diff options
Diffstat (limited to 'kernel/drivers/tty/serial/serial-tegra.c')
| -rw-r--r-- | kernel/drivers/tty/serial/serial-tegra.c | 1408 |
1 files changed, 1408 insertions, 0 deletions
diff --git a/kernel/drivers/tty/serial/serial-tegra.c b/kernel/drivers/tty/serial/serial-tegra.c new file mode 100644 index 000000000..1d5ea3964 --- /dev/null +++ b/kernel/drivers/tty/serial/serial-tegra.c @@ -0,0 +1,1408 @@ +/* + * serial_tegra.c + * + * High-speed serial driver for NVIDIA Tegra SoCs + * + * Copyright (c) 2012-2013, NVIDIA CORPORATION. All rights reserved. + * + * Author: Laxman Dewangan <ldewangan@nvidia.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/err.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/reset.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/termios.h> +#include <linux/tty.h> +#include <linux/tty_flip.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_port { + struct uart_port uport; + const struct tegra_uart_chip_data *cdata; + + struct clk *uart_clk; + struct reset_control *rst; + 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; + + bool enable_modem_interrupt; + + bool rx_timeout; + int rx_in_progress; + int symb_bit; + + 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; + int dtr_enable; + + mcr = tup->mcr_shadow; + tup->rts_active = !!(mctrl & TIOCM_RTS); + set_rts(tup, tup->rts_active); + + dtr_enable = !!(mctrl & TIOCM_DTR); + set_dtr(tup, dtr_enable); + 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; + + if (tup->tx_in_progress != TEGRA_UART_TX_DMA) + return; + + 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, + struct tty_port *tty) +{ + 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) && tty) + tty_insert_flip_char(tty, ch, flag); + } while (1); + + return; +} + +static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup, + struct tty_port *tty, int count) +{ + int copied; + + tup->uport.icount.rx += count; + if (!tty) { + dev_err(tup->uport.dev, "No tty port\n"); + return; + } + 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(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; + struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port); + struct tty_port *port = &u->state->port; + 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, port, count); + + tegra_uart_handle_rx_pio(tup, port); + if (tty) { + spin_unlock_irqrestore(&u->lock, flags); + tty_flip_buffer_push(port); + spin_lock_irqsave(&u->lock, flags); + tty_kref_put(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, + unsigned long *flags) +{ + struct dma_tx_state state; + struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port); + struct tty_port *port = &tup->uport.state->port; + struct uart_port *u = &tup->uport; + 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); + async_tx_ack(tup->rx_dma_desc); + count = tup->rx_bytes_requested - state.residue; + + /* If we are here, DMA is stopped */ + if (count) + tegra_uart_copy_rx_to_tty(tup, port, count); + + tegra_uart_handle_rx_pio(tup, port); + if (tty) { + spin_unlock_irqrestore(&u->lock, *flags); + tty_flip_buffer_push(port); + spin_lock_irqsave(&u->lock, *flags); + tty_kref_put(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, &flags); + 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 tty_struct *tty; + struct tty_port *port = &u->state->port; + struct dma_tx_state state; + unsigned long ier; + int count; + + if (tup->rts_active) + set_rts(tup, false); + + if (!tup->rx_in_progress) + return; + + tty = tty_port_tty_get(&tup->uport.state->port); + + 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, port, count); + tegra_uart_handle_rx_pio(tup, port); + } else { + tegra_uart_handle_rx_pio(tup, port); + } + if (tty) { + tty_flip_buffer_push(port); + tty_kref_put(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.*/ + reset_control_assert(tup->rst); + udelay(10); + reset_control_deassert(tup->rst); + + 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_chan = dma_request_slave_channel_reason(tup->uport.dev, + dma_to_memory ? "rx" : "tx"); + if (IS_ERR(dma_chan)) { + ret = PTR_ERR(dma_chan); + dev_err(tup->uport.dev, + "DMA channel alloc failed: %d\n", ret); + return ret; + } + + 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; + } + + 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, 0, + 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; +} + +/* + * 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 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); + + tegra_uart_flush_buffer(u); +} + +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; + int symb_bit = 1; + struct clk *parent_clk = clk_get_parent(tup->uart_clk); + unsigned long parent_clk_rate = clk_get_rate(parent_clk); + int max_divider = (tup->cdata->support_clk_src_div) ? 0x7FFF : 0xFFFF; + + max_divider *= 16; + 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; + + /* CMSPAR isn't supported by this driver */ + termios->c_cflag &= ~CMSPAR; + + if ((termios->c_cflag & PARENB) == PARENB) { + symb_bit++; + if (termios->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 (termios->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, + parent_clk_rate/max_divider, + parent_clk_rate/16); + spin_unlock_irqrestore(&u->lock, flags); + tegra_set_baudrate(tup, baud); + if (tty_termios_baud_rate(termios)) + tty_termios_encode_baud_rate(termios, baud, 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; +} + +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 = "ttyTHS", + .cons = NULL, + .nr = TEGRA_UART_MAXIMUM, +}; + +static int tegra_uart_parse_dt(struct platform_device *pdev, + struct tegra_uart_port *tup) +{ + struct device_node *np = pdev->dev.of_node; + int port; + + port = of_alias_get_id(np, "serial"); + if (port < 0) { + dev_err(&pdev->dev, "failed to get alias id, errno %d\n", port); + return port; + } + tup->uport.line = port; + + tup->enable_modem_interrupt = of_property_read_bool(np, + "nvidia,enable-modem-interrupt"); + return 0; +} + +static 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, +}; + +static 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, +}; + +static const struct of_device_id tegra_uart_of_match[] = { + { + .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 tegra_uart_probe(struct platform_device *pdev) +{ + struct tegra_uart_port *tup; + struct uart_port *u; + struct resource *resource; + int ret; + const struct tegra_uart_chip_data *cdata; + const struct of_device_id *match; + + match = of_match_device(tegra_uart_of_match, &pdev->dev); + if (!match) { + dev_err(&pdev->dev, "Error: No device match found\n"); + return -ENODEV; + } + cdata = match->data; + + tup = devm_kzalloc(&pdev->dev, sizeof(*tup), GFP_KERNEL); + if (!tup) { + dev_err(&pdev->dev, "Failed to allocate memory for tup\n"); + return -ENOMEM; + } + + ret = tegra_uart_parse_dt(pdev, tup); + if (ret < 0) + return ret; + + u = &tup->uport; + u->dev = &pdev->dev; + u->ops = &tegra_uart_ops; + u->type = PORT_TEGRA; + u->fifosize = 32; + tup->cdata = cdata; + + 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_ioremap_resource(&pdev->dev, resource); + if (IS_ERR(u->membase)) + return PTR_ERR(u->membase); + + tup->uart_clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(tup->uart_clk)) { + dev_err(&pdev->dev, "Couldn't get the clock\n"); + return PTR_ERR(tup->uart_clk); + } + + tup->rst = devm_reset_control_get(&pdev->dev, "serial"); + if (IS_ERR(tup->rst)) { + dev_err(&pdev->dev, "Couldn't get the reset\n"); + return PTR_ERR(tup->rst); + } + + 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 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 = tegra_uart_remove, + .driver = { + .name = "serial-tegra", + .of_match_table = 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 platform 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@nvidia.com>"); +MODULE_LICENSE("GPL v2"); |