>
> +#include <linux/time.h>
> +#include <linux/workqueue.h>
> +
> +#include <linux/mmc/host.h>
> +#include <linux/mmc/mmc.h>
> +#include <linux/mmc/sd.h>
> +
> +#define SDCMD 0x00 /* Command to SD card - 16 R/W */
> +#define SDARG 0x04 /* Argument to SD card - 32 R/W */
> +#define SDTOUT 0x08 /* Start value for timeout counter - 32 R/W */
> +#define SDCDIV 0x0c /* Start value for clock divider - 11 R/W */
> +#define SDRSP0 0x10 /* SD card response (31:0) - 32 R */
> +#define SDRSP1 0x14 /* SD card response (63:32) - 32 R */
> +#define SDRSP2 0x18 /* SD card response (95:64) - 32 R */
> +#define SDRSP3 0x1c /* SD card response (127:96) - 32 R */
> +#define SDHSTS 0x20 /* SD host status - 11 R */
> +#define SDVDD 0x30 /* SD card power control - 1 R/W */
> +#define SDEDM 0x34 /* Emergency Debug Mode - 13 R/W */
> +#define SDHCFG 0x38 /* Host configuration - 2 R/W */
> +#define SDHBCT 0x3c /* Host byte count (debug) - 32 R/W */
> +#define SDDATA 0x40 /* Data to/from SD card - 32 R/W */
> +#define SDHBLC 0x50 /* Host block count (SDIO/SDHC) - 9 R/W */
> +
> +#define SDCMD_NEW_FLAG 0x8000
> +#define SDCMD_FAIL_FLAG 0x4000
> +#define SDCMD_BUSYWAIT 0x800
> +#define SDCMD_NO_RESPONSE 0x400
> +#define SDCMD_LONG_RESPONSE 0x200
> +#define SDCMD_WRITE_CMD 0x80
> +#define SDCMD_READ_CMD 0x40
> +#define SDCMD_CMD_MASK 0x3f
> +
> +#define SDCDIV_MAX_CDIV 0x7ff
> +
> +#define SDHSTS_BUSY_IRPT 0x400
> +#define SDHSTS_BLOCK_IRPT 0x200
> +#define SDHSTS_SDIO_IRPT 0x100
> +#define SDHSTS_REW_TIME_OUT 0x80
> +#define SDHSTS_CMD_TIME_OUT 0x40
> +#define SDHSTS_CRC16_ERROR 0x20
> +#define SDHSTS_CRC7_ERROR 0x10
> +#define SDHSTS_FIFO_ERROR 0x08
> +/* Reserved */
> +/* Reserved */
> +#define SDHSTS_DATA_FLAG 0x01
> +
> +#define SDHSTS_TRANSFER_ERROR_MASK (SDHSTS_CRC7_ERROR | \
> + SDHSTS_CRC16_ERROR | \
> + SDHSTS_REW_TIME_OUT | \
> + SDHSTS_FIFO_ERROR)
> +
> +#define SDHSTS_ERROR_MASK (SDHSTS_CMD_TIME_OUT | \
> + SDHSTS_TRANSFER_ERROR_MASK)
> +
> +#define SDHCFG_BUSY_IRPT_EN BIT(10)
> +#define SDHCFG_BLOCK_IRPT_EN BIT(8)
> +#define SDHCFG_SDIO_IRPT_EN BIT(5)
> +#define SDHCFG_DATA_IRPT_EN BIT(4)
> +#define SDHCFG_SLOW_CARD BIT(3)
> +#define SDHCFG_WIDE_EXT_BUS BIT(2)
> +#define SDHCFG_WIDE_INT_BUS BIT(1)
> +#define SDHCFG_REL_CMD_LINE BIT(0)
> +
> +#define SDVDD_POWER_OFF 0
> +#define SDVDD_POWER_ON 1
> +
> +#define SDEDM_FORCE_DATA_MODE BIT(19)
> +#define SDEDM_CLOCK_PULSE BIT(20)
> +#define SDEDM_BYPASS BIT(21)
> +
> +#define SDEDM_WRITE_THRESHOLD_SHIFT 9
> +#define SDEDM_READ_THRESHOLD_SHIFT 14
> +#define SDEDM_THRESHOLD_MASK 0x1f
> +
> +#define SDEDM_FSM_MASK 0xf
> +#define SDEDM_FSM_IDENTMODE 0x0
> +#define SDEDM_FSM_DATAMODE 0x1
> +#define SDEDM_FSM_READDATA 0x2
> +#define SDEDM_FSM_WRITEDATA 0x3
> +#define SDEDM_FSM_READWAIT 0x4
> +#define SDEDM_FSM_READCRC 0x5
> +#define SDEDM_FSM_WRITECRC 0x6
> +#define SDEDM_FSM_WRITEWAIT1 0x7
> +#define SDEDM_FSM_POWERDOWN 0x8
> +#define SDEDM_FSM_POWERUP 0x9
> +#define SDEDM_FSM_WRITESTART1 0xa
> +#define SDEDM_FSM_WRITESTART2 0xb
> +#define SDEDM_FSM_GENPULSES 0xc
> +#define SDEDM_FSM_WRITEWAIT2 0xd
> +#define SDEDM_FSM_STARTPOWDOWN 0xf
> +
> +#define SDDATA_FIFO_WORDS 16
> +
> +#define FIFO_READ_THRESHOLD 4
> +#define FIFO_WRITE_THRESHOLD 4
> +#define SDDATA_FIFO_PIO_BURST 8
> +#define CMD_DALLY_US 1
> +
> +struct bcm2835_host {
> + spinlock_t lock;
> + struct mutex mutex;
> +
> + void __iomem *ioaddr;
> + u32 phys_addr;
> +
> + struct mmc_host *mmc;
> + struct platform_device *pdev;
> +
> + u32 pio_timeout; /* In jiffies */
> + int clock; /* Current clock speed */
> + unsigned int max_clk; /* Max possible freq */
> + struct delayed_work timeout_work; /* Timer for timeouts */
> + struct sg_mapping_iter sg_miter; /* SG state for PIO */
> + unsigned int blocks; /* remaining PIO blocks */
> + int irq; /* Device IRQ */
> +
> + u32 ns_per_fifo_word;
> +
> + /* cached registers */
> + u32 hcfg;
> + u32 cdiv;
> +
> + struct mmc_request *mrq; /* Current request */
> + struct mmc_command *cmd; /* Current command */
> + struct mmc_data *data; /* Current data request */
> + bool data_complete:1;/* Data finished before cmd */
> + bool flush_fifo:1; /* Drain the fifo when finish */
> + bool use_busy:1; /* Wait for busy interrupt */
