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Message-ID: <50CF393F.4040009@gmail.com>
Date: Mon, 17 Dec 2012 09:24:47 -0600
From: Rob Herring <robherring2@...il.com>
To: Laxman Dewangan <ldewangan@...dia.com>
CC: alan@...ux.intel.com, gregkh@...uxfoundation.org, jslaby@...e.cz,
grant.likely@...retlab.ca, devicetree-discuss@...ts.ozlabs.org,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-serial@...r.kernel.org, linux-tegra@...r.kernel.org,
swarren@...dotorg.org
Subject: Re: [PATCH] serial: tegra: add serial driver
On 12/17/2012 06:10 AM, Laxman Dewangan wrote:
> Nvidia's Tegra has multiple uart controller which supports:
> - APB dma based controller fifo read/write.
> - End Of Data interrupt in incoming data to know whether end
> of frame achieve or not.
> - Hw controlled RTS and CTS flow control to reduce SW overhead.
>
> Add serial driver to use all above feature.
>
> Signed-off-by: Laxman Dewangan <ldewangan@...dia.com>
> ---
> .../bindings/serial/nvidia,serial-tegra.txt | 26 +
Can we have a name without a comma. If serial-tegra is specific enough
for the kernel, then it is for the binding doc too.
> drivers/tty/serial/Kconfig | 14 +
> drivers/tty/serial/Makefile | 1 +
> drivers/tty/serial/serial_tegra.c | 1398 ++++++++++++++++++++
> include/linux/serial_tegra.h | 33 +
> 5 files changed, 1472 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/serial/nvidia,serial-tegra.txt
> create mode 100644 drivers/tty/serial/serial_tegra.c
> create mode 100644 include/linux/serial_tegra.h
>
> diff --git a/Documentation/devicetree/bindings/serial/nvidia,serial-tegra.txt b/Documentation/devicetree/bindings/serial/nvidia,serial-tegra.txt
> new file mode 100644
> index 0000000..fc5803b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/serial/nvidia,serial-tegra.txt
> @@ -0,0 +1,26 @@
> +NVIDIA Tegra20/Tegra30 high speed (dma based) UART controller driver.
> +
> +Required properties:
> +- compatible : should be "nvidia,tegra20-hsuart", "nvidia,tegra30-hsuart".
> +- reg: Should contain UART controller registers location and length.
> +- interrupts: Should contain UART controller interrupts.
> +- nvidia,dma-request-selector : The Tegra DMA controller's phandle and
> + request selector for this UART controller.
This should use the generic DMA binding although I'm not sure if that
made it into 3.8.
> +- port-number: Uart port number for /dev/ttyHSx where x is port number.
Use aliases like other platforms like i.MX have done.
> +Optional properties:
> +- nvidia,enable-modem-interrupt: Enable modem interrupts. Should be enable
s/enable/enabled/ on the last one.
> + only if all 8 lines of uart controller is pinmuxed.
s/is/are/
> +
> +Example:
> +
> +serial@...06000 {
> + compatible = "nvidia,tegra30-hsuart", "nvidia,tegra20-hsuart";
> + reg = <0x70006000 0x40>;
> + reg-shift = <2>;
> + interrupts = <0 36 0x04>;
> + port-number = <0>;
> + nvidia,dma-request-selector = <&apbdma 8>;
> + nvidia,enable-modem-interrupt;
> + status = "disabled";
> +};
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index 59c23d0..57dbbc1 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -269,6 +269,20 @@ config SERIAL_SIRFSOC_CONSOLE
> your boot loader about how to pass options to the kernel at
> boot time.)
>
> +config SERIAL_SAMSUNG_UARTS_4
> + bool
Huh?
> +
> +config SERIAL_TEGRA
> + tristate "Nvidia Tegra20/30 SoC serial controller"
> + depends on ARCH_TEGRA && TEGRA20_APB_DMA
> + select SERIAL_CORE
> + help
> + Support for the on-chip UARTs on the Nvidia Tegra seria SOCs
> + providing /dev/ttyHS0, 1, 2, 3 and 4 (note, some machines may not
> + provide all of these ports, depending on how the serial port
> + are enabled). This driver uses the APB dma to achieve higher baudrate
> + and better performance.
> +
> config SERIAL_MAX3100
> tristate "MAX3100 support"
> depends on SPI
> diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
> index df1b998..73fb688 100644
> --- a/drivers/tty/serial/Makefile
> +++ b/drivers/tty/serial/Makefile
> @@ -80,6 +80,7 @@ obj-$(CONFIG_SERIAL_MXS_AUART) += mxs-auart.o
> obj-$(CONFIG_SERIAL_LANTIQ) += lantiq.o
> obj-$(CONFIG_SERIAL_XILINX_PS_UART) += xilinx_uartps.o
> obj-$(CONFIG_SERIAL_SIRFSOC) += sirfsoc_uart.o
> +obj-$(CONFIG_SERIAL_TEGRA) += serial_tegra.o
> obj-$(CONFIG_SERIAL_AR933X) += ar933x_uart.o
> obj-$(CONFIG_SERIAL_EFM32_UART) += efm32-uart.o
> obj-$(CONFIG_SERIAL_ARC) += arc_uart.o
> diff --git a/drivers/tty/serial/serial_tegra.c b/drivers/tty/serial/serial_tegra.c
> new file mode 100644
> index 0000000..791cf35
> --- /dev/null
> +++ b/drivers/tty/serial/serial_tegra.c
> @@ -0,0 +1,1398 @@
> +/*
> + * serial_tegra.c
> + *
> + * High-speed serial driver for NVIDIA Tegra SoCs
> + *
> + * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
> + *
> + * Author: Laxman Dewangan <ldewangan@...dia.com>
> + *
> + * 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/debugfs.h>
> +#include <linux/delay.h>
> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/dmapool.h>
> +#include <linux/io.h>
> +#include <linux/irq.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/pagemap.h>
> +#include <linux/platform_device.h>
> +#include <linux/serial.h>
> +#include <linux/serial_8250.h>
> +#include <linux/serial_core.h>
> +#include <linux/serial_reg.h>
> +#include <linux/slab.h>
> +#include <linux/string.h>
> +#include <linux/serial_tegra.h>
> +#include <linux/termios.h>
> +#include <linux/tty_flip.h>
> +
> +#include <mach/clk.h>
> +
> +#define TEGRA_UART_TYPE "TEGRA_UART"
> +#define TX_EMPTY_STATUS (UART_LSR_TEMT | UART_LSR_THRE)
> +#define BYTES_TO_ALIGN(x) ((unsigned long)(x) & 0x3)
> +
> +#define TEGRA_UART_RX_DMA_BUFFER_SIZE 4096
> +#define TEGRA_UART_LSR_TXFIFO_FULL 0x100
> +#define TEGRA_UART_IER_EORD 0x20
> +#define TEGRA_UART_MCR_RTS_EN 0x40
> +#define TEGRA_UART_MCR_CTS_EN 0x20
> +#define TEGRA_UART_LSR_ANY (UART_LSR_OE | UART_LSR_BI | \
> + UART_LSR_PE | UART_LSR_FE)
> +#define TEGRA_UART_IRDA_CSR 0x08
> +#define TEGRA_UART_SIR_ENABLED 0x80
> +
> +#define TEGRA_UART_TX_PIO 1
> +#define TEGRA_UART_TX_DMA 2
> +#define TEGRA_UART_MIN_DMA 16
> +#define TEGRA_UART_FIFO_SIZE 32
> +
> +/*
> + * Tx fifo trigger level setting in tegra uart is in
> + * reverse way then conventional uart.
