Support using DMA for sending and receiving data over SCI(F) interfaces of
various SH SoCs.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
---
Tested on Migo-R (sh7722), partially on ms7724se (sh7724), the latter
seems to be unable to use DMA with SCIFA ports (3-5).
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 9a8e9f0..52f28e1 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -1016,6 +1016,12 @@ config SERIAL_SH_SCI_CONSOLE
depends on SERIAL_SH_SCI=y
select SERIAL_CORE_CONSOLE
+config SH_SCI_USE_DMA
+ bool "DMA support"
+ depends on SERIAL_SH_SCI
+ select DMADEVICES
+ select SH_DMAE
+
config SERIAL_PNX8XXX
bool "Enable PNX8XXX SoCs' UART Support"
depends on MIPS && (SOC_PNX8550 || SOC_PNX833X)
diff --git a/drivers/serial/sh-sci.c b/drivers/serial/sh-sci.c
index 2cf3b6d..36e608e 100644
--- a/drivers/serial/sh-sci.c
+++ b/drivers/serial/sh-sci.c
@@ -48,6 +48,9 @@
#include <linux/ctype.h>
#include <linux/err.h>
#include <linux/list.h>
+#include <linux/dmaengine.h>
+#include <linux/scatterlist.h>
+#include <linux/timer.h>
#ifdef CONFIG_SUPERH
#include <asm/sh_bios.h>
@@ -84,6 +87,27 @@ struct sci_port {
struct clk *dclk;
struct list_head node;
+ struct dma_chan *chan_tx;
+ struct dma_chan *chan_rx;
+#ifdef CONFIG_SH_SCI_USE_DMA
+ struct device *dma_dev;
+ enum sh_dmae_slave_chan_id slave_tx;
+ enum sh_dmae_slave_chan_id slave_rx;
+ struct dma_async_tx_descriptor *desc_tx;
+ struct dma_async_tx_descriptor *desc_rx[2];
+ dma_cookie_t cookie_tx;
+ dma_cookie_t cookie_rx[2];
+ dma_cookie_t active_rx;
+ struct scatterlist sg_tx;
+ unsigned int sg_len_tx;
+ struct scatterlist sg_rx[2];
+ size_t buf_len_rx;
+ struct sh_dmae_slave param_tx;
+ struct sh_dmae_slave param_rx;
+ struct work_struct work_tx;
+ struct work_struct work_rx;
+ struct timer_list rx_timer;
+#endif
};
struct sh_sci_priv {
@@ -273,29 +297,44 @@ static inline void sci_init_pins(struct uart_port *port, unsigned int cflag)
defined(CONFIG_CPU_SUBTYPE_SH7780) || \
defined(CONFIG_CPU_SUBTYPE_SH7785) || \
defined(CONFIG_CPU_SUBTYPE_SH7786)
-static inline int scif_txroom(struct uart_port *port)
+static int scif_txfill(struct uart_port *port)
{
- return SCIF_TXROOM_MAX - (sci_in(port, SCTFDR) & 0xff);
+ return sci_in(port, SCTFDR) & 0xff;
}
-static inline int scif_rxroom(struct uart_port *port)
+static int scif_txroom(struct uart_port *port)
+{
+ return SCIF_TXROOM_MAX - scif_txfill(port);
+}
+
+static int scif_rxfill(struct uart_port *port)
{
return sci_in(port, SCRFDR) & 0xff;
}
#elif defined(CONFIG_CPU_SUBTYPE_SH7763)
-static inline int scif_txroom(struct uart_port *port)
+static int scif_txfill(struct uart_port *port)
{
- if ((port->mapbase == 0xffe00000) ||
- (port->mapbase == 0xffe08000)) {
+ if (port->mapbase == 0xffe00000 ||
+ port->mapbase == 0xffe08000)
/* SCIF0/1*/
- return SCIF_TXROOM_MAX - (sci_in(port, SCTFDR) & 0xff);
- } else {
+ return sci_in(port, SCTFDR) & 0xff;
+ else
/* SCIF2 */
- return SCIF2_TXROOM_MAX - (sci_in(port, SCFDR) >> 8);
- }
+ return sci_in(port, SCFDR) >> 8;
+}
+
+static int scif_txroom(struct uart_port *port)
+{
+ if (port->mapbase == 0xffe00000 ||