> + bool use_sbc:1; /* Send CMD23 */
> +
> + /* for threaded irq handler */
> + bool irq_block;
> + bool irq_busy;
> + bool irq_data;
> +
> + /* DMA part */
> + struct dma_chan *dma_chan_rx;
> + struct dma_chan *dma_chan_tx;
> + struct dma_chan *dma_chan;
> + struct dma_async_tx_descriptor *dma_desc;
> + u32 dma_dir;
> + u32 drain_words;
> + struct page *drain_page;
> + u32 drain_offset;
> + bool use_dma;
> +
> + int max_delay; /* maximum length of time spent waiting */
> + u32 pio_limit; /* Maximum block count for PIO (0 = DMA) */
> +};
> +
> +static void bcm2835_dumpcmd(struct bcm2835_host *host,
> + struct mmc_command *cmd,
> + const char *label)
> +{
> + struct device *dev = &host->pdev->dev;
> +
> + if (!cmd)
> + return;
> +
> + dev_dbg(dev, "%c%s op %d arg 0x%x flags 0x%x - resp %08x %08x %08x %08x, err %d\n",
> + (cmd == host->cmd) ? '>' : ' ',
> + label, cmd->opcode, cmd->arg, cmd->flags,
> + cmd->resp[0], cmd->resp[1], cmd->resp[2], cmd->resp[3],
> + cmd->error);
> +}
> +
> +static void bcm2835_dumpregs(struct bcm2835_host *host)
> +{
> + struct mmc_request *mrq = host->mrq;
> + struct device *dev = &host->pdev->dev;
> +
> + if (mrq) {
> + bcm2835_dumpcmd(host, mrq->sbc, "sbc");
> + bcm2835_dumpcmd(host, mrq->cmd, "cmd");
> + if (mrq->data) {
> + dev_dbg(dev, "data blocks %x blksz %x - err %d\n",
> + mrq->data->blocks,
> + mrq->data->blksz,
> + mrq->data->error);
> + }
> + bcm2835_dumpcmd(host, mrq->stop, "stop");
> + }
> +
> + dev_dbg(dev, "=========== REGISTER DUMP ===========\n");
> + dev_dbg(dev, "SDCMD 0x%08x\n", readl(host->ioaddr + SDCMD));
> + dev_dbg(dev, "SDARG 0x%08x\n", readl(host->ioaddr + SDARG));
> + dev_dbg(dev, "SDTOUT 0x%08x\n", readl(host->ioaddr + SDTOUT));
> + dev_dbg(dev, "SDCDIV 0x%08x\n", readl(host->ioaddr + SDCDIV));
> + dev_dbg(dev, "SDRSP0 0x%08x\n", readl(host->ioaddr + SDRSP0));
> + dev_dbg(dev, "SDRSP1 0x%08x\n", readl(host->ioaddr + SDRSP1));
> + dev_dbg(dev, "SDRSP2 0x%08x\n", readl(host->ioaddr + SDRSP2));
> + dev_dbg(dev, "SDRSP3 0x%08x\n", readl(host->ioaddr + SDRSP3));
> + dev_dbg(dev, "SDHSTS 0x%08x\n", readl(host->ioaddr + SDHSTS));
> + dev_dbg(dev, "SDVDD 0x%08x\n", readl(host->ioaddr + SDVDD));
> + dev_dbg(dev, "SDEDM 0x%08x\n", readl(host->ioaddr + SDEDM));
> + dev_dbg(dev, "SDHCFG 0x%08x\n", readl(host->ioaddr + SDHCFG));
> + dev_dbg(dev, "SDHBCT 0x%08x\n", readl(host->ioaddr + SDHBCT));
> + dev_dbg(dev, "SDHBLC 0x%08x\n", readl(host->ioaddr + SDHBLC));
> + dev_dbg(dev, "===========================================\n");
> +}
> +
> +static void bcm2835_reset_internal(struct bcm2835_host *host)
> +{
> + u32 temp;
> +
> + writel(SDVDD_POWER_OFF, host->ioaddr + SDVDD);
> + writel(0, host->ioaddr + SDCMD);
> + writel(0, host->ioaddr + SDARG);
> + writel(0xf00000, host->ioaddr + SDTOUT);
> + writel(0, host->ioaddr + SDCDIV);
> + writel(0x7f8, host->ioaddr + SDHSTS); /* Write 1s to clear */
> + writel(0, host->ioaddr + SDHCFG);
> + writel(0, host->ioaddr + SDHBCT);
> + writel(0, host->ioaddr + SDHBLC);
> +
> + /* Limit fifo usage due to silicon bug */
> + temp = readl(host->ioaddr + SDEDM);
> + temp &= ~((SDEDM_THRESHOLD_MASK << SDEDM_READ_THRESHOLD_SHIFT) |
> + (SDEDM_THRESHOLD_MASK << SDEDM_WRITE_THRESHOLD_SHIFT));
> + temp |= (FIFO_READ_THRESHOLD << SDEDM_READ_THRESHOLD_SHIFT) |
> + (FIFO_WRITE_THRESHOLD << SDEDM_WRITE_THRESHOLD_SHIFT);
> + writel(temp, host->ioaddr + SDEDM);
> + msleep(20);
> + writel(SDVDD_POWER_ON, host->ioaddr + SDVDD);
> + msleep(20);
> + host->clock = 0;
> + writel(host->hcfg, host->ioaddr + SDHCFG);
> + writel(host->cdiv, host->ioaddr + SDCDIV);
> +}
> +
> +static void bcm2835_reset(struct mmc_host *mmc)
> +{
> + struct bcm2835_host *host = mmc_priv(mmc);
> +
> + if (host->dma_chan)
> + dmaengine_terminate_sync(host->dma_chan);
> + bcm2835_reset_internal(host);
> +}
> +
> +static void bcm2835_finish_data(struct bcm2835_host *host);
> +static void bcm2835_finish_command(struct bcm2835_host *host);
> +static void bcm2835_finish_request(struct bcm2835_host *host);
> +
> +static void bcm2835_wait_transfer_complete(struct bcm2835_host *host)
> +{
> + int timediff;
> + u32 alternate_idle;
> +
> + alternate_idle = (host->mrq->data->flags & MMC_DATA_READ) ?