> + */
> +#define TEGRA_UART_TX_TRIG_16B 0x00
> +#define TEGRA_UART_TX_TRIG_8B 0x10
> +#define TEGRA_UART_TX_TRIG_4B 0x20
> +#define TEGRA_UART_TX_TRIG_1B 0x30
> +
> +#define TEGRA_UART_MAXIMUM 5
> +
> +/* Default UART setting when started: 115200 no parity, stop, 8 data bits */
> +#define TEGRA_UART_DEFAULT_BAUD 115200
> +#define TEGRA_UART_DEFAULT_LSR UART_LCR_WLEN8
> +
> +/* Tx transfer mode */
> +#define TEGRA_TX_PIO 1
> +#define TEGRA_TX_DMA 2
> +
> +/**
> + * tegra_uart_chip_data: SOC specific data.
> + *
> + * @tx_fifo_full_status: Status flag available for checking tx fifo full.
> + * @allow_txfifo_reset_fifo_mode: allow_tx fifo reset with fifo mode or not.
> + * Tegra30 does not allow this.
> + * @support_clk_src_div: Clock source support the clock divider.
> + */
> +struct tegra_uart_chip_data {
> + bool tx_fifo_full_status;
> + bool allow_txfifo_reset_fifo_mode;
> + bool support_clk_src_div;
> +};
> +
> +struct tegra_uart_chip_data tegra20_uart_chip_data = {
> + .tx_fifo_full_status = false,
> + .allow_txfifo_reset_fifo_mode = true,
> + .support_clk_src_div = false,
> +};
> +
> +struct tegra_uart_chip_data tegra30_uart_chip_data = {
> + .tx_fifo_full_status = true,
> + .allow_txfifo_reset_fifo_mode = false,
> + .support_clk_src_div = true,
> +};
> +
> +struct tegra_uart_port {
> + struct uart_port uport;
> + const struct tegra_uart_chip_data *cdata;
> +
> + struct clk *uart_clk;
> + unsigned int current_baud;
> +
> + /* Register shadow */
> + unsigned long fcr_shadow;
> + unsigned long mcr_shadow;
> + unsigned long lcr_shadow;
> + unsigned long ier_shadow;
> + bool rts_active;
> +
> + int tx_in_progress;
> + unsigned int tx_bytes;
> +
> + int enable_modem_interrupt;
> +
> + bool rx_timeout;
> + int rx_in_progress;
> + int symb_bit;
> + int dma_req_sel;
> +
> + struct dma_chan *rx_dma_chan;
> + struct dma_chan *tx_dma_chan;
> + dma_addr_t rx_dma_buf_phys;
> + dma_addr_t tx_dma_buf_phys;
> + unsigned char *rx_dma_buf_virt;
> + unsigned char *tx_dma_buf_virt;
> + struct dma_async_tx_descriptor *tx_dma_desc;
> + struct dma_async_tx_descriptor *rx_dma_desc;
> + dma_cookie_t tx_cookie;
> + dma_cookie_t rx_cookie;
> + int tx_bytes_requested;
> + int rx_bytes_requested;
> +};
> +
> +static void tegra_uart_start_next_tx(struct tegra_uart_port *tup);
> +static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup);
> +
> +static inline unsigned long tegra_uart_read(struct tegra_uart_port *tup,
> + unsigned long reg)
> +{
> + return readl(tup->uport.membase + (reg << tup->uport.regshift));
> +}
> +
> +static inline void tegra_uart_write(struct tegra_uart_port *tup, unsigned val,
> + unsigned long reg)
> +{
> + writel(val, tup->uport.membase + (reg << tup->uport.regshift));
> +}
> +
> +static inline struct tegra_uart_port *to_tegra_uport(struct uart_port *u)
> +{
> + return container_of(u, struct tegra_uart_port, uport);
> +}
> +
> +static unsigned int tegra_uart_get_mctrl(struct uart_port *u)
> +{
> + struct tegra_uart_port *tup = to_tegra_uport(u);
> +
> + /*
> + * RI - Ring detector is active
> + * CD/DCD/CAR - Carrier detect is always active. For some reason
> + * linux has different names for carrier detect.
> + * DSR - Data Set ready is active as the hardware doesn't support it.
> + * Don't know if the linux support this yet?
> + * CTS - Clear to send. Always set to active, as the hardware handles
> + * CTS automatically.
> + */
> + if (tup->enable_modem_interrupt)
> + return TIOCM_RI | TIOCM_CD | TIOCM_DSR | TIOCM_CTS;
> + return TIOCM_CTS;
> +}
> +
> +static void set_rts(struct tegra_uart_port *tup, bool active)
> +{
> + unsigned long mcr;
> +
> + mcr = tup->mcr_shadow;
> + if (active)
> + mcr |= TEGRA_UART_MCR_RTS_EN;
> + else
> + mcr &= ~TEGRA_UART_MCR_RTS_EN;
> + if (mcr != tup->mcr_shadow) {
> + tegra_uart_write(tup, mcr, UART_MCR);
> + tup->mcr_shadow = mcr;
> + }
> + return;
> +}
> +
> +static void set_dtr(struct tegra_uart_port *tup, bool active)
> +{
> + unsigned long mcr;
> +
> + mcr = tup->mcr_shadow;
> + if (active)
> + mcr |= UART_MCR_DTR;
> + else
> + mcr &= ~UART_MCR_DTR;
> + if (mcr != tup->mcr_shadow) {
> + tegra_uart_write(tup, mcr, UART_MCR);
> + tup->mcr_shadow = mcr;
> + }
> + return;
> +}
> +
> +static void tegra_uart_set_mctrl(struct uart_port *u, unsigned int mctrl)
> +{
> + struct tegra_uart_port *tup = to_tegra_uport(u);
> + unsigned long mcr;
> +
> + mcr = tup->mcr_shadow;
> + if (mctrl & TIOCM_RTS) {
> + tup->rts_active = true;
> + set_rts(tup, true);
> + } else {
> + tup->rts_active = false;
> + set_rts(tup, false);
> + }
> +
> + if (mctrl & TIOCM_DTR)
> + set_dtr(tup, true);
> + else
> + set_dtr(tup, false);
> + return;
> +}
> +
> +static void tegra_uart_break_ctl(struct uart_port *u, int break_ctl)
> +{
> + struct tegra_uart_port *tup = to_tegra_uport(u);
> + unsigned long lcr;
> +
> + lcr = tup->lcr_shadow;
> + if (break_ctl)
> + lcr |= UART_LCR_SBC;
> + else
> + lcr &= ~UART_LCR_SBC;
> + tegra_uart_write(tup, lcr, UART_LCR);
> + tup->lcr_shadow = lcr;
> +}
> +
> +/* Wait for a symbol-time. */
> +static void tegra_uart_wait_sym_time(struct tegra_uart_port *tup,
> + unsigned int syms)
> +{
> + if (tup->current_baud)
> + udelay(DIV_ROUND_UP(syms * tup->symb_bit * 1000000,
> + tup->current_baud));
> +}
> +
> +static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits)
> +{
> + unsigned long fcr = tup->fcr_shadow;
> +
> + if (tup->cdata->allow_txfifo_reset_fifo_mode) {
> + fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
> + tegra_uart_write(tup, fcr, UART_FCR);
> + } else {