+ port->mapbase == 0xffe08000)
+ /* SCIF0/1*/
+ return SCIF_TXROOM_MAX - scif_txfill(port);
+ else
+ /* SCIF2 */
+ return SCIF2_TXROOM_MAX - scif_txfill(port);
}
-static inline int scif_rxroom(struct uart_port *port)
+static int scif_rxfill(struct uart_port *port)
{
if ((port->mapbase == 0xffe00000) ||
(port->mapbase == 0xffe08000)) {
@@ -307,23 +346,33 @@ static inline int scif_rxroom(struct uart_port *port)
}
}
#else
-static inline int scif_txroom(struct uart_port *port)
+static int scif_txfill(struct uart_port *port)
{
- return SCIF_TXROOM_MAX - (sci_in(port, SCFDR) >> 8);
+ return sci_in(port, SCFDR) >> 8;
}
-static inline int scif_rxroom(struct uart_port *port)
+static int scif_txroom(struct uart_port *port)
+{
+ return SCIF_TXROOM_MAX - scif_txfill(port);
+}
+
+static int scif_rxfill(struct uart_port *port)
{
return sci_in(port, SCFDR) & SCIF_RFDC_MASK;
}
#endif
-static inline int sci_txroom(struct uart_port *port)
+static int sci_txfill(struct uart_port *port)
{
- return (sci_in(port, SCxSR) & SCI_TDRE) != 0;
+ return !(sci_in(port, SCxSR) & SCI_TDRE);
}
-static inline int sci_rxroom(struct uart_port *port)
+static int sci_txroom(struct uart_port *port)
+{
+ return !sci_txfill(port);
+}
+
+static int sci_rxfill(struct uart_port *port)
{
return (sci_in(port, SCxSR) & SCxSR_RDxF(port)) != 0;
}
@@ -410,9 +459,9 @@ static inline void sci_receive_chars(struct uart_port *port)
while (1) {
if (port->type == PORT_SCI)
- count = sci_rxroom(port);
+ count = sci_rxfill(port);
else
- count = scif_rxroom(port);
+ count = scif_rxfill(port);
/* Don't copy more bytes than there is room for in the buffer */
count = tty_buffer_request_room(tty, count);
@@ -457,10 +506,10 @@ static inline void sci_receive_chars(struct uart_port *port)
}
/* Store data and status */
- if (status&SCxSR_FER(port)) {
+ if (status & SCxSR_FER(port)) {
flag = TTY_FRAME;
dev_notice(port->dev, "frame error\n");
- } else if (status&SCxSR_PER(port)) {
+ } else if (status & SCxSR_PER(port)) {
flag = TTY_PARITY;
dev_notice(port->dev, "parity error\n");
} else
@@ -622,13 +671,39 @@ static inline int sci_handle_breaks(struct uart_port *port)
return copied;
}
-static irqreturn_t sci_rx_interrupt(int irq, void *port)
+static irqreturn_t sci_rx_interrupt(int irq, void *ptr)
{
+#ifdef CONFIG_SH_SCI_USE_DMA
+ struct uart_port *port = ptr;
+ struct sci_port *s = to_sci_port(port);
+
+ if (s->chan_rx) {
+ unsigned long tout;
+ u16 scr = sci_in(port, SCSCR);
+ u16 ssr = sci_in(port, SCxSR);
+
+ /* Disable future Rx interrupts */
+ sci_out(port, SCSCR, scr & ~SCI_CTRL_FLAGS_RIE);
+ /* Clear current interrupt */
+ sci_out(port, SCxSR, ssr & ~(1 | SCxSR_RDxF(port)));
+ /* Calculate delay for 1.5 DMA buffers */
+ tout = (port->timeout - HZ / 50) * s->buf_len_rx * 3 /
+ port->fifosize / 2;
+ dev_dbg(port->dev, "Rx IRQ: setup timeout in %u ms\n",
+ tout * 1000 / HZ);
+ if (tout < 2)
+ tout = 2;
+ mod_timer(&s->rx_timer, jiffies + tout);
+
+ return IRQ_HANDLED;
+ }
+#endif
+
/* I think sci_receive_chars has to be called irrespective
* of whether the I_IXOFF is set, otherwise, how is the interrupt
* to be disabled?
