diff options
author | Lanqing Liu <lanqing.liu@unisoc.com> | 2019-03-04 16:58:24 +0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-03-28 00:30:01 +0900 |
commit | f4487db58eb780a52d768f3b36aaaa8fd5839215 (patch) | |
tree | 6a42e27a61856090865fb55577af8269ac118eae /drivers | |
parent | 083206100d971b457dc6a942748bdb3ccc72c947 (diff) |
serial: sprd: Add DMA mode support
Add DMA mode support for the Spreadtrum serial controller.
Signed-off-by: Lanqing Liu <lanqing.liu@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/tty/serial/sprd_serial.c | 440 |
1 files changed, 426 insertions, 14 deletions
diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c index 8f45b6671c19..6aebd77cd3c0 100644 --- a/drivers/tty/serial/sprd_serial.c +++ b/drivers/tty/serial/sprd_serial.c @@ -10,6 +10,9 @@ #include <linux/clk.h> #include <linux/console.h> #include <linux/delay.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/dma/sprd-dma.h> #include <linux/io.h> #include <linux/ioport.h> #include <linux/kernel.h> @@ -75,6 +78,7 @@ /* control register 1 */ #define SPRD_CTL1 0x001C +#define SPRD_DMA_EN BIT(15) #define RX_HW_FLOW_CTL_THLD BIT(6) #define RX_HW_FLOW_CTL_EN BIT(7) #define TX_HW_FLOW_CTL_EN BIT(8) @@ -86,6 +90,7 @@ #define THLD_TX_EMPTY 0x40 #define THLD_TX_EMPTY_SHIFT 8 #define THLD_RX_FULL 0x40 +#define THLD_RX_FULL_MASK GENMASK(6, 0) /* config baud rate register */ #define SPRD_CLKD0 0x0024 @@ -102,15 +107,36 @@ #define SPRD_IMSR_TIMEOUT BIT(13) #define SPRD_DEFAULT_SOURCE_CLK 26000000 +#define SPRD_RX_DMA_STEP 1 +#define SPRD_RX_FIFO_FULL 1 +#define SPRD_TX_FIFO_FULL 0x20 +#define SPRD_UART_RX_SIZE (UART_XMIT_SIZE / 4) + +struct sprd_uart_dma { + struct dma_chan *chn; + unsigned char *virt; + dma_addr_t phys_addr; + dma_cookie_t cookie; + u32 trans_len; + bool enable; +}; + struct sprd_uart_port { struct uart_port port; char name[16]; struct clk *clk; + struct sprd_uart_dma tx_dma; + struct sprd_uart_dma rx_dma; + dma_addr_t pos; + unsigned char *rx_buf_tail; }; static struct sprd_uart_port *sprd_port[UART_NR_MAX]; static int sprd_ports_num; +static int sprd_start_dma_rx(struct uart_port *port); +static int sprd_tx_dma_config(struct uart_port *port); + static inline unsigned int serial_in(struct uart_port *port, unsigned int offset) { @@ -141,45 +167,389 @@ static void sprd_set_mctrl(struct uart_port *port, unsigned int mctrl) /* nothing to do */ } -static void sprd_stop_tx(struct uart_port *port) +static void sprd_stop_rx(struct uart_port *port) { + struct sprd_uart_port *sp = + container_of(port, struct sprd_uart_port, port); unsigned int ien, iclr; + if (sp->rx_dma.enable) + dmaengine_terminate_all(sp->rx_dma.chn); + iclr = serial_in(port, SPRD_ICLR); ien = serial_in(port, SPRD_IEN); - iclr |= SPRD_IEN_TX_EMPTY; - ien &= ~SPRD_IEN_TX_EMPTY; + ien &= ~(SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT); + iclr |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT; - serial_out(port, SPRD_ICLR, iclr); serial_out(port, SPRD_IEN, ien); + serial_out(port, SPRD_ICLR, iclr); } -static void sprd_start_tx(struct uart_port *port) +static void sprd_uart_dma_enable(struct uart_port *port, bool enable) { - unsigned int ien; + u32 val = serial_in(port, SPRD_CTL1); - ien = serial_in(port, SPRD_IEN); - if (!