> + fcr &= ~UART_FCR_ENABLE_FIFO;
> + tegra_uart_write(tup, fcr, UART_FCR);
> + udelay(60);
> + fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
> + tegra_uart_write(tup, fcr, UART_FCR);
> + fcr |= UART_FCR_ENABLE_FIFO;
> + tegra_uart_write(tup, fcr, UART_FCR);
> + }
> +
> + /* Dummy read to ensure the write is posted */
> + tegra_uart_read(tup, UART_SCR);
> +
> + /* Wait for the flush to propagate. */
> + tegra_uart_wait_sym_time(tup, 1);
> +}
> +
> +static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud)
> +{
> + unsigned long rate;
> + unsigned int divisor;
> + unsigned long lcr;
> + int ret;
> +
> + if (tup->current_baud == baud)
> + return 0;
> +
> + if (tup->cdata->support_clk_src_div) {
> + rate = baud * 16;
> + ret = clk_set_rate(tup->uart_clk, rate);
> + if (ret < 0) {
> + dev_err(tup->uport.dev,
> + "clk_set_rate() failed for rate %lu\n", rate);
> + return ret;
> + }
> + divisor = 1;
> + } else {
> + rate = clk_get_rate(tup->uart_clk);
> + divisor = DIV_ROUND_CLOSEST(rate, baud * 16);
> + }
> +
> + lcr = tup->lcr_shadow;
> + lcr |= UART_LCR_DLAB;
> + tegra_uart_write(tup, lcr, UART_LCR);
> +
> + tegra_uart_write(tup, divisor & 0xFF, UART_TX);
> + tegra_uart_write(tup, ((divisor >> 8) & 0xFF), UART_IER);
> +
> + lcr &= ~UART_LCR_DLAB;
> + tegra_uart_write(tup, lcr, UART_LCR);
> +
> + /* Dummy read to ensure the write is posted */
> + tegra_uart_read(tup, UART_SCR);
> +
> + tup->current_baud = baud;
> +
> + /* wait two character intervals at new rate */
> + tegra_uart_wait_sym_time(tup, 2);
> + return 0;
> +}
> +
> +static char tegra_uart_decode_rx_error(struct tegra_uart_port *tup,
> + unsigned long lsr)
> +{
> + char flag = TTY_NORMAL;
> +
> + if (unlikely(lsr & TEGRA_UART_LSR_ANY)) {
> + if (lsr & UART_LSR_OE) {
> + /* Overrrun error */
> + flag |= TTY_OVERRUN;
> + tup->uport.icount.overrun++;
> + dev_err(tup->uport.dev, "Got overrun errors\n");
> + } else if (lsr & UART_LSR_PE) {
> + /* Parity error */
> + flag |= TTY_PARITY;
> + tup->uport.icount.parity++;
> + dev_err(tup->uport.dev, "Got Parity errors\n");
> + } else if (lsr & UART_LSR_FE) {
> + flag |= TTY_FRAME;
> + tup->uport.icount.frame++;
> + dev_err(tup->uport.dev, "Got frame errors\n");
> + } else if (lsr & UART_LSR_BI) {
> + dev_err(tup->uport.dev, "Got Break\n");
> + tup->uport.icount.brk++;
> + /* If FIFO read error without any data, reset Rx FIFO */
> + if (!(lsr & UART_LSR_DR) && (lsr & UART_LSR_FIFOE))
> + tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_RCVR);
> + }
> + }
> + return flag;
> +}
> +
> +static int tegra_uart_request_port(struct uart_port *u)
> +{
> + return 0;
> +}
> +
> +static void tegra_uart_release_port(struct uart_port *u)
> +{
> + /* Nothing to do here */
> +}
> +
> +static void tegra_uart_fill_tx_fifo(struct tegra_uart_port *tup, int max_bytes)
> +{
> + struct circ_buf *xmit = &tup->uport.state->xmit;
> + int i;
> +
> + for (i = 0; i < max_bytes; i++) {
> + BUG_ON(uart_circ_empty(xmit));
> + if (tup->cdata->tx_fifo_full_status) {
> + unsigned long lsr = tegra_uart_read(tup, UART_LSR);
> + if ((lsr & TEGRA_UART_LSR_TXFIFO_FULL))
> + break;
> + }
> + tegra_uart_write(tup, xmit->buf[xmit->tail], UART_TX);
> + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
> + tup->uport.icount.tx++;
> + }
> +}
> +
> +static void tegra_uart_start_pio_tx(struct tegra_uart_port *tup,
> + unsigned int bytes)
> +{
> + if (bytes > TEGRA_UART_MIN_DMA)
> + bytes = TEGRA_UART_MIN_DMA;
> +
> + tup->tx_in_progress = TEGRA_UART_TX_PIO;
> + tup->tx_bytes = bytes;
> + tup->ier_shadow |= UART_IER_THRI;
> + tegra_uart_write(tup, tup->ier_shadow, UART_IER);
> +}
> +
> +static void tegra_uart_tx_dma_complete(void *args)
> +{
> + struct tegra_uart_port *tup = args;
> + struct circ_buf *xmit = &tup->uport.state->xmit;
> + struct dma_tx_state state;
> + unsigned long flags;
> + int count;
> +
> + dmaengine_tx_status(tup->tx_dma_chan, tup->rx_cookie, &state);
> + count = tup->tx_bytes_requested - state.residue;
> + async_tx_ack(tup->tx_dma_desc);
> + spin_lock_irqsave(&tup->uport.lock, flags);
> + xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
> + tup->tx_in_progress = 0;
> + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
> + uart_write_wakeup(&tup->uport);
> + tegra_uart_start_next_tx(tup);
> + spin_unlock_irqrestore(&tup->uport.lock, flags);
> +}
> +
> +static int tegra_uart_start_tx_dma(struct tegra_uart_port *tup,
> + unsigned long count)
> +{
> + struct circ_buf *xmit = &tup->uport.state->xmit;
> + dma_addr_t tx_phys_addr;
> +
> + dma_sync_single_for_device(tup->uport.dev, tup->tx_dma_buf_phys,
> + UART_XMIT_SIZE, DMA_TO_DEVICE);
> +
> + tup->tx_bytes = count & ~(0xF);
> + tx_phys_addr = tup->tx_dma_buf_phys + xmit->tail;
> + tup->tx_dma_desc = dmaengine_prep_slave_single(tup->tx_dma_chan,
> + tx_phys_addr, tup->tx_bytes, DMA_MEM_TO_DEV,
> + DMA_PREP_INTERRUPT);
> + if (!tup->tx_dma_desc) {
> + dev_err(tup->uport.dev, "Not able to get desc for Tx\n");
> + return -EIO;
> + }
> +
> + tup->tx_dma_desc->callback = tegra_uart_tx_dma_complete;
> + tup->tx_dma_desc->callback_param = tup;
> + tup->tx_in_progress = TEGRA_UART_TX_DMA;
> + tup->tx_bytes_requested = tup->tx_bytes;
> + tup->tx_cookie = dmaengine_submit(tup->tx_dma_desc);
> + dma_async_issue_pending(tup->tx_dma_chan);
> + return 0;
> +}
> +
> +static void tegra_uart_start_next_tx(struct tegra_uart_port *tup)
> +{
> + unsigned long tail;
> + unsigned long count;
> + struct circ_buf *xmit = &tup->uport.state->xmit;
> +
> + tail = (unsigned long)&xmit->buf[xmit->tail];
