diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/tty/serial/8250/8250.c | 31 | ||||
| -rw-r--r-- | drivers/tty/serial/8250/8250.h | 50 | ||||
| -rw-r--r-- | drivers/tty/serial/8250/8250_dma.c | 213 | ||||
| -rw-r--r-- | drivers/tty/serial/8250/Kconfig | 8 | ||||
| -rw-r--r-- | drivers/tty/serial/8250/Makefile | 1 |
5 files changed, 300 insertions, 3 deletions
diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c index e2ac25a037ef..cb7db5a8ae92 100644 --- a/drivers/tty/serial/8250/8250.c +++ b/drivers/tty/serial/8250/8250.c @@ -1269,7 +1269,9 @@ static void serial8250_start_tx(struct uart_port *port) struct uart_8250_port *up = container_of(port, struct uart_8250_port, port); - if (!(up->ier & UART_IER_THRI)) { + if (up->dma && !serial8250_tx_dma(up)) { + return; + } else if (!(up->ier & UART_IER_THRI)) { up->ier |= UART_IER_THRI; serial_port_out(port, UART_IER, up->ier); @@ -1467,6 +1469,7 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir) unsigned long flags; struct uart_8250_port *up = container_of(port, struct uart_8250_port, port); + int dma_err = 0; if (iir & UART_IIR_NO_INT) return 0; @@ -1477,8 +1480,13 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir) DEBUG_INTR("status = %x...", status); - if (status & (UART_LSR_DR | UART_LSR_BI)) - status = serial8250_rx_chars(up, status); + if (status & (UART_LSR_DR | UART_LSR_BI)) { + if (up->dma) + dma_err = serial8250_rx_dma(up, iir); + + if (!up->dma || dma_err) + status = serial8250_rx_chars(up, status); + } serial8250_modem_status(up); if (status & UART_LSR_THRE) serial8250_tx_chars(up); @@ -2121,6 +2129,18 @@ dont_test_tx_en: up->msr_saved_flags = 0; /* + * Request DMA channels for both RX and TX. + */ + if (up->dma) { + retval = serial8250_request_dma(up); + if (retval) { + pr_warn_ratelimited("ttyS%d - failed to request DMA\n", + serial_index(port)); + up->dma = NULL; + } + } + + /* * Finally, enable interrupts. Note: Modem status interrupts * are set via set_termios(), which will be occurring imminently * anyway, so we don't enable them here. @@ -2153,6 +2173,9 @@ static void serial8250_shutdown(struct uart_port *port) up->ier = 0; serial_port_out(port, UART_IER, 0); + if (up->dma) + serial8250_release_dma(up); + spin_lock_irqsave(&port->lock, flags); if (port->flags & UPF_FOURPORT) { /* reset interrupts on the AST Fourport board */ @@ -3217,6 +3240,8 @@ int serial8250_register_8250_port(struct uart_8250_port *up) uart->dl_read = up->dl_read; if (up->dl_write) uart->dl_write = up->dl_write; + if (up->dma) + uart->dma = up->dma; if (serial8250_isa_config != NULL) serial8250_isa_config(0, &uart->port, diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index 3b4ea84898c2..363d549d2e0d 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -12,6 +12,35 @@ */ #include <linux/serial_8250.h> +#include <linux/dmaengine.h> + +struct uart_8250_dma { + dma_filter_fn fn; + void *rx_param; + void *tx_param; + + int rx_chan_id; + int tx_chan_id; + + struct dma_slave_config rxconf; + struct dma_slave_config txconf; + + struct dma_chan *rxchan; + struct dma_chan *txchan; + + dma_addr_t rx_addr; + dma_addr_t tx_addr; + + dma_cookie_t rx_cookie; + dma_cookie_t tx_cookie; + + void *rx_buf; + + size_t rx_size; + size_t tx_size; + + unsigned char tx_running:1; +}; struct old_serial_port { unsigned int uart; @@ -142,3 +171,24 @@ static inline int is_omap1510_8250(struct uart_8250_port *pt) return 0; } #endif + +#ifdef CONFIG_SERIAL_8250_DMA +extern int serial8250_tx_dma(struct uart_8250_port *); +extern int