> + SDEDM_FSM_READWAIT : SDEDM_FSM_WRITESTART1;
> +
> + timediff = 0;
> +
> + while (1) {
> + u32 edm, fsm;
> +
> + edm = readl(host->ioaddr + SDEDM);
> + fsm = edm & SDEDM_FSM_MASK;
> +
> + if ((fsm == SDEDM_FSM_IDENTMODE) ||
> + (fsm == SDEDM_FSM_DATAMODE))
> + break;
> + if (fsm == alternate_idle) {
> + writel(edm | SDEDM_FORCE_DATA_MODE,
> + host->ioaddr + SDEDM);
> + break;
> + }
> +
> + timediff++;
> + if (timediff == 100000) {
> + dev_err(&host->pdev->dev,
> + "wait_transfer_complete - still waiting after %d retries\n",
> + timediff);
> + bcm2835_dumpregs(host);
> + host->mrq->data->error = -ETIMEDOUT;
> + return;
> + }
> + cpu_relax();
> + }
> +}
> +
> +static void bcm2835_dma_complete(void *param)
> +{
> + struct bcm2835_host *host = param;
> + struct mmc_data *data = host->data;
> +
> + mutex_lock(&host->mutex);
> +
> + if (host->dma_chan) {
> + dma_unmap_sg(host->dma_chan->device->dev,
> + data->sg, data->sg_len,
> + host->dma_dir);
> +
> + host->dma_chan = NULL;
> + }
> +
> + if (host->drain_words) {
> + void *page;
> + u32 *buf;
> +
> + page = kmap_atomic(host->drain_page);
> + buf = page + host->drain_offset;
> +
> + while (host->drain_words) {
> + u32 edm = readl(host->ioaddr + SDEDM);
> +
> + if ((edm >> 4) & 0x1f)
> + *(buf++) = readl(host->ioaddr + SDDATA);
> + host->drain_words--;
> + }
> +
> + kunmap_atomic(page);
> + }
> +
> + bcm2835_finish_data(host);
> +
> + mutex_unlock(&host->mutex);
> +}
> +
> +static void bcm2835_transfer_block_pio(struct bcm2835_host *host,
> + bool is_read)
> +{
> + unsigned long flags;
> + size_t blksize, len;
> + u32 *buf;
> + unsigned long wait_max;
> +
> + blksize = host->data->blksz;
> +
> + wait_max = jiffies + msecs_to_jiffies(host->pio_timeout);
> +
> + local_irq_save(flags);
> +
> + while (blksize) {
> + int copy_words;
> + u32 hsts = 0;
> +
> + if (!sg_miter_next(&host->sg_miter)) {
> + host->data->error = -EINVAL;
> + break;
> + }
> +
> + len = min(host->sg_miter.length, blksize);
> + if (len % 4) {
> + host->data->error = -EINVAL;
> + break;
> + }
> +
> + blksize -= len;
> + host->sg_miter.consumed = len;
> +
> + buf = (u32 *)host->sg_miter.addr;
> +
> + copy_words = len / 4;
> +
> + while (copy_words) {
> + int burst_words, words;
> + u32 edm;
> +
> + burst_words = SDDATA_FIFO_PIO_BURST;
> + if (burst_words > copy_words)
> + burst_words = copy_words;
> + edm = readl(host->ioaddr + SDEDM);
> + if (is_read)
> + words = ((edm >> 4) & 0x1f);
> + else
> + words = SDDATA_FIFO_WORDS - ((edm >> 4) & 0x1f);
> +
> + if (words < burst_words) {
> + int fsm_state = (edm & SDEDM_FSM_MASK);
> + struct device *dev = &host->pdev->dev;
> +
> + if ((is_read &&
> + (fsm_state != SDEDM_FSM_READDATA &&
> + fsm_state != SDEDM_FSM_READWAIT &&
> + fsm_state != SDEDM_FSM_READCRC)) ||
> + (!is_read &&
> + (fsm_state != SDEDM_FSM_WRITEDATA &&
> + fsm_state != SDEDM_FSM_WRITESTART1 &&
> + fsm_state != SDEDM_FSM_WRITESTART2))) {
> + hsts = readl(host->ioaddr + SDHSTS);
> + dev_err(dev, "fsm %x, hsts %x\n",
> + fsm_state, hsts);
> + if (hsts & SDHSTS_ERROR_MASK)
> + break;
> + }
> +
> + if (time_after(jiffies, wait_max)) {
> + dev_err(dev, "PIO %s timeout - EDM %x\n",
> + is_read ? "read" : "write",
> + edm);
> + hsts = SDHSTS_REW_TIME_OUT;
> + break;
> + }
> + ndelay((burst_words - words) *
> + host->ns_per_fifo_word);
> + continue;
> + } else if (words > copy_words) {
> + words = copy_words;
> + }
> +
> + copy_words -= words;
> +
> + while (words) {
> + if (is_read)
> + *(buf++) = readl(host->ioaddr + SDDATA);
> + else
> + writel(*(buf++), host->ioaddr + SDDATA);
> + words--;
> + }
> + }
> +
> + if (hsts & SDHSTS_ERROR_MASK)
> + break;
> + }
> +
> + sg_miter_stop(&host->sg_miter);
> +
> + local_irq_restore(flags);
> +}
> +
> +static void bcm2835_transfer_pio(struct bcm2835_host *host)
> +{
> + struct device *dev = &host->pdev->dev;
> + u32 sdhsts;
> + bool is_read;
> +
> + is_read = (host->data->flags & MMC_DATA_READ) != 0;
> + bcm2835_transfer_block_pio(host, is_read);
> +
> + sdhsts = readl(host->ioaddr + SDHSTS);
> + if (sdhsts & (SDHSTS_CRC16_ERROR |
> + SDHSTS_CRC7_ERROR |
> + SDHSTS_FIFO_ERROR)) {
> + dev_err(dev, "%s transfer error - HSTS %x\n",
> + is_read ? "read" : "write",
> + sdhsts);
> + host->data->error = -EILSEQ;
> + } else if ((sdhsts & (SDHSTS_CMD_TIME_OUT |
> + SDHSTS_REW_TIME_OUT))) {
> + dev_err(dev, "%s timeout error - HSTS %x\n",
> + is_read ? "read" : "write",
> + sdhsts);
> + host->data->error = -ETIMEDOUT;
> + }
> +}
> +
> +static void bcm2835_prepare_dma(struct bcm2835_host *host,
> + struct mmc_data *data)
> +{
> + int len, dir_data, dir_slave;
> + struct dma_async_tx_descriptor *desc = NULL;
> + struct dma_chan *dma_chan;
> +
> + dev_dbg(&host->pdev->dev, "bcm2835_prepare_dma()\n");
> +
> + if (data->flags & MMC_DATA_READ) {
> + dma_chan = host->dma_chan_rx;
> + dir_data = DMA_FROM_DEVICE;
> + dir_slave = DMA_DEV_TO_MEM;
> + } else {
> + dma_chan = host->dma_chan_tx;
> + dir_data = DMA_TO_DEVICE;
> + dir_slave = DMA_MEM_TO_DEV;
> + }
> +
> + /* The block doesn't manage the FIFO DREQs properly for
> + * multi-block transfers, so don't attempt to DMA the final
> + * few words. Unfortunately this requires the final sg entry
> + * to be trimmed. N.B. This code demands that the overspill
> + * is contained in a single sg entry.