*/
- sci_receive_chars(port);
+ sci_receive_chars(ptr);
return IRQ_HANDLED;
}
@@ -684,6 +759,9 @@ static irqreturn_t sci_mpxed_interrupt(int irq, void *ptr)
{
unsigned short ssr_status, scr_status, err_enabled;
struct uart_port *port = ptr;
+#ifdef CONFIG_SH_SCI_USE_DMA
+ struct sci_port *s = to_sci_port(port);
+#endif
irqreturn_t ret = IRQ_NONE;
ssr_status = sci_in(port, SCxSR);
@@ -691,10 +769,15 @@ static irqreturn_t sci_mpxed_interrupt(int irq, void *ptr)
err_enabled = scr_status & (SCI_CTRL_FLAGS_REIE | SCI_CTRL_FLAGS_RIE);
/* Tx Interrupt */
- if ((ssr_status & SCxSR_TDxE(port)) && (scr_status & SCI_CTRL_FLAGS_TIE))
+ if ((ssr_status & SCxSR_TDxE(port)) && (scr_status & SCI_CTRL_FLAGS_TIE) &&
+ !s->chan_tx)
ret = sci_tx_interrupt(irq, ptr);
- /* Rx Interrupt */
- if ((ssr_status & SCxSR_RDxF(port)) && (scr_status & SCI_CTRL_FLAGS_RIE))
+ /*
+ * Rx Interrupt: if we're using DMA, the DMA controller clears RDF /
+ * DR flags
+ */
+ if (((ssr_status & SCxSR_RDxF(port)) || s->chan_rx) &&
+ (scr_status & SCI_CTRL_FLAGS_RIE))
ret = sci_rx_interrupt(irq, ptr);
/* Error Interrupt */
if ((ssr_status & SCxSR_ERRORS(port)) && err_enabled)
@@ -703,6 +786,10 @@ static irqreturn_t sci_mpxed_interrupt(int irq, void *ptr)
if ((ssr_status & SCxSR_BRK(port)) && err_enabled)
ret = sci_br_interrupt(irq, ptr);
+ WARN_ONCE(ret == IRQ_NONE,
+ "%s: %d IRQ %d, status %x, control %x\n", __func__,
+ irq, port->line, ssr_status, scr_status);
+
return ret;
}
@@ -804,7 +891,9 @@ static void sci_free_irq(struct sci_port *port)
static unsigned int sci_tx_empty(struct uart_port *port)
{
unsigned short status = sci_in(port, SCxSR);
- return status & SCxSR_TEND(port) ? TIOCSER_TEMT : 0;
+ unsigned short in_tx_fifo = scif_txfill(port);
+
+ return (status & SCxSR_TEND(port)) && !in_tx_fifo ? TIOCSER_TEMT : 0;
}
static void sci_set_mctrl(struct uart_port *port, unsigned int mctrl)
@@ -816,16 +905,301 @@ static void sci_set_mctrl(struct uart_port *port, unsigned int mctrl)
static unsigned int sci_get_mctrl(struct uart_port *port)
{
- /* This routine is used for geting signals of: DTR, DCD, DSR, RI,
+ /* This routine is used for getting signals of: DTR, DCD, DSR, RI,
and CTS/RTS */
return TIOCM_DTR | TIOCM_RTS | TIOCM_DSR;
}
+#ifdef CONFIG_SH_SCI_USE_DMA
+static void sci_dma_tx_complete(void *arg)
+{
+ struct sci_port *s = arg;
+ struct uart_port *port = &s->port;
+ struct circ_buf *xmit = &port->state->xmit;
+ unsigned long flags;
+
+ dev_dbg(port->dev, "%s(%d)\n", __func__, port->line);
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ xmit->tail += s->sg_tx.length;
+ xmit->tail &= UART_XMIT_SIZE - 1;
+
