Commit 9ee4b83e authored by Heikki Krogerus's avatar Heikki Krogerus Committed by Greg Kroah-Hartman

serial: 8250: Add support for dmaengine

Add support for dmaengine API. The drivers can implement the
struct uart_8250_dma member in struct uart_8250_port and
8250.c can take care of the rest.
Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6a7320c4
......@@ -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);
......@@ -2120,6 +2128,18 @@ static int serial8250_startup(struct uart_port *port)
up->lsr_saved_flags = 0;
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
......@@ -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,
......
......@@ -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
/*
* 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);
......@@ -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
......
......@@ -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
......
......@@ -59,6 +59,8 @@ enum {
PLAT8250_DEV_SM501,
};
struct uart_8250_dma;
/*
* This should be used by drivers which want to register
* their own 8250 ports without registering their own
......@@ -91,6 +93,8 @@ struct uart_8250_port {
#define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
unsigned char msr_saved_flags;
struct uart_8250_dma *dma;
/* 8250 specific callbacks */
int (*dl_read)(struct uart_8250_port *);
void (*dl_write)(struct uart_8250_port *, int);
......
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