> + */
> +
> + host->drain_words = 0;
> + if ((data->blocks > 1) && (dir_data == DMA_FROM_DEVICE)) {
> + struct scatterlist *sg;
> + u32 len;
> + int i;
> +
> + len = min((u32)(FIFO_READ_THRESHOLD - 1) * 4,
> + (u32)data->blocks * data->blksz);
> +
> + for_each_sg(data->sg, sg, data->sg_len, i) {
> + if (sg_is_last(sg)) {
> + WARN_ON(sg->length < len);
> + sg->length -= len;
> + host->drain_page = (struct page *)sg->page_link;
> + host->drain_offset = sg->offset + sg->length;
> + }
> + }
> + host->drain_words = len / 4;
> + }
> +
> + len = dma_map_sg(dma_chan->device->dev, data->sg, data->sg_len,
> + dir_data);
> +
> + if (len > 0) {
> + desc = dmaengine_prep_slave_sg(dma_chan, data->sg,
> + len, dir_slave,
> + DMA_PREP_INTERRUPT |
> + DMA_CTRL_ACK);
> + }
> +
> + if (desc) {
> + desc->callback = bcm2835_dma_complete;
> + desc->callback_param = host;
> + host->dma_desc = desc;
> + host->dma_chan = dma_chan;
> + host->dma_dir = dir_data;
> + }
> +}
> +
> +static void bcm2835_start_dma(struct bcm2835_host *host)
> +{
> + dmaengine_submit(host->dma_desc);
> + dma_async_issue_pending(host->dma_chan);
> +}
> +
> +static void bcm2835_set_transfer_irqs(struct bcm2835_host *host)
> +{
> + u32 all_irqs = SDHCFG_DATA_IRPT_EN | SDHCFG_BLOCK_IRPT_EN |
> + SDHCFG_BUSY_IRPT_EN;
> +
> + if (host->dma_desc) {
> + host->hcfg = (host->hcfg & ~all_irqs) |
> + SDHCFG_BUSY_IRPT_EN;
> + } else {
> + host->hcfg = (host->hcfg & ~all_irqs) |
> + SDHCFG_DATA_IRPT_EN |
> + SDHCFG_BUSY_IRPT_EN;
> + }
> +
> + writel(host->hcfg, host->ioaddr + SDHCFG);
> +}
> +
> +static void bcm2835_prepare_data(struct bcm2835_host *host,
> + struct mmc_command *cmd)
> +{
> + struct mmc_data *data = cmd->data;
> +
> + WARN_ON(host->data);
> +
> + host->data = data;
> + if (!data)
> + return;
> +
> + /* Sanity checks */
> + WARN_ON(data->blksz * data->blocks > 524288);
> + WARN_ON(data->blksz > host->mmc->max_blk_size);
> + WARN_ON(data->blocks > 65535);
I think these 3 warnings should be dropped. Maybe this is already checked by the mmc core.
> +
> + host->data_complete = false;
> + host->flush_fifo = false;
> + host->data->bytes_xfered = 0;
> +
> + if (!host->dma_desc) {
> + /* Use PIO */
> + int flags = SG_MITER_ATOMIC;
> +
> + if (data->flags & MMC_DATA_READ)
> + flags |= SG_MITER_TO_SG;
> + else
> + flags |= SG_MITER_FROM_SG;
> + sg_miter_start(&host->sg_miter, data->sg, data->sg_len, flags);
> + host->blocks = data->blocks;
> + }
> +
> + bcm2835_set_transfer_irqs(host);
> +
> + writel(data->blksz, host->ioaddr + SDHBCT);
> + writel(data->blocks, host->ioaddr + SDHBLC);
> +}
> +
> +static u32 bcm2835_read_wait_sdcmd(struct bcm2835_host *host, u32 max_ms,
> + bool check_fail)
> +{
> + struct device *dev = &host->pdev->dev;
> + u32 value;
> + int ret;
> +
> + ret = readl_poll_timeout(host->ioaddr + SDCMD, value,
> + (!(value & SDCMD_NEW_FLAG)) ||
> + (check_fail && (value & SDCMD_FAIL_FLAG)),
> + 1, 10);
> + if (ret == -ETIMEDOUT)
> + /* if it takes a while make poll interval bigger */
> + ret = readl_poll_timeout(host->ioaddr + SDCMD, value,
> + (!(value & SDCMD_NEW_FLAG)) ||
> + (check_fail && (value & SDCMD_FAIL_FLAG)),
> + 10, max_ms * 1000);
> + if (ret == -ETIMEDOUT)
> + dev_err(dev, "%s: timeout (%d ms)\n",
> + __func__, max_ms);
> +
> + return value;
> +}
> +
> +bool bcm2835_send_command(struct bcm2835_host *host,
> + struct mmc_command *cmd)
> +{
> + struct device *dev = &host->pdev->dev;
> + u32 sdcmd, sdhsts;
> + unsigned long timeout;
> +
> + WARN_ON(host->cmd);
> +
> + if (cmd->data) {
> + dev_dbg(dev, "send_command %d 0x%x (flags 0x%x) - %s %d*%d\n",
> + cmd->opcode, cmd->arg, cmd->flags,
> + (cmd->data->flags & MMC_DATA_READ) ?