(ien & SPRD_IEN_TX_EMPTY)) { - ien |= SPRD_IEN_TX_EMPTY; - serial_out(port, SPRD_IEN, ien); + if (enable) + val |= SPRD_DMA_EN; + else + val &= ~SPRD_DMA_EN; + + serial_out(port, SPRD_CTL1, val); +} + +static void sprd_stop_tx_dma(struct uart_port *port) +{ + struct sprd_uart_port *sp = + container_of(port, struct sprd_uart_port, port); + struct circ_buf *xmit = &port->state->xmit; + struct dma_tx_state state; + u32 trans_len; + + dmaengine_pause(sp->tx_dma.chn); + + dmaengine_tx_status(sp->tx_dma.chn, sp->tx_dma.cookie, &state); + if (state.residue) { + trans_len = state.residue - sp->tx_dma.phys_addr; + xmit->tail = (xmit->tail + trans_len) & (UART_XMIT_SIZE - 1); + port->icount.tx += trans_len; + dma_unmap_single(port->dev, sp->tx_dma.phys_addr, + sp->tx_dma.trans_len, DMA_TO_DEVICE); } + + dmaengine_terminate_all(sp->tx_dma.chn); + sp->tx_dma.trans_len = 0; } -static void sprd_stop_rx(struct uart_port *port) +static int sprd_tx_buf_remap(struct uart_port *port) +{ + struct sprd_uart_port *sp = + container_of(port, struct sprd_uart_port, port); + struct circ_buf *xmit = &port->state->xmit; + + sp->tx_dma.trans_len = + CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); + + sp->tx_dma.phys_addr = dma_map_single(port->dev, + (void *)&(xmit->buf[xmit->tail]), + sp->tx_dma.trans_len, + DMA_TO_DEVICE); + return dma_mapping_error(port->dev, sp->tx_dma.phys_addr); +} + +static void sprd_complete_tx_dma(void *data) +{ + struct uart_port *port = (struct uart_port *)data; + struct sprd_uart_port *sp = + container_of(port, struct sprd_uart_port, port); + struct circ_buf *xmit = &port->state->xmit; + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + dma_unmap_single(port->dev, sp->tx_dma.phys_addr, + sp->tx_dma.trans_len, DMA_TO_DEVICE); + + xmit->tail = (xmit->tail + sp->tx_dma.trans_len) & (UART_XMIT_SIZE - 1); + port->icount.tx += sp->tx_dma.trans_len; + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(port); + + if (uart_circ_empty(xmit) || sprd_tx_buf_remap(port) || + sprd_tx_dma_config(port)) + sp->tx_dma.trans_len = 0; + + spin_unlock_irqrestore(&port->lock, flags); +} + +static int sprd_uart_dma_submit(struct uart_port *port, + struct sprd_uart_dma *ud, u32 trans_len, + enum dma_transfer_direction direction, + dma_async_tx_callback callback) { + struct dma_async_tx_descriptor *dma_des; + unsigned long flags; + + flags = SPRD_DMA_FLAGS(SPRD_DMA_CHN_MODE_NONE, + SPRD_DMA_NO_TRG, + SPRD_DMA_FRAG_REQ, + SPRD_DMA_TRANS_INT); + + dma_des = dmaengine_prep_slave_single(ud->chn, ud->phys_addr, trans_len, + direction, flags); + if (!dma_des) + return -ENODEV; + + dma_des->callback = callback; + dma_des->callback_param = port; + + ud->cookie = dmaengine_submit(dma_des); + if (dma_submit_error(ud->cookie)) + return dma_submit_error(ud->cookie); + + dma_async_issue_pending(ud->chn); + + return 0; +} + +static int sprd_tx_dma_config(struct uart_port *port) +{ + struct sprd_uart_port *sp = + container_of(port, struct sprd_uart_port, port); + u32 burst = sp->tx_dma.trans_len > SPRD_TX_FIFO_FULL ? + SPRD_TX_FIFO_FULL : sp->tx_dma.trans_len; + int ret; + struct dma_slave_config cfg = { + .dst_addr = port->mapbase + SPRD_TXD, + .src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE, + .