> + count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
> + if (!count)
> + return;
> +
> + if (count < TEGRA_UART_MIN_DMA)
> + tegra_uart_start_pio_tx(tup, count);
> + else if (BYTES_TO_ALIGN(tail) > 0)
> + tegra_uart_start_pio_tx(tup, BYTES_TO_ALIGN(tail));
> + else
> + tegra_uart_start_tx_dma(tup, count);
> +}
> +
> +/* Called by serial core driver with u->lock taken. */
> +static void tegra_uart_start_tx(struct uart_port *u)
> +{
> + struct tegra_uart_port *tup = to_tegra_uport(u);
> + struct circ_buf *xmit = &u->state->xmit;
> +
> + if (!uart_circ_empty(xmit) && !tup->tx_in_progress)
> + tegra_uart_start_next_tx(tup);
> +}
> +
> +static unsigned int tegra_uart_tx_empty(struct uart_port *u)
> +{
> + struct tegra_uart_port *tup = to_tegra_uport(u);
> + unsigned int ret = 0;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&u->lock, flags);
> + if (!tup->tx_in_progress) {
> + unsigned long lsr = tegra_uart_read(tup, UART_LSR);
> + if ((lsr & TX_EMPTY_STATUS) == TX_EMPTY_STATUS)
> + ret = TIOCSER_TEMT;
> + }
> + spin_unlock_irqrestore(&u->lock, flags);
> + return ret;
> +}
> +
> +static void tegra_uart_stop_tx(struct uart_port *u)
> +{
> + struct tegra_uart_port *tup = to_tegra_uport(u);
> + struct circ_buf *xmit = &tup->uport.state->xmit;
> + struct dma_tx_state state;
> + int count;
> +
> + dmaengine_terminate_all(tup->tx_dma_chan);
> + dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
> + count = tup->tx_bytes_requested - state.residue;
> + async_tx_ack(tup->tx_dma_desc);
> + xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
> + tup->tx_in_progress = 0;
> + return;
> +}
> +
> +static void tegra_uart_handle_tx_pio(struct tegra_uart_port *tup)
> +{
> + struct circ_buf *xmit = &tup->uport.state->xmit;
> +
> + tegra_uart_fill_tx_fifo(tup, tup->tx_bytes);
> + tup->tx_in_progress = 0;
> + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
> + uart_write_wakeup(&tup->uport);
> + tegra_uart_start_next_tx(tup);
> + return;
> +}
> +
> +static void tegra_uart_handle_rx_pio(struct tegra_uart_port *tup)
> +{
> + do {
> + char flag = TTY_NORMAL;
> + unsigned long lsr = 0;
> + unsigned char ch;
> +
> + lsr = tegra_uart_read(tup, UART_LSR);
> + if (!(lsr & UART_LSR_DR))
> + break;
> +
> + flag = tegra_uart_decode_rx_error(tup, lsr);
> + ch = (unsigned char) tegra_uart_read(tup, UART_RX);
> + tup->uport.icount.rx++;
> +
> + if (!uart_handle_sysrq_char(&tup->uport, ch))
> + uart_insert_char(&tup->uport, lsr,
> + UART_LSR_OE, ch, flag);
> + } while (1);
> +
> + return;
> +}
> +
> +static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup, int count)
> +{
> + int copied;
> +
> + tup->uport.icount.rx += count;
> + dma_sync_single_for_cpu(tup->uport.dev, tup->rx_dma_buf_phys,
> + TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
> + copied = tty_insert_flip_string(tup->uport.state->port.tty,
> + ((unsigned char *)(tup->rx_dma_buf_virt)), count);
> + if (copied != count) {
> + WARN_ON(1);
> + dev_err(tup->uport.dev, "RxData copy to tty layer failed\n");
> + }
> + dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
> + TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_TO_DEVICE);
> +}
> +
> +static void tegra_uart_rx_dma_complete(void *args)
> +{
> + struct tegra_uart_port *tup = args;
> + struct uart_port *u = &tup->uport;
> + int count = tup->rx_bytes_requested;
> + unsigned long flags;
> +
> + async_tx_ack(tup->rx_dma_desc);
> + spin_lock_irqsave(&u->lock, flags);
> +
> + /* Deactivate flow control to stop sender */
> + if (tup->rts_active)
> + set_rts(tup, false);
> +
> + /* If we are here, DMA is stopped */
> + if (count)
> + tegra_uart_copy_rx_to_tty(tup, count);
> +
> + tegra_uart_handle_rx_pio(tup);
> + tty_flip_buffer_push(u->state->port.tty);
> + tegra_uart_start_rx_dma(tup);
> +
> + /* Activate flow control to start transfer */
> + if (tup->rts_active)
> + set_rts(tup, true);
> +
> + spin_unlock_irqrestore(&u->lock, flags);
> +}
> +
> +static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup)
> +{
> + struct uart_port *u = &tup->uport;
> + struct dma_tx_state state;
> + int count;
> +
> + /* Deactivate flow control to stop sender */
> + if (tup->rts_active)
> + set_rts(tup, false);
> +
> + dmaengine_terminate_all(tup->rx_dma_chan);
> + dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
> + count = tup->rx_bytes_requested - state.residue;
> +
> + /* If we are here, DMA is stopped */
> + if (count)
> + tegra_uart_copy_rx_to_tty(tup, count);
> +
> + tegra_uart_handle_rx_pio(tup);
> + tty_flip_buffer_push(u->state->port.tty);
> + tegra_uart_start_rx_dma(tup);
> +
> + if (tup->rts_active)
> + set_rts(tup, true);
> +}
> +
> +static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup)
> +{
> + unsigned int count = TEGRA_UART_RX_DMA_BUFFER_SIZE;
> +
> + tup->rx_dma_desc = dmaengine_prep_slave_single(tup->rx_dma_chan,
> + tup->rx_dma_buf_phys, count, DMA_DEV_TO_MEM,
> + DMA_PREP_INTERRUPT);
> + if (!tup->rx_dma_desc) {
> + dev_err(tup->uport.dev, "Not able to get desc for Rx\n");
> + return -EIO;
> + }
> +
> + tup->rx_dma_desc->callback = tegra_uart_rx_dma_complete;
> + tup->rx_dma_desc->callback_param = tup;
> + dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
> + count, DMA_TO_DEVICE);
> + tup->rx_bytes_requested = count;
> + tup->rx_cookie = dmaengine_submit(tup->rx_dma_desc);
> + dma_async_issue_pending(tup->rx_dma_chan);
> + return 0;
> +}
> +
> +static void tegra_uart_handle_modem_signal_change(struct uart_port *u)
> +{
> + struct tegra_uart_port *tup = to_tegra_uport(u);
> + unsigned long msr;
> +