> + "read" : "write", cmd->data->blocks,
> + cmd->data->blksz);
> + } else {
> + dev_dbg(dev, "send_command %d 0x%x (flags 0x%x)\n",
> + cmd->opcode, cmd->arg, cmd->flags);
> + }
> +
> + sdcmd = bcm2835_read_wait_sdcmd(host, 100, false);
> + if (sdcmd & SDCMD_NEW_FLAG) {
> + dev_err(dev, "previous command never completed.\n");
> + bcm2835_dumpregs(host);
> + cmd->error = -EILSEQ;
> + bcm2835_finish_request(host);
> + return false;
> + }
> +
> + if (!cmd->data && cmd->busy_timeout > 9000)
> + timeout = DIV_ROUND_UP(cmd->busy_timeout, 1000) * HZ + HZ;
> + else
> + timeout = 10 * HZ;
> + schedule_delayed_work(&host->timeout_work, timeout);
> +
> + host->cmd = cmd;
> +
> + /* Clear any error flags */
> + sdhsts = readl(host->ioaddr + SDHSTS);
> + if (sdhsts & SDHSTS_ERROR_MASK)
> + writel(sdhsts, host->ioaddr + SDHSTS);
> +
> + if ((cmd->flags & MMC_RSP_136) && (cmd->flags & MMC_RSP_BUSY)) {
> + dev_err(dev, "unsupported response type!\n");
> + cmd->error = -EINVAL;
> + bcm2835_finish_request(host);
> + return false;
> + }
> +
> + bcm2835_prepare_data(host, cmd);
> +
> + writel(cmd->arg, host->ioaddr + SDARG);
> +
> + sdcmd = cmd->opcode & SDCMD_CMD_MASK;
> +
> + host->use_busy = false;
> + if (!(cmd->flags & MMC_RSP_PRESENT)) {
> + sdcmd |= SDCMD_NO_RESPONSE;
> + } else {
> + if (cmd->flags & MMC_RSP_136)
> + sdcmd |= SDCMD_LONG_RESPONSE;
> + if (cmd->flags & MMC_RSP_BUSY) {
> + sdcmd |= SDCMD_BUSYWAIT;
> + host->use_busy = true;
> + }
> + }
> +
> + if (cmd->data) {
> + if (cmd->data->flags & MMC_DATA_WRITE)
> + sdcmd |= SDCMD_WRITE_CMD;
> + if (cmd->data->flags & MMC_DATA_READ)
> + sdcmd |= SDCMD_READ_CMD;
> + }
> +
> + writel(sdcmd | SDCMD_NEW_FLAG, host->ioaddr + SDCMD);
> +
> + return true;
> +}
> +
> +static void bcm2835_transfer_complete(struct bcm2835_host *host)
> +{
> + struct mmc_data *data;
> +
> + WARN_ON(!host->data_complete);
> +
> + data = host->data;
> + host->data = NULL;
> +
> + dev_dbg(&host->pdev->dev, "transfer_complete(error %d, stop %d)\n",
> + data->error, data->stop ? 1 : 0);
> +
> + /* Need to send CMD12 if -
> + * a) open-ended multiblock transfer (no CMD23)
> + * b) error in multiblock transfer
> + */
> + if (host->mrq->stop && (data->error || !host->use_sbc)) {
> + if (bcm2835_send_command(host, host->mrq->stop)) {
> + /* No busy, so poll for completion */
> + if (!host->use_busy)
> + bcm2835_finish_command(host);
> + }
> + } else {
> + bcm2835_wait_transfer_complete(host);
> + bcm2835_finish_request(host);
> + }
> +}
> +
> +static void bcm2835_finish_data(struct bcm2835_host *host)
> +{
> + struct device *dev = &host->pdev->dev;
> + struct mmc_data *data;
> +
> + data = host->data;
> +
> + dev_dbg(dev, "finish_data(error %d, stop %d, sbc %d)\n",
> + data->error, data->stop ? 1 : 0,
> + host->mrq->sbc ? 1 : 0);
> +
> + host->hcfg &= ~(SDHCFG_DATA_IRPT_EN | SDHCFG_BLOCK_IRPT_EN);
> + writel(host->hcfg, host->ioaddr + SDHCFG);
> +
> + data->bytes_xfered = data->error ? 0 : (data->blksz * data->blocks);
> +
> + host->data_complete = true;
> +
> + if (host->cmd) {
> + /* Data managed to finish before the
> + * command completed. Make sure we do
> + * things in the proper order.