+ port->icount.tx += s->sg_tx.length;
+
+ async_tx_ack(s->desc_tx);
+ s->cookie_tx = -EINVAL;
+ s->desc_tx = NULL;
+
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(port);
+
+ if (uart_circ_chars_pending(xmit))
+ schedule_work(&s->work_tx);
+}
+
+/* Locking: called with port lock held */
+static int sci_dma_rx_push(struct sci_port *s, struct tty_struct *tty,
+ size_t count)
+{
+ struct uart_port *port = &s->port;
+ int i, active, room;
+
+ room = tty_buffer_request_room(tty, count);
+
+ if (s->active_rx == s->cookie_rx[0]) {
+ active = 0;
+ } else if (s->active_rx == s->cookie_rx[1]) {
+ active = 1;
+ } else {
+ dev_err(port->dev, "cookie %d not found!\n", s->active_rx);
+ return 0;
+ }
+
+ if (room < count)
+ dev_warn(port->dev, "Rx overrun: dropping %u bytes\n",
+ count - room);
+ if (!room)
+ return room;
+
+ for (i = 0; i < room; i++)
+ tty_insert_flip_char(tty, ((u8 *)sg_virt(&s->sg_rx[active]))[i],
+ TTY_NORMAL);
+
+ port->icount.rx += room;
+
+ return room;
+}
+
+static void sci_dma_rx_complete(void *arg)
+{
+ struct sci_port *s = arg;
+ struct uart_port *port = &s->port;
+ struct tty_struct *tty = port->state->port.tty;
+ unsigned long flags;
+ int count;
+
+ dev_dbg(port->dev, "%s(%d)\n", __func__, port->line);
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ count = sci_dma_rx_push(s, tty, s->buf_len_rx);
+
+ mod_timer(&s->rx_timer, jiffies + msecs_to_jiffies(5));
+
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ if (count)
+ tty_flip_buffer_push(tty);
+
+ schedule_work(&s->work_rx);
+}
+
+static void sci_start_rx(struct uart_port *port);
+static void sci_start_tx(struct uart_port *port);
+
+static void sci_rx_dma_release(struct sci_port *s, bool enable_pio)
+{
+ struct dma_chan *chan = s->chan_rx;
+ struct uart_port *port = &s->port;
+ unsigned long flags;
+
+ s->chan_rx = NULL;
+ s->cookie_rx[0] = s->cookie_rx[1] = -EINVAL;
+ dma_release_channel(chan);
+ dma_free_coherent(port->dev, s->buf_len_rx * 2,
+ sg_virt(&s->sg_rx[0]), sg_dma_address(&s->sg_rx[0]));
+ if (enable_pio)
+ sci_start_rx(port);
+}
+
+static void sci_tx_dma_release(struct sci_port *s, bool enable_pio)
+{
+ struct dma_chan *chan = s->chan_tx;
+ struct uart_port *port = &s->port;
+ unsigned long flags;
+
+ s->chan_tx = NULL;
+ s->cookie_tx = -EINVAL;
+ dma_release_channel(chan);
+ if (enable_pio)
+ sci_start_tx(port);
+}
+
+static void sci_submit_rx(struct sci_port *s)
+{
+ struct dma_chan *chan = s->chan_rx;
+ int i;
+
+ for (i = 0; i < 2; i++) {
+ struct scatterlist *sg = &s->sg_rx[i];
+ struct dma_async_tx_descriptor *desc;
+
+ desc = chan->device->device_prep_slave_sg(chan,