> + msr = tegra_uart_read(tup, UART_MSR);
> + if (!(msr & UART_MSR_ANY_DELTA))
> + return;
> +
> + if (msr & UART_MSR_TERI)
> + tup->uport.icount.rng++;
> + if (msr & UART_MSR_DDSR)
> + tup->uport.icount.dsr++;
> + /* We may only get DDCD when HW init and reset */
> + if (msr & UART_MSR_DDCD)
> + uart_handle_dcd_change(&tup->uport, msr & UART_MSR_DCD);
> + /* Will start/stop_tx accordingly */
> + if (msr & UART_MSR_DCTS)
> + uart_handle_cts_change(&tup->uport, msr & UART_MSR_CTS);
> + return;
> +}
> +
> +static irqreturn_t tegra_uart_isr(int irq, void *data)
> +{
> + struct tegra_uart_port *tup = data;
> + struct uart_port *u = &tup->uport;
> + unsigned long iir;
> + unsigned long ier;
> + bool is_rx_int = false;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&u->lock, flags);
> + while (1) {
> + iir = tegra_uart_read(tup, UART_IIR);
> + if (iir & UART_IIR_NO_INT) {
> + if (is_rx_int) {
> + tegra_uart_handle_rx_dma(tup);
> + if (tup->rx_in_progress) {
> + ier = tup->ier_shadow;
> + ier |= (UART_IER_RLSI | UART_IER_RTOIE |
> + TEGRA_UART_IER_EORD);
> + tup->ier_shadow = ier;
> + tegra_uart_write(tup, ier, UART_IER);
> + }
> + }
> + spin_unlock_irqrestore(&u->lock, flags);
> + return IRQ_HANDLED;
> + }
> +
> + switch ((iir >> 1) & 0x7) {
> + case 0: /* Modem signal change interrupt */
> + tegra_uart_handle_modem_signal_change(u);
> + break;
> +
> + case 1: /* Transmit interrupt only triggered when using PIO */
> + tup->ier_shadow &= ~UART_IER_THRI;
> + tegra_uart_write(tup, tup->ier_shadow, UART_IER);
> + tegra_uart_handle_tx_pio(tup);
> + break;
> +
> + case 4: /* End of data */
> + case 6: /* Rx timeout */
> + case 2: /* Receive */
> + if (!is_rx_int) {
> + is_rx_int = true;
> + /* Disable Rx interrupts */
> + ier = tup->ier_shadow;
> + ier |= UART_IER_RDI;
> + tegra_uart_write(tup, ier, UART_IER);
> + ier &= ~(UART_IER_RDI | UART_IER_RLSI |
> + UART_IER_RTOIE | TEGRA_UART_IER_EORD);
> + tup->ier_shadow = ier;
> + tegra_uart_write(tup, ier, UART_IER);
> + }
> + break;
> +
> + case 3: /* Receive error */
> + tegra_uart_decode_rx_error(tup,
> + tegra_uart_read(tup, UART_LSR));
> + break;
> +
> + case 5: /* break nothing to handle */
> + case 7: /* break nothing to handle */
> + break;
> + }
> + }
> +}
> +
> +static void tegra_uart_stop_rx(struct uart_port *u)
> +{
> + struct tegra_uart_port *tup = to_tegra_uport(u);
> + struct dma_tx_state state;
> + unsigned long ier;
> + int count;
> +
> + if (tup->rts_active)
> + set_rts(tup, false);
> +
> + if (!tup->rx_in_progress)
> + return;
> +
> + tegra_uart_wait_sym_time(tup, 1); /* wait a character interval */
> +
> + ier = tup->ier_shadow;
> + ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE |
> + TEGRA_UART_IER_EORD);
> + tup->ier_shadow = ier;
> + tegra_uart_write(tup, ier, UART_IER);
> + tup->rx_in_progress = 0;
> + if (tup->rx_dma_chan) {
> + dmaengine_terminate_all(tup->rx_dma_chan);
> + dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
> + async_tx_ack(tup->rx_dma_desc);
> + count = tup->rx_bytes_requested - state.residue;
> + tegra_uart_copy_rx_to_tty(tup, count);
> + tegra_uart_handle_rx_pio(tup);
> + } else {
> + tegra_uart_handle_rx_pio(tup);
> + }
> + tty_flip_buffer_push(u->state->port.tty);
> + return;
> +}
> +
> +static void tegra_uart_hw_deinit(struct tegra_uart_port *tup)
> +{
> + unsigned long flags;
> + unsigned long char_time = DIV_ROUND_UP(10000000, tup->current_baud);
> + unsigned long fifo_empty_time = tup->uport.fifosize * char_time;
> + unsigned long wait_time;
> + unsigned long lsr;
> + unsigned long msr;
> + unsigned long mcr;
> +
> + /* Disable interrupts */
> + tegra_uart_write(tup, 0, UART_IER);
> +
> + lsr = tegra_uart_read(tup, UART_LSR);
> + if ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
> + msr = tegra_uart_read(tup, UART_MSR);
> + mcr = tegra_uart_read(tup, UART_MCR);
> + if ((mcr & TEGRA_UART_MCR_CTS_EN) && (msr & UART_MSR_CTS))
> + dev_err(tup->uport.dev,
> + "Tx Fifo not empty, CTS disabled, waiting\n");
> +
> + /* Wait for Tx fifo to be empty */
> + while ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
> + wait_time = min(fifo_empty_time, 100lu);
> + udelay(wait_time);
> + fifo_empty_time -= wait_time;
> + if (!fifo_empty_time) {
> + msr = tegra_uart_read(tup, UART_MSR);
> + mcr = tegra_uart_read(tup, UART_MCR);
> + if ((mcr & TEGRA_UART_MCR_CTS_EN) &&
> + (msr & UART_MSR_CTS))
> + dev_err(tup->uport.dev,
> + "Slave not ready\n");
> + break;
> + }
> + lsr = tegra_uart_read(tup, UART_LSR);
> + }
> + }
> +
> + spin_lock_irqsave(&tup->uport.lock, flags);
> + /* Reset the Rx and Tx FIFOs */
> + tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR);
> + tup->current_baud = 0;
> + spin_unlock_irqrestore(&tup->uport.lock, flags);
> +
> + clk_disable_unprepare(tup->uart_clk);
> +}
> +
> +static int tegra_uart_hw_init(struct tegra_uart_port *tup)
> +{
> + int ret;
> +
> + tup->fcr_shadow = 0;
> + tup->mcr_shadow = 0;
> + tup->lcr_shadow = 0;
> + tup->ier_shadow = 0;
> + tup->current_baud = 0;
> +
> + clk_prepare_enable(tup->uart_clk);
> +
> + /* Reset the UART controller to clear all previous status.*/
> + tegra_periph_reset_assert(tup->uart_clk);
> + udelay(10);
> + tegra_periph_reset_deassert(tup->uart_clk);
> +
> + tup->rx_in_progress = 0;
> + tup->tx_in_progress = 0;
> +
> + /*
> + * Set the trigger level
> + *
> + * For PIO mode:
> + *
> + * For receive, this will interrupt the CPU after that many number of
> + * bytes are received, for the remaining bytes the receive timeout
> + * interrupt is received. Rx high watermark is set to 4.