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE, + .src_maxburst = burst, + }; + + ret = dmaengine_slave_config(sp->tx_dma.chn, &cfg); + if (ret < 0) + return ret; + + return sprd_uart_dma_submit(port, &sp->tx_dma, sp->tx_dma.trans_len, + DMA_MEM_TO_DEV, sprd_complete_tx_dma); +} + +static void sprd_start_tx_dma(struct uart_port *port) +{ + struct sprd_uart_port *sp = + container_of(port, struct sprd_uart_port, port); + struct circ_buf *xmit = &port->state->xmit; + + if (port->x_char) { + serial_out(port, SPRD_TXD, port->x_char); + port->icount.tx++; + port->x_char = 0; + return; + } + + if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { + sprd_stop_tx_dma(port); + return; + } + + if (sp->tx_dma.trans_len) + return; + + if (sprd_tx_buf_remap(port) || sprd_tx_dma_config(port)) + sp->tx_dma.trans_len = 0; +} + +static void sprd_rx_full_thld(struct uart_port *port, u32 thld) +{ + u32 val = serial_in(port, SPRD_CTL2); + + val &= ~THLD_RX_FULL_MASK; + val |= thld & THLD_RX_FULL_MASK; + serial_out(port, SPRD_CTL2, val); +} + +static int sprd_rx_alloc_buf(struct sprd_uart_port *sp) +{ + sp->rx_dma.virt = dma_alloc_coherent(sp->port.dev, SPRD_UART_RX_SIZE, + &sp->rx_dma.phys_addr, GFP_KERNEL); + if (!sp->rx_dma.virt) + return -ENOMEM; + + return 0; +} + +static void sprd_rx_free_buf(struct sprd_uart_port *sp) +{ + if (sp->rx_dma.virt) + dma_free_coherent(sp->port.dev, SPRD_UART_RX_SIZE, + sp->rx_dma.virt, sp->rx_dma.phys_addr); + +} + +static int sprd_rx_dma_config(struct uart_port *port, u32 burst) +{ + struct sprd_uart_port *sp = + container_of(port, struct sprd_uart_port, port); + struct dma_slave_config cfg = { + .src_addr = port->mapbase + SPRD_RXD, + .src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE, + .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE, + .src_maxburst = burst, + }; + + return dmaengine_slave_config(sp->rx_dma.chn, &cfg); +} + +static void sprd_uart_dma_rx(struct uart_port *port) +{ + struct sprd_uart_port *sp = + container_of(port, struct sprd_uart_port, port); + struct tty_port *tty = &port->state->port; + + port->icount.rx += sp->rx_dma.trans_len; + tty_insert_flip_string(tty, sp->rx_buf_tail, sp->rx_dma.trans_len); + tty_flip_buffer_push(tty); +} + +static void sprd_uart_dma_irq(struct uart_port *port) +{ + struct sprd_uart_port *sp = + container_of(port, struct sprd_uart_port, port); + struct dma_tx_state state; + enum dma_status status; + + status = dmaengine_tx_status(sp->rx_dma.chn, + sp->rx_dma.cookie, &state); + if (status == DMA_ERROR) + sprd_stop_rx(port); + + if (!state.residue && sp->pos == sp->rx_dma.phys_addr) + return; + + if (!state.residue) { + sp->rx_dma.trans_len = SPRD_UART_RX_SIZE + + sp->rx_dma.phys_addr - sp->pos; + sp->pos = sp->rx_dma.phys_addr; + } else { + sp->rx_dma.trans_len = state.residue - sp->pos; + sp->pos = state.residue; + } + + sprd_uart_dma_rx(port); + sp->rx_buf_tail += sp->rx_dma.trans_len; +} + +static void sprd_complete_rx_dma(void *data) +{ + struct uart_port *port = (struct uart_port *)data; + struct sprd_uart_port *sp = + container_of(port, struct sprd_uart_port, port); + struct dma_tx_state state; + enum dma_status status; + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + + status = dmaengine_tx_status(sp->rx_dma.chn, + sp->rx_dma.cookie, &state); + if (status != DMA_COMPLETE) { + sprd_stop_rx(port); + spin_unlock_irqrestore(&port->lock, flags); + return; + } + + if (sp->pos != sp->rx_dma.phys_addr) { + sp->rx_dma.trans_len = SPRD_UART_RX_SIZE + + sp->rx_dma.phys_addr - sp->pos; + sprd_uart_dma_rx(port); + sp->rx_buf_tail += sp->rx_dma.trans_len; + } + + if (sprd_start_dma_rx(port)) + sprd_stop_rx(port); + + spin_unlock_irqrestore(&port->lock, flags); +} + +static int sprd_start_dma_rx(struct uart_port *port) +{ + struct sprd_uart_port *sp = + container_of(port, struct sprd_uart_port, port); + int ret; + + if (!sp->rx_dma.enable) + return 0; + + sp->pos = sp->rx_dma.phys_addr; + sp->rx_buf_tail = sp->rx_dma.virt; + sprd_rx_full_thld(port, SPRD_RX_FIFO_FULL); + ret = sprd_rx_dma_config(port, SPRD_RX_DMA_STEP); + if (ret) + return ret; + + return sprd_uart_dma_submit(port, &sp->rx_dma, SPRD_UART_RX_SIZE, + DMA_DEV_TO_MEM, sprd_complete_rx_dma); +} + +static void sprd_release_dma(struct uart_port *port) +{ + struct sprd_uart_port *sp = + container_of(port, struct sprd_uart_port, port); + + sprd_uart_dma_enable(port, false); + + if (sp->rx_dma.enable) + dma_release_channel(sp->rx_dma.chn); + + if (sp->tx_dma.enable) + dma_release_channel(sp->tx_dma.chn); + + sp->tx_dma.enable = false; + sp->rx_dma.enable = false; +} + +static void sprd_request_dma(struct uart_port *port) +{ + struct sprd_uart_port *sp = + container_of(port, struct sprd_uart_port, port); + + sp->tx_dma.enable = true; + sp->rx_dma.enable = true; + + sp->tx_dma.chn = dma_request_chan(port->dev, "tx"); + if (IS_ERR(sp->tx_dma.chn)) { + dev_err(port->dev, "request TX DMA channel failed, ret = %ld\n", + PTR_ERR(sp->tx_dma.chn)); + sp->tx_dma.enable = false; + } + + sp->rx_dma.chn = dma_request_chan(port->dev, "rx"); + if (IS_ERR(sp->rx_dma.chn)) { + dev_err(port->dev, "request RX DMA channel failed, ret = %ld\n", + PTR_ERR(sp->tx_dma.chn)); + sp->rx_dma.enable = false; + } +} + +static void sprd_stop_tx(struct uart_port *port) +{ + struct sprd_uart_port *sp = container_of(port, struct sprd_uart_port, + port); unsigned int ien, iclr; + if (sp->tx_dma.enable) { + sprd_stop_tx_dma(port); + return; + } + iclr = serial_in(port, SPRD_ICLR); ien = serial_in(port, SPRD_IEN); - ien &= ~(SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT); - iclr |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT; + iclr |= SPRD_IEN_TX_EMPTY; + ien &= ~SPRD_IEN_TX_EMPTY; serial_out(port, SPRD_IEN, ien); serial_out(port, SPRD_ICLR, iclr); } +static void sprd_start_tx(struct uart_port *port) +{ + struct sprd_uart_port *sp = container_of(port, struct sprd_uart_port, + port); + unsigned int ien; + + if (sp->tx_dma.enable) { + sprd_start_tx_dma(port); + return; + } + + ien = serial_in(port, SPRD_IEN); + if (!