+ sg, 1, DMA_FROM_DEVICE, DMA_PREP_INTERRUPT);
+
+ if (desc) {
+ s->desc_rx[i] = desc;
+ desc->callback = sci_dma_rx_complete;
+ desc->callback_param = s;
+ s->cookie_rx[i] = desc->tx_submit(desc);
+ }
+
+ if (!desc || s->cookie_rx[i] < 0) {
+ if (i) {
+ async_tx_ack(s->desc_rx[0]);
+ s->cookie_rx[0] = -EINVAL;
+ }
+ if (desc) {
+ async_tx_ack(desc);
+ s->cookie_rx[i] = -EINVAL;
+ }
+ dev_warn(s->port.dev,
+ "failed to re-start DMA, using PIO\n");
+ sci_rx_dma_release(s, true);
+ return;
+ }
+ }
+
+ s->active_rx = s->cookie_rx[0];
+
+ dma_async_issue_pending(chan);
+
+ return;
+}
+
+static void work_fn_rx(struct work_struct *work)
+{
+ struct sci_port *s = container_of(work, struct sci_port, work_rx);
+ struct uart_port *port = &s->port;
+ struct dma_async_tx_descriptor *desc;
+ int new;
+
+ if (s->active_rx == s->cookie_rx[0]) {
+ new = 0;
+ } else if (s->active_rx == s->cookie_rx[1]) {
+ new = 1;
+ } else {
+ dev_err(port->dev, "cookie %d not found!\n", s->active_rx);
+ return;
+ }
+ desc = s->desc_rx[new];
+
+ if (dma_async_is_tx_complete(s->chan_rx, s->active_rx, NULL, NULL) !=
+ DMA_SUCCESS) {
+ /* Handle incomplete DMA receive */
+ struct tty_struct *tty = port->state->port.tty;
+ struct dma_chan *chan = s->chan_rx;
+ struct sh_desc *sh_desc = container_of(desc, struct sh_desc,
+ async_tx);
+ unsigned long flags;
+ int count;
+
+ chan->device->device_terminate_all(chan);
+ dev_dbg(port->dev, "Read %u bytes with cookie %d\n",
+ sh_desc->partial, sh_desc->cookie);
+
+ spin_lock_irqsave(&port->lock, flags);
+ count = sci_dma_rx_push(s, tty, sh_desc->partial);
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ if (count)
+ tty_flip_buffer_push(tty);
+
+ sci_submit_rx(s);
+
+ return;
+ }
+
+ s->cookie_rx[new] = desc->tx_submit(desc);
+ if (s->cookie_rx[new] < 0) {
+ dev_warn(port->dev, "Failed submitting Rx DMA descriptor\n");
+ sci_rx_dma_release(s, true);
+ return;
+ }
+
+ dev_dbg(port->dev, "%s: cookie %d #%d\n", __func__,
+ s->cookie_rx[new], new);
+
+ s->active_rx = s->cookie_rx[!new];
+}
+
+static void work_fn_tx(struct work_struct *work)
+{
+ struct sci_port *s = container_of(work, struct sci_port, work_tx);
+ struct dma_async_tx_descriptor *desc;
+ struct dma_chan *chan = s->chan_tx;
+ struct uart_port *port = &s->port;
+ struct circ_buf *xmit = &port->state->xmit;
+ struct scatterlist *sg = &s->sg_tx;
+
+ /*
+ * DMA is idle now.
+ * Port xmit buffer is already mapped, and it is one page... Just adjust
+ * offsets and lengths. Since it is a circular buffer, we have to
+ * transmit till the end, and then the rest. Take the port lock to get a
+ * consistent xmit buffer state.