> + */
> + dev_dbg(dev, "Finished early - HSTS %x\n",
> + readl(host->ioaddr + SDHSTS));
> + } else {
> + bcm2835_transfer_complete(host);
> + }
> +}
> +
> +static void bcm2835_finish_command(struct bcm2835_host *host)
> +{
> + struct device *dev = &host->pdev->dev;
> + struct mmc_command *cmd = host->cmd;
> + u32 sdcmd;
> +
> + dev_dbg(dev, "finish_command(%x)\n", readl(host->ioaddr + SDCMD));
> +
> + sdcmd = bcm2835_read_wait_sdcmd(host, 100, true);
> +
> + /* Check for errors */
> + if (sdcmd & SDCMD_NEW_FLAG) {
> + dev_err(dev, "command never completed.\n");
> + bcm2835_dumpregs(host);
> + host->cmd->error = -EIO;
> + bcm2835_finish_request(host);
> + return;
> + } else if (sdcmd & SDCMD_FAIL_FLAG) {
> + u32 sdhsts = readl(host->ioaddr + SDHSTS);
> +
> + /* Clear the errors */
> + writel(SDHSTS_ERROR_MASK, host->ioaddr + SDHSTS);
> +
> + if (!(sdhsts & SDHSTS_CRC7_ERROR) ||
> + (host->cmd->opcode != MMC_SEND_OP_COND)) {
> + if (sdhsts & SDHSTS_CMD_TIME_OUT) {
> + host->cmd->error = -ETIMEDOUT;
> + } else {
> + dev_err(dev, "unexpected command %d error\n",
> + host->cmd->opcode);
> + bcm2835_dumpregs(host);
> + host->cmd->error = -EILSEQ;
> + }
> + bcm2835_finish_request(host);
> + return;
> + }
> + }
> +
> + if (cmd->flags & MMC_RSP_PRESENT) {
> + if (cmd->flags & MMC_RSP_136) {
> + int i;
> +
> + for (i = 0; i < 4; i++) {
> + cmd->resp[3 - i] =
> + readl(host->ioaddr + SDRSP0 + i * 4);
> + }
> +
> + dev_dbg(dev, "finish_command %08x %08x %08x %08x\n",
> + cmd->resp[0], cmd->resp[1],
> + cmd->resp[2], cmd->resp[3]);
> + } else {
> + cmd->resp[0] = readl(host->ioaddr + SDRSP0);
> + dev_dbg(dev, "finish_command %08x\n", cmd->resp[0]);
> + }
> + }
> +
> + if (cmd == host->mrq->sbc) {
> + /* Finished CMD23, now send actual command. */
> + host->cmd = NULL;
> + if (bcm2835_send_command(host, host->mrq->cmd)) {
> + if (host->data && host->dma_desc)
> + /* DMA transfer starts now, PIO starts
> + * after irq
> + */
> + bcm2835_start_dma(host);
> +
> + if (!host->use_busy)
> + bcm2835_finish_command(host);
> + }
> + } else if (cmd == host->mrq->stop) {
> + /* Finished CMD12 */
> + bcm2835_finish_request(host);
> + } else {
> + /* Processed actual command. */
> + host->cmd = NULL;
> + if (!host->data)
> + bcm2835_finish_request(host);
> + else if (host->data_complete)
> + bcm2835_transfer_complete(host);
> + }
> +}
> +
> +static void bcm2835_timeout(struct work_struct *work)
> +{
> + struct delayed_work *d = to_delayed_work(work);
> + struct bcm2835_host *host =
> + container_of(d, struct bcm2835_host, timeout_work);
> + struct device *dev = &host->pdev->dev;
> +
> + mutex_lock(&host->mutex);
> +
> + if (host->mrq) {
> + dev_err(dev, "timeout waiting for hardware interrupt.\n");
> + bcm2835_dumpregs(host);
> +
> + if (host->data) {
> + host->data->error = -ETIMEDOUT;
> + bcm2835_finish_data(host);
> + } else {
> + if (host->cmd)
> + host->cmd->error = -ETIMEDOUT;
> + else
> + host->mrq->cmd->error = -ETIMEDOUT;
> +
> + dev_dbg(dev, "timeout_timer tasklet_schedule\n");
> + bcm2835_finish_request(host);
> + }
> + }
> +
> + mutex_unlock(&host->mutex);
> +}
> +
> +static bool bcm2835_check_cmd_error(struct bcm2835_host *host, u32 intmask)
> +{
> + struct device *dev = &host->pdev->dev;
> +
> + if (!(intmask & SDHSTS_ERROR_MASK))
> + return false;
> +
> + if (!host->cmd)
> + return true;
> +
> + dev_err(dev, "sdhost_busy_irq: intmask %x, data %p\n",
> + intmask, host->mrq->data);
> + if (intmask & SDHSTS_CRC7_ERROR) {
> + host->cmd->error = -EILSEQ;
> + } else if (intmask & (SDHSTS_CRC16_ERROR |
> + SDHSTS_FIFO_ERROR)) {
> + if (host->mrq->data)
> + host->mrq->data->error = -EILSEQ;
> + else
> + host->cmd->error = -EILSEQ;
> + } else if (intmask & SDHSTS_REW_TIME_OUT) {
> + if (host->mrq->data)
> + host->mrq->data->error = -ETIMEDOUT;
> + else
> + host->cmd->error = -ETIMEDOUT;
> + } else if (intmask & SDHSTS_CMD_TIME_OUT) {
> + host->cmd->error = -ETIMEDOUT;
> + }
> + bcm2835_dumpregs(host);
> + return true;
> +}
> +
> +static void bcm2835_check_data_error(struct bcm2835_host *host, u32 intmask)
> +{
> + if (!host->data)
> + return;
> + if (intmask & (SDHSTS_CRC16_ERROR | SDHSTS_FIFO_ERROR))
> + host->data->error = -EILSEQ;
> + if (intmask & SDHSTS_REW_TIME_OUT)
> + host->data->error = -ETIMEDOUT;
> +}
> +
> +static void bcm2835_busy_irq(struct bcm2835_host *host)
> +{
> + if (WARN_ON(!host->cmd)) {
> + bcm2835_dumpregs(host);
> + return;
> + }
> +
> + if (WARN_ON(!host->use_busy)) {
> + bcm2835_dumpregs(host);
> + return;
> + }
> + host->use_busy = false;
> +
> + bcm2835_finish_command(host);
> +}
> +
> +static void bcm2835_data_irq(struct bcm2835_host *host, u32 intmask)
> +{
> + /* There are no dedicated data/space available interrupt
> + * status bits, so it is necessary to use the single shared
> + * data/space available FIFO status bits. It is therefore not
> + * an error to get here when there is no data transfer in
> + * progress.