(ien & SPRD_IEN_TX_EMPTY)) { + ien |= SPRD_IEN_TX_EMPTY; + serial_out(port, SPRD_IEN, ien); + } +} + /* The Sprd serial does not support this function. */ static void sprd_break_ctl(struct uart_port *port, int break_state) { @@ -220,9 +590,16 @@ static int handle_lsr_errors(struct uart_port *port, static inline void sprd_rx(struct uart_port *port) { + struct sprd_uart_port *sp = container_of(port, struct sprd_uart_port, + port); struct tty_port *tty = &port->state->port; unsigned int ch, flag, lsr, max_count = SPRD_TIMEOUT; + if (sp->rx_dma.enable) { + sprd_uart_dma_irq(port); + return; + } + while ((serial_in(port, SPRD_STS1) & SPRD_RX_FIFO_CNT_MASK) && max_count--) { lsr = serial_in(port, SPRD_LSR); @@ -306,6 +683,25 @@ static irqreturn_t sprd_handle_irq(int irq, void *dev_id) return IRQ_HANDLED; } +static void sprd_uart_dma_startup(struct uart_port *port, + struct sprd_uart_port *sp) +{ + int ret; + + sprd_request_dma(port); + if (!(sp->rx_dma.enable || sp->tx_dma.enable)) + return; + + ret = sprd_start_dma_rx(port); + if (ret) { + sp->rx_dma.enable = false; + dma_release_channel(sp->rx_dma.chn); + dev_warn(port->dev, "fail to start RX dma mode\n"); + } + + sprd_uart_dma_enable(port, true); +} + static int sprd_startup(struct uart_port *port) { int ret = 0; @@ -334,6 +730,9 @@ static int sprd_startup(struct uart_port *port) /* allocate irq */ sp = container_of(port, struct sprd_uart_port, port); snprintf(sp->name, sizeof(sp->name), "sprd_serial%d", port->line); + + sprd_uart_dma_startup(port, sp); + ret = devm_request_irq(port->dev, port->irq, sprd_handle_irq, IRQF_SHARED, sp->name, port); if (ret) { @@ -348,7 +747,9 @@ static int sprd_startup(struct uart_port *port) /* enable interrupt */ spin_lock_irqsave(&port->lock, flags); ien = serial_in(port, SPRD_IEN); - ien |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT | SPRD_IEN_TIMEOUT; + ien |= SPRD_IEN_BREAK_DETECT | SPRD_IEN_TIMEOUT; + if (!sp->rx_dma.enable) + ien |= SPRD_IEN_RX_FULL; serial_out(port, SPRD_IEN, ien); spin_unlock_irqrestore(&port->lock, flags); @@ -357,6 +758,7 @@ static int sprd_startup(struct uart_port *port) static void sprd_shutdown(struct uart_port *port) { + sprd_release_dma(port); serial_out(port, SPRD_IEN, 0); serial_out(port, SPRD_ICLR, ~0); devm_free_irq(port->dev, port->irq, port); @@ -687,6 +1089,8 @@ static int sprd_remove(struct platform_device *dev) if (!sprd_ports_num) uart_unregister_driver(&sprd_uart_driver); + sprd_rx_free_buf(sup); + return 0; } @@ -775,6 +1179,14 @@ static int sprd_probe(struct platform_device *pdev) } up->irq = irq; + /* + * Allocate one dma buffer to prepare for receive transfer, in case + * memory allocation failure at runtime. + */ + ret = sprd_rx_alloc_buf(sprd_port[index]); + if (ret) + return ret; + if (!sprd_ports_num) { ret = uart_register_driver(&sprd_uart_driver); if (ret < 0) { |