+ */
+ spin_lock_irq(&port->lock);
+ sg->offset = xmit->tail & (UART_XMIT_SIZE - 1);
+ sg->dma_address = (sg_dma_address(sg) & ~(UART_XMIT_SIZE - 1)) +
+ sg->offset;
+ sg->length = min((int)CIRC_CNT(xmit->head, xmit->tail, UART_XMIT_SIZE),
+ CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE));
+ sg->dma_length = sg->length;
+ spin_unlock_irq(&port->lock);
+
+ BUG_ON(!sg->length);
+
+ desc = chan->device->device_prep_slave_sg(chan,
+ sg, s->sg_len_tx, DMA_TO_DEVICE,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!desc) {
+ /* switch to PIO */
+ sci_tx_dma_release(s, true);
+ return;
+ }
+
+ dma_sync_sg_for_device(port->dev, sg, 1, DMA_TO_DEVICE);
+
+ spin_lock_irq(&port->lock);
+ s->desc_tx = desc;
+ desc->callback = sci_dma_tx_complete;
+ desc->callback_param = s;
+ spin_unlock_irq(&port->lock);
+ s->cookie_tx = desc->tx_submit(desc);
+ if (s->cookie_tx < 0) {
+ dev_warn(port->dev, "Failed submitting Tx DMA descriptor\n");
+ /* switch to PIO */
+ sci_tx_dma_release(s, true);
+ return;
+ }
+
+ dev_dbg(port->dev, "%s: %p: %d...%d, cookie %d\n", __func__,
+ xmit->buf, xmit->tail, xmit->head, s->cookie_tx);
+
+ dma_async_issue_pending(chan);
+}
+#endif
+
static void sci_start_tx(struct uart_port *port)
{
unsigned short ctrl;
+#ifdef CONFIG_SH_SCI_USE_DMA
+ struct sci_port *s = to_sci_port(port);
+
+ if (s->chan_tx) {
+ if (!uart_circ_empty(&s->port.state->xmit) && s->cookie_tx < 0)
+ schedule_work(&s->work_tx);
+
+ return;
+ }
+#endif
+
/* Set TIE (Transmit Interrupt Enable) bit in SCSCR */
ctrl = sci_in(port, SCSCR);
ctrl |= SCI_CTRL_FLAGS_TIE;
@@ -842,13 +1216,12 @@ static void sci_stop_tx(struct uart_port *port)
sci_out(port, SCSCR, ctrl);
}
-static void sci_start_rx(struct uart_port *port, unsigned int tty_start)
+static void sci_start_rx(struct uart_port *port)
{
- unsigned short ctrl;
+ unsigned short ctrl = SCI_CTRL_FLAGS_RIE | SCI_CTRL_FLAGS_REIE;
/* Set RIE (Receive Interrupt Enable) bit in SCSCR */
- ctrl = sci_in(port, SCSCR);
- ctrl |= SCI_CTRL_FLAGS_RIE | SCI_CTRL_FLAGS_REIE;
+ ctrl |= sci_in(port, SCSCR);
sci_out(port, SCSCR, ctrl);
}
@@ -872,16 +1245,154 @@ static void sci_break_ctl(struct uart_port *port, int break_state)
/* Nothing here yet .. */
}
+#ifdef CONFIG_SH_SCI_USE_DMA
+static bool filter(struct dma_chan *chan, void *slave)
+{
+ struct sh_dmae_slave *param = slave;
+
+ dev_dbg(chan->device->dev, "%s: slave ID %d\n", __func__,
+ param->slave_id);
+
+ if (param->dma_dev == chan->device->dev) {
+ chan->private = param;
+ return true;
+ } else {
+ return false;
+ }
+}
+
+static void rx_timer_fn(unsigned long arg)
+{
+ struct sci_port *s = (struct sci_port *)arg;
+ struct uart_port *port = &s->port;
+
+ u16 scr = sci_in(port, SCSCR);
+ sci_out(port, SCSCR, scr | SCI_CTRL_FLAGS_RIE);
+ dev_dbg(port->dev, "DMA Rx timed out\n");
+ schedule_work(&s->work_rx);
+}
+
+static void sci_request_dma(struct uart_port *port)
+{
+ struct sci_port *s = to_sci_port(port);
+ struct sh_dmae_slave *param;
+ struct dma_chan *chan;
+ dma_cap_mask_t mask;
+ int nent;
+