> + */
> + if (!host->data)
> + return;
> +
> + bcm2835_check_data_error(host, intmask);
> + if (host->data->error)
> + goto finished;
> +
> + if (host->data->flags & MMC_DATA_WRITE) {
> + /* Use the block interrupt for writes after the first block */
> + host->hcfg &= ~(SDHCFG_DATA_IRPT_EN);
> + host->hcfg |= SDHCFG_BLOCK_IRPT_EN;
> + writel(host->hcfg, host->ioaddr + SDHCFG);
> + bcm2835_transfer_pio(host);
> + } else {
> + bcm2835_transfer_pio(host);
> + host->blocks--;
> + if ((host->blocks == 0) || host->data->error)
> + goto finished;
> + }
> + return;
> +
> +finished:
> + host->hcfg &= ~(SDHCFG_DATA_IRPT_EN | SDHCFG_BLOCK_IRPT_EN);
> + writel(host->hcfg, host->ioaddr + SDHCFG);
> + return;
> +}
> +
> +static void bcm2835_data_threaded_irq(struct bcm2835_host *host)
> +{
> + if (!host->data)
> + return;
> + if ((host->blocks == 0) || host->data->error)
> + bcm2835_finish_data(host);
> +}
> +
> +static void bcm2835_block_irq(struct bcm2835_host *host)
> +{
> + if (WARN_ON(!host->data)) {
> + bcm2835_dumpregs(host);
> + return;
> + }
> +
> + if (!host->dma_desc) {
> + WARN_ON(!host->blocks);
> + if (host->data->error || (--host->blocks == 0))
> + bcm2835_finish_data(host);
> + else
> + bcm2835_transfer_pio(host);
> + } else if (host->data->flags & MMC_DATA_WRITE) {
> + bcm2835_finish_data(host);
> + }
> +}
> +
> +static irqreturn_t bcm2835_irq(int irq, void *dev_id)
> +{
> + irqreturn_t result = IRQ_NONE;
> + struct bcm2835_host *host = dev_id;
> + u32 intmask;
> +
> + spin_lock(&host->lock);
> +
> + intmask = readl(host->ioaddr + SDHSTS);
> +
> + writel(SDHSTS_BUSY_IRPT |
> + SDHSTS_BLOCK_IRPT |
> + SDHSTS_SDIO_IRPT |
> + SDHSTS_DATA_FLAG,
> + host->ioaddr + SDHSTS);
> +
> + if (intmask & SDHSTS_BLOCK_IRPT) {
> + bcm2835_check_data_error(host, intmask);
> + host->irq_block = true;
> + result = IRQ_WAKE_THREAD;
> + }
> +
> + if (intmask & SDHSTS_BUSY_IRPT) {
> + if (!bcm2835_check_cmd_error(host, intmask)) {
> + host->irq_busy = true;
> + result = IRQ_WAKE_THREAD;
> + } else {
> + result = IRQ_HANDLED;
> + }
> + }
> +
> + /* There is no true data interrupt status bit, so it is
> + * necessary to qualify the data flag with the interrupt
> + * enable bit.
> + */
> + if ((intmask & SDHSTS_DATA_FLAG) &&
> + (host->hcfg & SDHCFG_DATA_IRPT_EN)) {
> + bcm2835_data_irq(host, intmask);
> + host->irq_data = true;
> + result = IRQ_WAKE_THREAD;
> + }
> +
> + spin_unlock(&host->lock);
> +
> + return result;
> +}
> +
> +static irqreturn_t bcm2835_threaded_irq(int irq, void *dev_id)
> +{
> + struct bcm2835_host *host = dev_id;
> + unsigned long flags;
> + bool block, busy, data;
> +
> + spin_lock_irqsave(&host->lock, flags);
> +
> + block = host->irq_block;
> + busy = host->irq_busy;
> + data = host->irq_data;
> + host->irq_block = false;
> + host->irq_busy = false;
> + host->irq_data = false;
> +
> + spin_unlock_irqrestore(&host->lock, flags);
> +
> + mutex_lock(&host->mutex);
> +
> + if (block)
> + bcm2835_block_irq(host);
> + if (busy)
> + bcm2835_busy_irq(host);
> + if (data)
> + bcm2835_data_threaded_irq(host);
> +
> + mutex_unlock(&host->mutex);
> +
> + return IRQ_HANDLED;
> +}
> +
> +void bcm2835_set_clock(struct bcm2835_host *host, unsigned int clock)
> +{
> + int div = 0; /* Initialized for compiler warning */
Init with zero (and the comment) shouldn't be necessary anymore.
> +
> + /* The SDCDIV register has 11 bits, and holds (div - 2). But
> + * in data mode the max is 50MHz wihout a minimum, and only
> + * the bottom 3 bits are used. Since the switch over is
> + * automatic (unless we have marked the card as slow...),
> + * chosen values have to make sense in both modes. Ident mode
> + * must be 100-400KHz, so can range check the requested
> + * clock. CMD15 must be used to return to data mode, so this
> + * can be monitored.
> + *
> + * clock 250MHz -> 0->125MHz, 1->83.3MHz, 2->62.5MHz, 3->50.0MHz
> + * 4->41.7MHz, 5->35.7MHz, 6->31.3MHz, 7->27.8MHz
> + *
> + * 623->400KHz/27.8MHz
> + * reset value (507)->491159/50MHz
> + *
> + * BUT, the 3-bit clock divisor in data mode is too small if
> + * the core clock is higher than 250MHz, so instead use the
> + * SLOW_CARD configuration bit to force the use of the ident
> + * clock divisor at all times.
> + */
> +
> + host->mmc->actual_clock = 0;
dito?