serial8250_rx_dma(struct uart_8250_port *, unsigned int iir); +extern int serial8250_request_dma(struct uart_8250_port *); +extern void serial8250_release_dma(struct uart_8250_port *); +#else +static inline int serial8250_tx_dma(struct uart_8250_port *p) +{ + return -1; +} +static inline int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir) +{ + return -1; +} +static inline int serial8250_request_dma(struct uart_8250_port *p) +{ + return -1; +} +static inline void serial8250_release_dma(struct uart_8250_port *p) { } +#endif diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c new file mode 100644 index 000000000000..95516a15a441 --- /dev/null +++ b/drivers/tty/serial/8250/8250_dma.c @@ -0,0 +1,213 @@ +/* + * 8250_dma.c - DMA Engine API support for 8250.c + * + * Copyright (C) 2013 Intel Corporation + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/serial_reg.h> +#include <linux/dma-mapping.h> + +#include "8250.h" + +static void __dma_tx_complete(void *param) +{ + struct uart_8250_port *p = param; + struct uart_8250_dma *dma = p->dma; + struct circ_buf *xmit = &p->port.state->xmit; + + dma->tx_running = 0; + + dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr, + UART_XMIT_SIZE, DMA_TO_DEVICE); + + xmit->tail += dma->tx_size; + xmit->tail &= UART_XMIT_SIZE - 1; + p->port.icount.tx += dma->tx_size; + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(&p->port); + + if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) { + serial8250_tx_dma(p); + uart_write_wakeup(&p->port); + } +} + +static void __dma_rx_complete(void *param) +{ + struct uart_8250_port *p = param; + struct uart_8250_dma *dma = p->dma; + struct tty_struct *tty = p->port.state->port.tty; + struct dma_tx_state state; + + dma_sync_single_for_cpu(dma->rxchan->device->dev, dma->rx_addr, + dma->rx_size, DMA_FROM_DEVICE); + + dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + dmaengine_terminate_all(dma->rxchan); + + tty_insert_flip_string(tty, dma->rx_buf, dma->rx_size - state.residue); + p->port.icount.rx += dma->rx_size - state.residue; + + tty_flip_buffer_push(tty); +} + +int serial8250_tx_dma(struct uart_8250_port *p) +{ + struct uart_8250_dma *dma = p->dma; + struct circ_buf *xmit = &p->port.state->xmit; + struct dma_async_tx_descriptor *desc; + + if (dma->tx_running) { + uart_write_wakeup(&p->port); + return -EBUSY; + } + + dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); + + desc = dmaengine_prep_slave_single(dma->txchan, + dma->tx_addr + xmit->tail, + dma->tx_size, DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) + return -EBUSY; + + dma->tx_running = 1; + + desc->callback = __dma_tx_complete; + desc->callback_param = p; + + dma->tx_cookie = dmaengine_submit(desc); + + dma_sync_single_for_device(dma->txchan->device->dev, dma->tx_addr, + UART_XMIT_SIZE, DMA_TO_DEVICE); + + dma_async_issue_pending(dma->txchan); + + return 0; +} +EXPORT_SYMBOL_GPL(serial8250_tx_dma); + +int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir) +{ + struct uart_8250_dma *dma = p->dma; + struct dma_async_tx_descriptor *desc; + struct dma_tx_state state; + int dma_status; + + /* + * If RCVR FIFO trigger level was not reached, complete the transfer and + * let 8250.c copy the remaining data. + */ + if ((iir & 0x3f) == UART_IIR_RX_TIMEOUT) { + dma_status = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, + &state); + if (dma_status == DMA_IN_PROGRESS) { + dmaengine_pause(dma->rxchan); + __dma_rx_complete(p); + } + return -ETIMEDOUT; + } + + desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr, + dma->rx_size, DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) + return -EBUSY; + + desc->callback = __dma_rx_complete; + desc->callback_param = p; + + dma->rx_cookie = dmaengine_submit(desc); + + dma_sync_single_for_device(dma->rxchan->device->dev, dma->rx_addr, + dma->rx_size, DMA_FROM_DEVICE); + + dma_async_issue_pending(dma->rxchan); + + return 0; +} +EXPORT_SYMBOL_GPL(serial8250_rx_dma); + +int serial8250_request_dma(struct uart_8250_port *p) +{ + struct uart_8250_dma *dma = p->dma; + dma_cap_mask_t mask; + + dma->rxconf.src_addr = p->port.mapbase + UART_RX; + dma->txconf.dst_addr = p->port.mapbase + UART_TX; + + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + + /* Get a channel for RX */ + dma->rxchan = dma_request_channel(mask, dma->fn, dma->rx_param); + if (!dma->rxchan) + return -ENODEV; + + dmaengine_slave_config(dma->rxchan, &dma->rxconf); + + /* Get a channel for TX */ + dma->txchan = dma_request_channel(mask, dma->fn, dma->tx_param); + if (!dma->txchan) { + dma_release_channel(dma->rxchan); + return -ENODEV; + } + + dmaengine_slave_config(dma->txchan, &dma->txconf); + + /* RX buffer */ + if (!dma->rx_size) + dma->rx_size = PAGE_SIZE; + + dma->rx_buf = dma_alloc_coherent(dma->rxchan->device->dev, dma->rx_size, + &dma->rx_addr, GFP_KERNEL); + if (!dma->rx_buf) { + dma_release_channel(dma->rxchan); + dma_release_channel(dma->txchan); + return -ENOMEM; + } + + /* TX buffer */ + dma->tx_addr = dma_map_single(dma->txchan->device->dev, + p->port.state->xmit.buf, + UART_XMIT_SIZE, + DMA_TO_DEVICE); + + dev_dbg_ratelimited(p->port.dev, "got both dma channels\n"); + + return 0; +} +EXPORT_SYMBOL_GPL(serial8250_request_dma); + +void serial8250_release_dma(struct uart_8250_port *p) +{ + struct uart_8250_dma *dma = p->dma; + + if (!dma) + return; + + /* Release RX resources */ + dmaengine_terminate_all(dma->rxchan); + dma_free_coherent(dma->rxchan->device->dev, dma->rx_size, dma->rx_buf, + dma->rx_addr); + dma_release_channel(dma->rxchan); + dma->rxchan = NULL; + + /* Release TX resources */ + dmaengine_terminate_all(dma->txchan); + dma_unmap_single(dma->txchan->device->dev, dma->tx_addr, + UART_XMIT_SIZE, DMA_TO_DEVICE); + dma_release_channel(dma->txchan); + dma->txchan = NULL; + dma->tx_running = 0; + + dev_dbg_ratelimited(p->port.dev, "dma channels released\n"); +} +EXPORT_SYMBOL_GPL(serial8250_release_dma); diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig index 3ce3e7533e4c..d31f4c63d4ba 100644 --- a/drivers/tty/serial/8250/Kconfig +++ b/drivers/tty/serial/8250/Kconfig @@ -84,6 +84,14 @@ config SERIAL_8250_GSC depends on SERIAL_8250 && GSC default SERIAL_8250 +config SERIAL_8250_DMA + bool "DMA support for 16550 compatible UART controllers" if EXPERT + depends on SERIAL_8250 && DMADEVICES=y + default SERIAL_8250 + help + This builds DMA support that can be used with 8250/16650 + compatible UART controllers that support DMA signaling. + config SERIAL_8250_PCI tristate "8250/16550 PCI device support" if EXPERT depends on SERIAL_8250 && PCI diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile index 108fe7fe13e2..a23838a4d535 100644 --- a/drivers/tty/serial/8250/Makefile +++ b/drivers/tty/serial/8250/Makefile @@ -5,6 +5,7 @@ obj-$(CONFIG_SERIAL_8250) += 8250_core.o 8250_core-y := 8250.o 8250_core-$(CONFIG_SERIAL_8250_PNP) += 8250_pnp.o +8250_core-$(CONFIG_SERIAL_8250_DMA) += 8250_dma.o obj-$(CONFIG_SERIAL_8250_GSC) += 8250_gsc.o obj-$(CONFIG_SERIAL_8250_PCI) += 8250_pci.o obj-$(CONFIG_SERIAL_8250_HP300) += 8250_hp300.o |