+ dev_dbg(port->dev, "%s: port %d DMA %p\n", __func__,
+ port->line, s->dma_dev);
+
+ if (!s->dma_dev)
+ return;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+
+ param = &s->param_tx;
+
+ /* Slave ID, e.g., SHDMA_SLAVE_SCIF0_TX */
+ param->slave_id = s->slave_tx;
+ param->dma_dev = s->dma_dev;
+
+ s->cookie_tx = -EINVAL;
+ chan = dma_request_channel(mask, filter, param);
+ dev_dbg(port->dev, "%s: TX: got channel %p\n", __func__, chan);
+ if (chan) {
+ s->chan_tx = chan;
+ sg_init_table(&s->sg_tx, 1);
+ /* UART circular tx buffer is an aligned page. */
+ BUG_ON((int)port->state->xmit.buf & ~PAGE_MASK);
+ sg_set_page(&s->sg_tx, virt_to_page(port->state->xmit.buf),
+ UART_XMIT_SIZE, (int)port->state->xmit.buf & ~PAGE_MASK);
+ nent = dma_map_sg(port->dev, &s->sg_tx, 1, DMA_TO_DEVICE);
+ if (!nent)
+ sci_tx_dma_release(s, false);
+ else
+ dev_dbg(port->dev, "%s: mapped %d@%p to %x\n", __func__,
+ sg_dma_len(&s->sg_tx),
+ port->state->xmit.buf, sg_dma_address(&s->sg_tx));
+
+ s->sg_len_tx = nent;
+
+ INIT_WORK(&s->work_tx, work_fn_tx);
+ }
+
+ param = &s->param_rx;
+
+ /* Slave ID, e.g., SHDMA_SLAVE_SCIF0_RX */
+ param->slave_id = s->slave_rx;
+ param->dma_dev = s->dma_dev;
+
+ chan = dma_request_channel(mask, filter, param);
+ dev_dbg(port->dev, "%s: RX: got channel %p\n", __func__, chan);
+ if (chan) {
+ dma_addr_t dma[2];
+ void *buf[2];
+ int i;
+
+ s->chan_rx = chan;
+
+ s->buf_len_rx = 2 * max(16, (int)port->fifosize);
+ buf[0] = dma_alloc_coherent(port->dev, s->buf_len_rx * 2,
+ &dma[0], GFP_KERNEL);
+
+ if (!buf[0]) {
+ dev_warn(port->dev,
+ "failed to allocate dma buffer, using PIO\n");
+ sci_rx_dma_release(s, true);
+ return;
+ }
+
+ buf[1] = buf[0] + s->buf_len_rx;
+ dma[1] = dma[0] + s->buf_len_rx;
+
+ for (i = 0; i < 2; i++) {
+ struct scatterlist *sg = &s->sg_rx[i];
+
+ sg_init_table(sg, 1);
+ sg_set_page(sg, virt_to_page(buf[i]), s->buf_len_rx,
+ (int)buf[i] & ~PAGE_MASK);
+ sg->dma_address = dma[i];
+ sg->dma_length = sg->length;
+ }
+
+ INIT_WORK(&s->work_rx, work_fn_rx);
+ setup_timer(&s->rx_timer, rx_timer_fn, (unsigned long)s);
+
+ sci_submit_rx(s);
+ }
+}
+
+static void sci_free_dma(struct uart_port *port)
+{
+ struct sci_port *s = to_sci_port(port);
+
+ if (!s->dma_dev)
+ return;
+
+ if (s->chan_tx)
+ sci_tx_dma_release(s, false);
+ if (s->chan_rx)
+ sci_rx_dma_release(s, false);
+}
+#endif
+
static int sci_startup(struct uart_port *port)
{
struct sci_port *s = to_sci_port(port);
+ dev_dbg(port->dev, "%s(%d)\n", __func__, port->line);
+
if (s->enable)
s->enable(port);
sci_request_irq(s);
+#ifdef CONFIG_SH_SCI_USE_DMA
+ sci_request_dma(port);
+#endif
sci_start_tx(port);
- sci_start_rx(port, 1);
+ sci_start_rx(port);
return 0;
}
@@ -890,8 +1401,13 @@ static void sci_shutdown(struct uart_port *port)
{
struct sci_port *s = to_sci_port(port);
+ dev_dbg(port->dev, "%s(%d)\n", __func__, port->line);
+
sci_stop_rx(port);
sci_stop_tx(port);
+#ifdef CONFIG_SH_SCI_USE_DMA
+ sci_free_dma(port);
+#endif
sci_free_irq(s);
if (s->disable)
@@ -941,6 +1457,9 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