> + *
> + * For transmit, if the trasnmit interrupt is enabled, this will
> + * interrupt the CPU when the number of entries in the FIFO reaches the
> + * low watermark. Tx low watermark is set to 16 bytes.
> + *
> + * For DMA mode:
> + *
> + * Set the Tx trigger to 16. This should match the DMA burst size that
> + * programmed in the DMA registers.
> + */
> + tup->fcr_shadow = UART_FCR_ENABLE_FIFO;
> + tup->fcr_shadow |= UART_FCR_R_TRIG_01;
> + tup->fcr_shadow |= TEGRA_UART_TX_TRIG_16B;
> + tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
> +
> + /*
> + * Initialize the UART with default configuration
> + * (115200, N, 8, 1) so that the receive DMA buffer may be
> + * enqueued
> + */
> + tup->lcr_shadow = TEGRA_UART_DEFAULT_LSR;
> + tegra_set_baudrate(tup, TEGRA_UART_DEFAULT_BAUD);
> + tup->fcr_shadow |= UART_FCR_DMA_SELECT;
> + tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
> +
> + ret = tegra_uart_start_rx_dma(tup);
> + if (ret < 0) {
> + dev_err(tup->uport.dev, "Not able to start Rx DMA\n");
> + return ret;
> + }
> + tup->rx_in_progress = 1;
> +
> + /*
> + * Enable IE_RXS for the receive status interrupts like line errros.
> + * Enable IE_RX_TIMEOUT to get the bytes which cannot be DMA'd.
> + *
> + * If using DMA mode, enable EORD instead of receive interrupt which
> + * will interrupt after the UART is done with the receive instead of
> + * the interrupt when the FIFO "threshold" is reached.
> + *
> + * EORD is different interrupt than RX_TIMEOUT - RX_TIMEOUT occurs when
> + * the DATA is sitting in the FIFO and couldn't be transferred to the
> + * DMA as the DMA size alignment(4 bytes) is not met. EORD will be
> + * triggered when there is a pause of the incomming data stream for 4
> + * characters long.
> + *
> + * For pauses in the data which is not aligned to 4 bytes, we get
> + * both the EORD as well as RX_TIMEOUT - SW sees RX_TIMEOUT first
> + * then the EORD.
> + */
> + tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | TEGRA_UART_IER_EORD;
> + tegra_uart_write(tup, tup->ier_shadow, UART_IER);
> + return 0;
> +}
> +
> +static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,
> + bool dma_to_memory)
> +{
> + struct dma_chan *dma_chan;
> + unsigned char *dma_buf;
> + dma_addr_t dma_phys;
> + int ret;
> + struct dma_slave_config dma_sconfig;
> + dma_cap_mask_t mask;
> +
> + dma_cap_zero(mask);
> + dma_cap_set(DMA_SLAVE, mask);
> + dma_chan = dma_request_channel(mask, NULL, NULL);
> + if (!dma_chan) {
> + dev_err(tup->uport.dev,
> + "Dma channel is not available, will try later\n");
> + return -EPROBE_DEFER;
> + }
> +
> + if (dma_to_memory) {
> + dma_buf = dma_alloc_coherent(tup->uport.dev,
> + TEGRA_UART_RX_DMA_BUFFER_SIZE,
> + &dma_phys, GFP_KERNEL);
> + if (!dma_buf) {
> + dev_err(tup->uport.dev,
> + "Not able to allocate the dma buffer\n");
> + dma_release_channel(dma_chan);
> + return -ENOMEM;
> + }
> + } else {
> + dma_phys = dma_map_single(tup->uport.dev,
> + tup->uport.state->xmit.buf, UART_XMIT_SIZE,
> + DMA_TO_DEVICE);
> + dma_buf = tup->uport.state->xmit.buf;
> + }
> +
> + dma_sconfig.slave_id = tup->dma_req_sel;
> + if (dma_to_memory) {
> + dma_sconfig.src_addr = tup->uport.mapbase;
> + dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> + dma_sconfig.src_maxburst = 4;
> + } else {
> + dma_sconfig.dst_addr = tup->uport.mapbase;
> + dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> + dma_sconfig.dst_maxburst = 16;
> + }
> +
> + ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
> + if (ret < 0) {
> + dev_err(tup->uport.dev,
> + "Dma slave config failed, err = %d\n", ret);
> + goto scrub;
> + }
> +
> + if (dma_to_memory) {
> + tup->rx_dma_chan = dma_chan;
> + tup->rx_dma_buf_virt = dma_buf;
> + tup->rx_dma_buf_phys = dma_phys;
> + } else {
> + tup->tx_dma_chan = dma_chan;
> + tup->tx_dma_buf_virt = dma_buf;
> + tup->tx_dma_buf_phys = dma_phys;
> + }
> + return 0;
> +
> +scrub:
> + dma_release_channel(dma_chan);
> + return ret;
> +}
> +
> +static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup,
> + bool dma_to_memory)
> +{
> + struct dma_chan *dma_chan;
> +
> + if (dma_to_memory) {
> + dma_free_coherent(tup->uport.dev, TEGRA_UART_RX_DMA_BUFFER_SIZE,
> + tup->rx_dma_buf_virt, tup->rx_dma_buf_phys);
> + dma_chan = tup->rx_dma_chan;
> + tup->rx_dma_chan = NULL;
> + tup->rx_dma_buf_phys = 0;
> + tup->rx_dma_buf_virt = NULL;
> + } else {
> + dma_unmap_single(tup->uport.dev, tup->tx_dma_buf_phys,
> + UART_XMIT_SIZE, DMA_TO_DEVICE);
> + dma_chan = tup->tx_dma_chan;
> + tup->tx_dma_chan = NULL;
> + tup->tx_dma_buf_phys = 0;
> + tup->tx_dma_buf_virt = NULL;
> + }
> + dma_release_channel(dma_chan);
> +}
> +
> +static int tegra_uart_startup(struct uart_port *u)
> +{
> + struct tegra_uart_port *tup = to_tegra_uport(u);
> + int ret;
> +
> + ret = tegra_uart_dma_channel_allocate(tup, false);
> + if (ret < 0) {
> + dev_err(u->dev, "Tx Dma allocation failed, err = %d\n", ret);
> + return ret;
> + }
> +
> + ret = tegra_uart_dma_channel_allocate(tup, true);
> + if (ret < 0) {
> + dev_err(u->dev, "Rx Dma allocation failed, err = %d\n", ret);
> + goto fail_rx_dma;
> + }
> +
> + ret = tegra_uart_hw_init(tup);
> + if (ret < 0) {
> + dev_err(u->dev, "Uart HW init failed, err = %d\n", ret);
> + goto fail_hw_init;
> + }
> +
> + ret = request_irq(u->irq, tegra_uart_isr, IRQF_DISABLED,
> + dev_name(u->dev), tup);
> + if (ret < 0) {
> + dev_err(u->dev, "Failed to register ISR for IRQ %d\n", u->irq);
> + goto fail_hw_init;
> + }
> + return 0;
> +
> +fail_hw_init:
> + tegra_uart_dma_channel_free(tup, true);
> +fail_rx_dma:
> + tegra_uart_dma_channel_free(tup, false);