> +
> + if (clock < 100000) {
> + /* Can't stop the clock, but make it as slow as possible
> + * to show willing
> + */
> + host->cdiv = SDCDIV_MAX_CDIV;
> + writel(host->cdiv, host->ioaddr + SDCDIV);
> + return;
> + }
> +
> + div = host->max_clk / clock;
> + if (div < 2)
> + div = 2;
> + if ((host->max_clk / div) > clock)
> + div++;
> + div -= 2;
> +
> + if (div > SDCDIV_MAX_CDIV)
> + div = SDCDIV_MAX_CDIV;
> +
> + clock = host->max_clk / (div + 2);
> + host->mmc->actual_clock = clock;
> +
> + /* Calibrate some delays */
> +
> + host->ns_per_fifo_word = (1000000000 / clock) *
> + ((host->mmc->caps & MMC_CAP_4_BIT_DATA) ? 8 : 32);
> +
> + host->cdiv = div;
> + writel(host->cdiv, host->ioaddr + SDCDIV);
> +
> + /* Set the timeout to 500ms */
> + writel(host->mmc->actual_clock / 2, host->ioaddr + SDTOUT);
> +}
> +
> +static void bcm2835_request(struct mmc_host *mmc,
> + struct mmc_request *mrq)
> +{
> + struct bcm2835_host *host = mmc_priv(mmc);
> + struct device *dev = &host->pdev->dev;
> + u32 edm, fsm;
> +
> + /* Reset the error statuses in case this is a retry */
> + if (mrq->sbc)
> + mrq->sbc->error = 0;
> + if (mrq->cmd)
> + mrq->cmd->error = 0;
> + if (mrq->data)
> + mrq->data->error = 0;
> + if (mrq->stop)
> + mrq->stop->error = 0;
> +
> + if (mrq->data && !is_power_of_2(mrq->data->blksz)) {
> + dev_err(dev, "unsupported block size (%d bytes)\n",
> + mrq->data->blksz);
> + mrq->cmd->error = -EINVAL;
> + mmc_request_done(mmc, mrq);
> + return;
> + }
> +
> + if (host->use_dma && mrq->data &&
> + (mrq->data->blocks > host->pio_limit))
> + bcm2835_prepare_dma(host, mrq->data);
> +
> + mutex_lock(&host->mutex);
> +
> + WARN_ON(host->mrq);
> + host->mrq = mrq;
> +
> + edm = readl(host->ioaddr + SDEDM);
> + fsm = edm & SDEDM_FSM_MASK;
> +
> + if ((fsm != SDEDM_FSM_IDENTMODE) &&
> + (fsm != SDEDM_FSM_DATAMODE)) {
> + dev_err(dev, "previous command (%d) not complete (EDM %x)\n",
> + readl(host->ioaddr + SDCMD) & SDCMD_CMD_MASK,
> + edm);
> + bcm2835_dumpregs(host);
> + mrq->cmd->error = -EILSEQ;
> + bcm2835_finish_request(host);
> + mutex_unlock(&host->mutex);
> + return;
> + }
> +
> + host->use_sbc = !!mrq->sbc && (host->mrq->data->flags & MMC_DATA_READ);
> + if (host->use_sbc) {
> + if (bcm2835_send_command(host, mrq->sbc)) {
> + if (!host->use_busy)
> + bcm2835_finish_command(host);
> + }
> + } else if (bcm2835_send_command(host, mrq->cmd)) {
> + if (host->data && host->dma_desc) {
> + /* DMA transfer starts now, PIO starts after irq */
> + bcm2835_start_dma(host);
> + }
> +
> + if (!host->use_busy)
> + bcm2835_finish_command(host);
> + }
> +
> + mutex_unlock(&host->mutex);
> +}
> +
> +static void bcm2835_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> +{
> + struct bcm2835_host *host = mmc_priv(mmc);
> +
> + mutex_lock(&host->mutex);
> +
> + if (!ios->clock || ios->clock != host->clock) {
> + bcm2835_set_clock(host, ios->clock);
> + host->clock = ios->clock;
> + }
> +
> + /* set bus width */
> + host->hcfg &= ~SDHCFG_WIDE_EXT_BUS;
> + if (ios->bus_width == MMC_BUS_WIDTH_4)
> + host->hcfg |= SDHCFG_WIDE_EXT_BUS;
> +
> + host->hcfg |= SDHCFG_WIDE_INT_BUS;
> +
> + /* Disable clever clock switching, to cope with fast core clocks */
> + host->hcfg |= SDHCFG_SLOW_CARD;
> +
> + writel(host->hcfg, host->ioaddr + SDHCFG);
> +
> + mutex_unlock(&host->mutex);
> +}
> +
> +static struct mmc_host_ops bcm2835_ops = {
> + .request = bcm2835_request,
> + .set_ios = bcm2835_set_ios,
> + .hw_reset = bcm2835_reset,
> +};
> +
> +static void bcm2835_finish_request(struct bcm2835_host *host)
> +{
> + struct dma_chan *terminate_chan = NULL;
> + struct mmc_request *mrq;
> +
> + cancel_delayed_work(&host->timeout_work);
> +
> + mrq = host->mrq;
> +
> + host->mrq = NULL;
> + host->cmd = NULL;
> + host->data = NULL;
> +
> + host->dma_desc = NULL;
> + terminate_chan = host->dma_chan;
> + host->dma_chan = NULL;
> +
> + if (terminate_chan) {
> + int err = dmaengine_terminate_all(terminate_chan);
> +
> + if (err)
> + dev_err(&host->pdev->dev,
> + "failed to terminate DMA (%d)\n", err);
> + }
> +
> + mmc_request_done(host->mmc, mrq);
> +}
> +
> +int bcm2835_add_host(struct bcm2835_host *host)
> +{
> + struct mmc_host *mmc = host->mmc;
> + struct device *dev = &host->pdev->dev;
> + struct dma_slave_config cfg;
> + char pio_limit_string[20];
> + int ret;
> +
> + bcm2835_reset_internal(host);
> +
> + mmc->f_max = host->max_clk;
> + mmc->f_min = host->max_clk / SDCDIV_MAX_CDIV;
> +
> + mmc->max_busy_timeout = ~0 / (mmc->f_max / 1000);
> +
> + dev_dbg(dev, "f_max %d, f_min %d, max_busy_timeout %d\n",
> + mmc->f_max, mmc->f_min, mmc->max_busy_timeout);
> +
> + /* host controller capabilities */
> + mmc->caps |= MMC_CAP_SD_HIGHSPEED | MMC_CAP_MMC_HIGHSPEED |
> + MMC_CAP_NEEDS_POLL | MMC_CAP_HW_RESET | MMC_CAP_ERASE |
> + MMC_CAP_CMD23;
> +
> + spin_lock_init(&host->lock);
> + mutex_init(&host->mutex);
> +
> + if (IS_ERR_OR_NULL(host->dma_chan_tx) ||
> + IS_ERR_OR_NULL(host->dma_chan_rx)) {
> + dev_err(dev, "unable to initialise DMA channels. Falling back to PIO\n");
> + host->use_dma = false;
> + } else {
> + host->use_dma = true;
> +
> + cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> + cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> + cfg.slave_id = 13; /* DREQ channel */
> +
> + cfg.direction = DMA_MEM_TO_DEV;
> + cfg.src_addr = 0;
> + cfg.dst_addr = host->phys_addr + SDDATA;
> + ret = dmaengine_slave_config(host->dma_chan_tx, &cfg);
> + if (ret)
> + host->use_dma = false;
> +
> + cfg.direction = DMA_DEV_TO_MEM;
> + cfg.src_addr = host->phys_addr + SDDATA;
> + cfg.dst_addr = 0;
> + ret = dmaengine_slave_config(host->dma_chan_rx, &cfg);
> + if (ret)
> + host->use_dma = false;
> + }
> +
> + mmc->max_segs = 128;
> + mmc->max_req_size = 524288;
> + mmc->max_seg_size = mmc->max_req_size;
> + mmc->max_blk_size = 512;
I will try to test the possible values on a compute module.
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