sci_out(port, SCSMR, smr_val);
+ dev_dbg(port->dev, "%s: SMR %x, t %x, SCSCR %x\n", __func__, smr_val, t,
+ SCSCR_INIT(port));
+
if (t > 0) {
if (t >= 256) {
sci_out(port, SCSMR, (sci_in(port, SCSMR) & ~3) | 1);
@@ -958,7 +1477,7 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
sci_out(port, SCSCR, SCSCR_INIT(port));
if ((termios->c_cflag & CREAD) != 0)
- sci_start_rx(port, 0);
+ sci_start_rx(port);
}
static const char *sci_type(struct uart_port *port)
@@ -1053,19 +1572,21 @@ static void __devinit sci_init_single(struct platform_device *dev,
unsigned int index,
struct plat_sci_port *p)
{
- sci_port->port.ops = &sci_uart_ops;
- sci_port->port.iotype = UPIO_MEM;
- sci_port->port.line = index;
+ struct uart_port *port = &sci_port->port;
+
+ port->ops = &sci_uart_ops;
+ port->iotype = UPIO_MEM;
+ port->line = index;
switch (p->type) {
case PORT_SCIFA:
- sci_port->port.fifosize = 64;
+ port->fifosize = 64;
break;
case PORT_SCIF:
- sci_port->port.fifosize = 16;
+ port->fifosize = 16;
break;
default:
- sci_port->port.fifosize = 1;
+ port->fifosize = 1;
break;
}
@@ -1074,19 +1595,28 @@ static void __devinit sci_init_single(struct platform_device *dev,
sci_port->dclk = clk_get(&dev->dev, "peripheral_clk");
sci_port->enable = sci_clk_enable;
sci_port->disable = sci_clk_disable;
- sci_port->port.dev = &dev->dev;
+ port->dev = &dev->dev;
}
sci_port->break_timer.data = (unsigned long)sci_port;
sci_port->break_timer.function = sci_break_timer;
init_timer(&sci_port->break_timer);
- sci_port->port.mapbase = p->mapbase;
- sci_port->port.membase = p->membase;
+ port->mapbase = p->mapbase;
+ port->membase = p->membase;
- sci_port->port.irq = p->irqs[SCIx_TXI_IRQ];
- sci_port->port.flags = p->flags;
- sci_port->type = sci_port->port.type = p->type;
+ port->irq = p->irqs[SCIx_TXI_IRQ];
+ port->flags = p->flags;
+ sci_port->type = port->type = p->type;
+
+#ifdef CONFIG_SH_SCI_USE_DMA
+ sci_port->dma_dev = p->dma_dev;
+ sci_port->slave_tx = p->dma_slave_tx;
+ sci_port->slave_rx = p->dma_slave_rx;
+
+ dev_dbg(port->dev, "%s: DMA device %p, tx %d, rx %d\n", __func__,
+ p->dma_dev, p->dma_slave_tx, p->dma_slave_rx);
+#endif
memcpy(&sci_port->irqs, &p->irqs, sizeof(p->irqs));
}
diff --git a/include/linux/serial_sci.h b/include/linux/serial_sci.h
index 1c297dd..1b177d2 100644
--- a/include/linux/serial_sci.h
+++ b/include/linux/serial_sci.h
@@ -2,6 +2,7 @@
#define __LINUX_SERIAL_SCI_H
#include <linux/serial_core.h>
+#include <asm/dmaengine.h>
/*
* Generic header for SuperH SCI(F) (used by sh/sh64/h8300 and related parts)
@@ -16,6 +17,8 @@ enum {
SCIx_NR_IRQS,
};
+struct device;
+
/*
* Platform device specific platform_data struct
*/
@@ -26,6 +29,9 @@ struct plat_sci_port {
unsigned int type; /* SCI / SCIF / IRDA */
upf_t flags; /* UPF_* flags */
char *clk; /* clock string */
+ struct device *dma_dev;
+ enum sh_dmae_slave_chan_id dma_slave_tx;
+ enum sh_dmae_slave_chan_id dma_slave_rx;
};
#endif /* __LINUX_SERIAL_SCI_H */
--
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