> + return ret;
> +}
> +
> +static void tegra_uart_shutdown(struct uart_port *u)
> +{
> + struct tegra_uart_port *tup = to_tegra_uport(u);
> +
> + tegra_uart_hw_deinit(tup);
> +
> + tup->rx_in_progress = 0;
> + tup->tx_in_progress = 0;
> +
> + tegra_uart_dma_channel_free(tup, true);
> + tegra_uart_dma_channel_free(tup, false);
> + free_irq(u->irq, tup);
> +}
> +
> +static void tegra_uart_enable_ms(struct uart_port *u)
> +{
> + struct tegra_uart_port *tup = to_tegra_uport(u);
> +
> + if (tup->enable_modem_interrupt) {
> + tup->ier_shadow |= UART_IER_MSI;
> + tegra_uart_write(tup, tup->ier_shadow, UART_IER);
> + }
> +}
> +
> +static void tegra_uart_set_termios(struct uart_port *u,
> + struct ktermios *termios, struct ktermios *oldtermios)
> +{
> + struct tegra_uart_port *tup = to_tegra_uport(u);
> + unsigned int baud;
> + unsigned long flags;
> + unsigned int lcr;
> + unsigned int c_cflag = termios->c_cflag;
> + int symb_bit = 1;
> +
> + spin_lock_irqsave(&u->lock, flags);
> +
> + /* Changing configuration, it is safe to stop any rx now */
> + if (tup->rts_active)
> + set_rts(tup, false);
> +
> + /* Clear all interrupts as configuration is going to be change */
> + tegra_uart_write(tup, tup->ier_shadow | UART_IER_RDI, UART_IER);
> + tegra_uart_read(tup, UART_IER);
> + tegra_uart_write(tup, 0, UART_IER);
> + tegra_uart_read(tup, UART_IER);
> +
> + /* Parity */
> + lcr = tup->lcr_shadow;
> + lcr &= ~UART_LCR_PARITY;
> + if ((c_cflag & PARENB) == PARENB) {
> + symb_bit++;
> + if ((c_cflag & CMSPAR) == CMSPAR) {
> + dev_err(tup->uport.dev, "Space parity not supported\n");
> + return;
> + } else if (c_cflag & PARODD) {
> + lcr |= UART_LCR_PARITY;
> + lcr &= ~UART_LCR_EPAR;
> + lcr &= ~UART_LCR_SPAR;
> + } else {
> + lcr |= UART_LCR_PARITY;
> + lcr |= UART_LCR_EPAR;
> + lcr &= ~UART_LCR_SPAR;
> + }
> + }
> +
> + lcr &= ~UART_LCR_WLEN8;
> + switch (c_cflag & CSIZE) {
> + case CS5:
> + lcr |= UART_LCR_WLEN5;
> + symb_bit += 5;
> + break;
> + case CS6:
> + lcr |= UART_LCR_WLEN6;
> + symb_bit += 6;
> + break;
> + case CS7:
> + lcr |= UART_LCR_WLEN7;
> + symb_bit += 7;
> + break;
> + default:
> + lcr |= UART_LCR_WLEN8;
> + symb_bit += 8;
> + break;
> + }
> +
> + /* Stop bits */
> + if (termios->c_cflag & CSTOPB) {
> + lcr |= UART_LCR_STOP;
> + symb_bit += 2;
> + } else {
> + lcr &= ~UART_LCR_STOP;
> + symb_bit++;
> + }
> +
> + tegra_uart_write(tup, lcr, UART_LCR);
> + tup->lcr_shadow = lcr;
> + tup->symb_bit = symb_bit;
> +
> + /* Baud rate. */
> + baud = uart_get_baud_rate(u, termios, oldtermios, 200, 4000000);
> + spin_unlock_irqrestore(&u->lock, flags);
> + tegra_set_baudrate(tup, baud);
> + spin_lock_irqsave(&u->lock, flags);
> +
> + /* Flow control */
> + if (termios->c_cflag & CRTSCTS) {
> + tup->mcr_shadow |= TEGRA_UART_MCR_CTS_EN;
> + tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
> + tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
> + /* if top layer has asked to set rts active then do so here */
> + if (tup->rts_active)
> + set_rts(tup, true);
> + } else {
> + tup->mcr_shadow &= ~TEGRA_UART_MCR_CTS_EN;
> + tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
> + tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
> + }
> +
> + /* update the port timeout based on new settings */
> + uart_update_timeout(u, termios->c_cflag, baud);
> +
> + /* Make sure all write has completed */
> + tegra_uart_read(tup, UART_IER);
> +
> + /* Reenable interrupt */
> + tegra_uart_write(tup, tup->ier_shadow, UART_IER);
> + tegra_uart_read(tup, UART_IER);
> +
> + spin_unlock_irqrestore(&u->lock, flags);
> + return;
> +}
> +
> +/*
> + * Flush any TX data submitted for DMA and PIO. Called when the
> + * TX circular buffer is reset.
> + */
> +static void tegra_uart_flush_buffer(struct uart_port *u)
> +{
> + struct tegra_uart_port *tup = to_tegra_uport(u);
> +
> + tup->tx_bytes = 0;
> + if (tup->tx_dma_chan)
> + dmaengine_terminate_all(tup->tx_dma_chan);
> + return;
> +}
> +
> +static const char *tegra_uart_type(struct uart_port *u)
> +{
> + return TEGRA_UART_TYPE;
> +}
> +
> +static struct uart_ops tegra_uart_ops = {
> + .tx_empty = tegra_uart_tx_empty,
> + .set_mctrl = tegra_uart_set_mctrl,
> + .get_mctrl = tegra_uart_get_mctrl,
> + .stop_tx = tegra_uart_stop_tx,
> + .start_tx = tegra_uart_start_tx,
> + .stop_rx = tegra_uart_stop_rx,
> + .flush_buffer = tegra_uart_flush_buffer,
> + .enable_ms = tegra_uart_enable_ms,
> + .break_ctl = tegra_uart_break_ctl,
> + .startup = tegra_uart_startup,
> + .shutdown = tegra_uart_shutdown,
> + .set_termios = tegra_uart_set_termios,
> + .type = tegra_uart_type,
> + .request_port = tegra_uart_request_port,
> + .release_port = tegra_uart_release_port,
> +};
> +
> +static struct uart_driver tegra_uart_driver = {
> + .owner = THIS_MODULE,
> + .driver_name = "tegra_hsuart",
> + .dev_name = "ttyHS",
> + .cons = 0,
> + .nr = TEGRA_UART_MAXIMUM,
> +};
> +
> +static struct tegra_uart_platform_data *tegra_uart_parse_dt(
> + struct platform_device *pdev)
> +{
> + struct tegra_uart_platform_data *pdata;
> + struct device_node *np = pdev->dev.of_node;
> + u32 of_dma[2];
> +
> + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> + if (!pdata) {
> + dev_err(&pdev->dev, "Memory alloc for pdata failed\n");
> + return NULL;
> + }
> +
> + if (of_property_read_u32_array(np, "nvidia,dma-request-selector",
> + of_dma, 2) >= 0) {
> + pdata->dma_req_sel = of_dma[1];
> + } else {
> + dev_err(&pdev->dev, "missing dma requestor in device tree\n");
> + return NULL;
> + }
> +
> + if (!of_property_read_u32(np, "port-number", &of_dma[0])) {
> + pdata->port_number = of_dma[0];
