diff options
| -rwxr-xr-x | drivers/serial/tegra_hsuart.c | 150 |
1 files changed, 106 insertions, 44 deletions
diff --git a/drivers/serial/tegra_hsuart.c b/drivers/serial/tegra_hsuart.c index 613d2543e9a0..7c1b1ac5bf42 100755 --- a/drivers/serial/tegra_hsuart.c +++ b/drivers/serial/tegra_hsuart.c @@ -27,6 +27,7 @@ #include <linux/serial.h> #include <linux/serial_core.h> #include <linux/platform_device.h> +#include <linux/workqueue.h> #include <linux/io.h> #include <linux/dma-mapping.h> #include <linux/dmapool.h> @@ -49,7 +50,7 @@ #define BYTES_TO_ALIGN(x) ((unsigned long)(ALIGN((x), sizeof(u32))) - \ (unsigned long)(x)) -#define UART_RX_DMA_BUFFER_SIZE 2048 +#define UART_RX_DMA_BUFFER_SIZE (2048*4) #define UART_LSR_FIFOE 0x80 #define UART_IER_EORD 0x20 @@ -87,6 +88,9 @@ const int dma_req_sel[] = { #define TEGRA_UART_TX_TRIG_4B 0x20 #define TEGRA_UART_TX_TRIG_1B 0x30 +/* Wait time in microsec to complete current burst and update status */ +#define WAITTIME_DMA_BURST_COMPLETE 20 + struct tegra_uart_port { struct uart_port uport; char port_name[32]; @@ -126,6 +130,9 @@ struct tegra_uart_port { bool rx_timeout; int uart_state; NvOdmUartHandle odm_uart_handle; + int rx_in_progress; + struct work_struct rx_work; + struct workqueue_struct *rx_work_queue; }; static inline u8 uart_readb(struct tegra_uart_port *t, unsigned long reg) @@ -256,6 +263,7 @@ static void tegra_start_tx(struct uart_port *u) static int tegra_start_dma_rx(struct tegra_uart_port *t) { wmb(); + t->rx_dma_req.bytes_transferred = 0; if (tegra_dma_enqueue_req(t->rx_dma, &t->rx_dma_req)) { dev_err(t->uport.dev, "Could not enqueue Rx DMA req\n"); return -EINVAL; @@ -266,22 +274,7 @@ static int tegra_start_dma_rx(struct tegra_uart_port *t) static void tegra_rx_dma_threshold_callback(struct tegra_dma_req *req) { struct tegra_uart_port *t = req->dev; - struct uart_port *u = &t->uport; - unsigned long flags; - - spin_lock_irqsave(&u->lock, flags); - - if (t->rts_active) - set_rts(t, false); - tegra_dma_dequeue(t->rx_dma); - - /* enqueue the request again */ - tegra_start_dma_rx(t); - - if (t->rts_active) - set_rts(t, true); - - spin_unlock_irqrestore(&u->lock, flags); + queue_work(t->rx_work_queue, &t->rx_work); } /* It is expected that the callers take the UART lock when this API is called. @@ -312,10 +305,11 @@ static void tegra_rx_dma_complete_callback(struct tegra_dma_req *req) req->bytes_transferred); } - if (t->rx_timeout) { - t->rx_timeout = 0; - do_handle_rx_pio(t); - } + do_handle_rx_pio(t); + + /* Push the read data later in caller place. */ + if (req->status == -TEGRA_DMA_REQ_ERROR_ABORTED) + return; spin_unlock(&u->lock); tty_flip_buffer_push(u->state->port.tty); @@ -325,9 +319,12 @@ static void tegra_rx_dma_complete_callback(struct tegra_dma_req *req) /* Lock already taken */ static void do_handle_rx_dma(struct tegra_uart_port *t) { + struct uart_port *u = &t->uport; if (t->rts_active) set_rts(t, false); + udelay(WAITTIME_DMA_BURST_COMPLETE); tegra_dma_dequeue(t->rx_dma); + tty_flip_buffer_push(u->state->port.tty); /* enqueue the request again */ tegra_start_dma_rx(t); if (t->rts_active) @@ -393,6 +390,33 @@ static void do_handle_rx_pio(struct tegra_uart_port *t) return; } +static void tegra_rx_dma_workqueue(struct work_struct *w) +{ + struct tegra_uart_port *t; + struct uart_port *u; + unsigned long flags; + unsigned char ier; + + t = container_of(w, struct tegra_uart_port, rx_work); + u = &t->uport; + + if (!t->rx_in_progress) { + dev_dbg(t->uport.dev, "The Rx is stopped\n"); + return; + } + + do_handle_rx_dma(t); + + spin_lock_irqsave(&u->lock, flags); + if (t->rx_in_progress) { + ier = t->ier_shadow; + ier |= (UART_IER_RLSI | UART_IER_RTOIE | UART_IER_EORD); + t->ier_shadow = ier; + uart_writeb(t, ier, UART_IER); + } + spin_unlock_irqrestore(&u->lock, flags); + return; +} static void do_handle_modem_signal(struct uart_port *u) { @@ -455,6 +479,7 @@ static irqreturn_t tegra_uart_isr(int irq, void *data) struct uart_port *u = &t->uport; unsigned char iir; unsigned char ier; + bool is_rx_int = false; unsigned long flags; spin_lock_irqsave(&u->lock, flags); @@ -462,6 +487,11 @@ static irqreturn_t tegra_uart_isr(int irq, void *data) while (1) { iir = uart_readb(t, UART_IIR); if (iir & UART_IIR_NO_INT) { + if (likely(t->use_rx_dma)) { + if (is_rx_int) { + queue_work(t->rx_work_queue, &t->rx_work); + } + } spin_unlock_irqrestore(&u->lock, flags); return IRQ_HANDLED; } @@ -478,27 +508,25 @@ static irqreturn_t tegra_uart_isr(int irq, void *data) do_handle_tx_pio(t); break; case 4: /* End of data */ - /* As per hw spec, to clear EORD interrupt, we need - * to disable and then re-enable the interrupt. - */ - ier = t->ier_shadow; - ier &= ~UART_IER_EORD; - uart_writeb(t, ier, UART_IER); - ier |= UART_IER_EORD; - uart_writeb(t, ier, UART_IER); - /* fallthrough */ case 6: /* Rx timeout */ - t->rx_timeout = 1; - /* fallthrough */ case 2: /* Receive */ - if (likely(t->use_rx_dma)) - do_handle_rx_dma(t); - else - do_handle_rx_pio(t); - - spin_unlock_irqrestore(&u->lock, flags); - tty_flip_buffer_push(u->state->port.tty); - spin_lock_irqsave(&u->lock, flags); + if (likely(t->use_rx_dma)) { + if (!is_rx_int) { + is_rx_int = true; + /* Disable interrups */ + ier = t->ier_shadow; + ier |= UART_IER_RDI; + uart_writeb(t, ier, UART_IER); + ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE | UART_IER_EORD); + t->ier_shadow = ier; + uart_writeb(t, ier, UART_IER); + } + } else { + do_handle_rx_pio(t); + spin_unlock_irqrestore(&u->lock, flags); + tty_flip_buffer_push(u->state->port.tty); + spin_lock_irqsave(&u->lock, flags); + } break; case 3: /* Receive error */ /* FIXME how to handle this? Why do we get here */ @@ -514,13 +542,29 @@ static irqreturn_t tegra_uart_isr(int irq, void *data) static void tegra_stop_rx(struct uart_port *u) { struct tegra_uart_port *t; + unsigned char ier; t = container_of(u, struct tegra_uart_port, uport); if (t->rts_active) set_rts(t, false); - if (t->rx_dma) + + if (t->rx_in_progress) { + /* Enable the interrupts */ + ier = t->ier_shadow; + ier |= UART_IER_RDI; + uart_writeb(t, ier, UART_IER); + + ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE | UART_IER_EORD); + t->ier_shadow = ier; + uart_writeb(t, ier, UART_IER); + t->rx_in_progress = 0; + } + + if (t->rx_dma) { tegra_dma_dequeue(t->rx_dma); + tty_flip_buffer_push(u->state->port.tty); + } return; } @@ -582,6 +626,8 @@ static int tegra_uart_hw_init(struct tegra_uart_port *t) clk_enable(t->clk); msleep(10); + t->rx_in_progress = 0; + /* Reset the FIFO twice with some delay to make sure that the FIFOs are * really flushed. Wait is needed as the clearing needs to cross * multiple clock domains. @@ -638,6 +684,8 @@ static int tegra_uart_hw_init(struct tegra_uart_port *t) else uart_writeb(t, t->fcr_shadow, UART_FCR); + t->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. @@ -745,7 +793,7 @@ static int tegra_startup(struct uart_port *u) t->tx_in_progress = 0; t->use_rx_dma = false; - if (!TX_FORCE_PIO) { + if (!RX_FORCE_PIO) { if (!tegra_uart_init_rx_dma(t)) t->use_rx_dma = true; } @@ -1192,6 +1240,7 @@ static int __devexit tegra_uart_remove(struct platform_device *pdev) uart_remove_one_port(&tegra_uart_driver, u); if (t->odm_uart_handle) NvOdmUartClose(t->odm_uart_handle); + destroy_workqueue(t->rx_work_queue); platform_set_drvdata(pdev, NULL); @@ -1248,16 +1297,31 @@ static int __init tegra_uart_probe(struct platform_device *pdev) return ret; } + /* Create the workqueue for the Rx Path */ + snprintf(name, sizeof(name), "tegra_hsuart_rx_%d", u->line); + t->rx_work_queue = create_singlethread_workqueue(name); + if (t->rx_work_queue == NULL) { + dev_err(u->dev, "Failed to create work queue\n"); + ret = -ENODEV; + goto rx_workq_fail; + } + INIT_WORK(&t->rx_work, tegra_rx_dma_workqueue); + snprintf(name, sizeof(name), "tegra_hsuart_%d", u->line); pr_info("Registered UART port %s%d\n", tegra_uart_driver.dev_name, u->line); t->uart_state = TEGRA_UART_CLOSED; return ret; + +rx_workq_fail: + uart_remove_one_port(&tegra_uart_driver, u); + fail: if (t->odm_uart_handle) NvOdmUartClose(t->odm_uart_handle); kfree(t); + platform_set_drvdata(pdev, NULL); return -ENODEV; } @@ -1299,12 +1363,10 @@ void tegra_uart_request_clock_on(struct uart_port *uport) void tegra_uart_set_mctrl(struct uart_port *uport, unsigned int mctrl) { unsigned long flags; - unsigned char mcr; struct tegra_uart_port *t; t = container_of(uport, struct tegra_uart_port, uport); spin_lock_irqsave(&uport->lock, flags); - mcr = t->mcr_shadow; if (mctrl & TIOCM_RTS) { t->rts_active = true; set_rts(t, true); |