> + } else {
> + dev_err(&pdev->dev, "missing port-number in device tree\n");
> + return NULL;
> + }
> +
> + if (of_get_property(np, "nvidia,enable-modem-interrupt", NULL))
> + pdata->enable_modem_interrupt = 1;
> +
> + return pdata;
> +}
> +
> +static struct of_device_id tegra_uart_of_match[] __devinitconst = {
> + {
> + .compatible = "nvidia,tegra30-hsuart",
> + .data = &tegra30_uart_chip_data,
> + }, {
> + .compatible = "nvidia,tegra20-hsuart",
> + .data = &tegra20_uart_chip_data,
> + }, {
> + },
> +};
> +MODULE_DEVICE_TABLE(of, tegra_uart_of_match);
> +
> +static int __devinit tegra_uart_probe(struct platform_device *pdev)
> +{
> + struct tegra_uart_port *tup;
> + struct uart_port *u;
> + struct tegra_uart_platform_data *pdata = pdev->dev.platform_data;
> + struct resource *resource;
> + int ret;
> + const struct tegra_uart_chip_data *cdata = &tegra30_uart_chip_data;
> + const struct of_device_id *match;
> +
> + if (pdev->dev.of_node) {
> + match = of_match_device(of_match_ptr(tegra_uart_of_match),
> + &pdev->dev);
> + if (!match) {
> + dev_err(&pdev->dev, "Error: No device match found\n");
> + return -ENODEV;
> + }
> + cdata = match->data;
> + }
> +
> + if (!pdata && pdev->dev.of_node)
> + pdata = tegra_uart_parse_dt(pdev);
> +
> + if (!pdata) {
> + dev_err(&pdev->dev, "No platform data, exiting\n");
> + return -ENODEV;
> + }
> +
> + tup = devm_kzalloc(&pdev->dev, sizeof(*tup), GFP_KERNEL);
> + if (!tup) {
> + dev_err(&pdev->dev, "Failed to allocate memory for tup\n");
> + return -ENOMEM;
> + }
> +
> + u = &tup->uport;
> + u->dev = &pdev->dev;
> + u->line = pdata->port_number;
> + u->ops = &tegra_uart_ops;
> + u->type = PORT_TEGRA;
> + u->fifosize = 32;
> + tup->dma_req_sel = pdata->dma_req_sel;
> + tup->cdata = cdata;
> + tup->enable_modem_interrupt = pdata->enable_modem_interrupt;
> +
> + platform_set_drvdata(pdev, tup);
> + resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!resource) {
> + dev_err(&pdev->dev, "No IO memory resource\n");
> + return -ENODEV;
> + }
> +
> + u->mapbase = resource->start;
> + u->membase = devm_request_and_ioremap(&pdev->dev, resource);
> + if (!u->membase) {
> + dev_err(&pdev->dev, "memregion/iomap address req failed\n");
> + return -EADDRNOTAVAIL;
> + }
> +
> + tup->uart_clk = devm_clk_get(&pdev->dev, "uart-clk");
> + if (IS_ERR(tup->uart_clk)) {
> + dev_err(&pdev->dev, "Couldn't get the clock\n");
> + return PTR_ERR(tup->uart_clk);
> + }
> +
> + u->iotype = UPIO_MEM32;
> + u->irq = platform_get_irq(pdev, 0);
> + u->regshift = 2;
> + ret = uart_add_one_port(&tegra_uart_driver, u);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "Failed to add uart port, err %d\n", ret);
> + return ret;
> + }
> + return ret;
> +}
> +
> +static int __devexit tegra_uart_remove(struct platform_device *pdev)
> +{
> + struct tegra_uart_port *tup = platform_get_drvdata(pdev);
> + struct uart_port *u = &tup->uport;
> +
> + uart_remove_one_port(&tegra_uart_driver, u);
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int tegra_uart_suspend(struct device *dev)
> +{
> + struct tegra_uart_port *tup = dev_get_drvdata(dev);
> + struct uart_port *u = &tup->uport;
> +
> + return uart_suspend_port(&tegra_uart_driver, u);
> +}
> +
> +static int tegra_uart_resume(struct device *dev)
> +{
> + struct tegra_uart_port *tup = dev_get_drvdata(dev);
> + struct uart_port *u = &tup->uport;
> +
> + return uart_resume_port(&tegra_uart_driver, u);
> +}
> +#endif
> +
> +static const struct dev_pm_ops tegra_uart_pm_ops = {
> + SET_SYSTEM_SLEEP_PM_OPS(tegra_uart_suspend, tegra_uart_resume)
> +};
> +
> +static struct platform_driver tegra_uart_platform_driver = {
> + .probe = tegra_uart_probe,
> + .remove = __devexit_p(tegra_uart_remove),
> + .driver = {
> + .name = "serial-tegra",
> + .of_match_table = of_match_ptr(tegra_uart_of_match),
> + .pm = &tegra_uart_pm_ops,
> + },
> +};
> +
> +static int __init tegra_uart_init(void)
> +{
> + int ret;
> +
> + ret = uart_register_driver(&tegra_uart_driver);
> + if (ret < 0) {
> + pr_err("Could not register %s driver\n",
> + tegra_uart_driver.driver_name);
> + return ret;
> + }
> +
> + ret = platform_driver_register(&tegra_uart_platform_driver);
> + if (ret < 0) {
> + pr_err("Uart platfrom driver register failed, e = %d\n", ret);
> + uart_unregister_driver(&tegra_uart_driver);
> + return ret;
> + }
> + return 0;
> +}
> +
> +static void __exit tegra_uart_exit(void)
> +{
> + pr_info("Unloading tegra uart driver\n");
> + platform_driver_unregister(&tegra_uart_platform_driver);
> + uart_unregister_driver(&tegra_uart_driver);
> +}
> +
> +module_init(tegra_uart_init);
> +module_exit(tegra_uart_exit);
> +
> +MODULE_ALIAS("platform:serial-tegra");
> +MODULE_DESCRIPTION("High speed UART driver for tegra chipset");
> +MODULE_AUTHOR("Laxman Dewangan <ldewangan@...dia.com>");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/serial_tegra.h b/include/linux/serial_tegra.h
> new file mode 100644
> index 0000000..f9828b8
> --- /dev/null
> +++ b/include/linux/serial_tegra.h
> @@ -0,0 +1,33 @@
> +/*
> + * serial_tegra.h
> + *
> + * Interface for High-speed serial driver for NVIDIA Tegra SoCs.
> + *
> + * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
> + *
> + * Author: Laxman Dewangan <ldewangan@...dia.com>
> + *
> + * 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/>.
> + */
> +
> +#ifndef _SERIAL_TEGRA_H_
> +#define _SERIAL_TEGRA_H_
> +
> +struct tegra_uart_platform_data {
> + int dma_req_sel;
> + int port_number;
> + unsigned enable_modem_interrupt:1;
> +};
> +
> +#endif /* _SERIAL_TEGRA_H_ */
> +
>
--
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