lkml.org 
[lkml]   [2011]   [Feb]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/8] pch_uart: add multi-scatter processing
Date
Currently, this driver can handle only single scatterlist.
Thus, it can't send data beyond FIFO size.

This patch enables this driver can handle multiple scatter list.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
---
drivers/serial/pch_uart.c | 117 ++++++++++++++++++++++++++++++++++-----------
1 files changed, 89 insertions(+), 28 deletions(-)
diff --git a/drivers/serial/pch_uart.c b/drivers/serial/pch_uart.c
index 3b2fb93..c1386eb 100644
--- a/drivers/serial/pch_uart.c
+++ b/drivers/serial/pch_uart.c
@@ -226,7 +226,8 @@ struct eg20t_port {
struct pch_dma_slave param_rx;
struct dma_chan *chan_tx;
struct dma_chan *chan_rx;
- struct scatterlist sg_tx;
+ struct scatterlist *sg_tx_p;
+ int nent;
struct scatterlist sg_rx;
int tx_dma_use;
void *rx_buf_virt;
@@ -595,16 +596,20 @@ static void pch_dma_rx_complete(void *arg)
struct eg20t_port *priv = arg;
struct uart_port *port = &priv->port;
struct tty_struct *tty = tty_port_tty_get(&port->state->port);
+ int count;

if (!tty) {
pr_debug("%s:tty is busy now", __func__);
return;
}

- if (dma_push_rx(priv, priv->trigger_level))
+ dma_sync_sg_for_cpu(port->dev, &priv->sg_rx, 1, DMA_FROM_DEVICE);
+ count = dma_push_rx(priv, priv->trigger_level);
+ if (count)
tty_flip_buffer_push(tty);
-
tty_kref_put(tty);
+ async_tx_ack(priv->desc_rx);
+ pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_RX_INT);
}

static void pch_dma_tx_complete(void *arg)
@@ -612,13 +617,21 @@ static void pch_dma_tx_complete(void *arg)
struct eg20t_port *priv = arg;
struct uart_port *port = &priv->port;
struct circ_buf *xmit = &port->state->xmit;
+ struct scatterlist *sg = priv->sg_tx_p;
+ int i;

- xmit->tail += sg_dma_len(&priv->sg_tx);
+ for (i = 0; i < priv->nent; i++, sg++) {
+ xmit->tail += sg_dma_len(sg);
+ port->icount.tx += sg_dma_len(sg);
+ }
xmit->tail &= UART_XMIT_SIZE - 1;
- port->icount.tx += sg_dma_len(&priv->sg_tx);
-
async_tx_ack(priv->desc_tx);
+ dma_unmap_sg(port->dev, sg, priv->nent, DMA_TO_DEVICE);
priv->tx_dma_use = 0;
+ priv->nent = 0;
+ kfree(priv->sg_tx_p);
+ if (uart_circ_chars_pending(xmit))
+ pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_TX_INT);
}

static int pop_tx(struct eg20t_port *priv, unsigned char *buf, int size)
@@ -682,7 +695,7 @@ static int dma_handle_rx(struct eg20t_port *priv)

sg_init_table(&priv->sg_rx, 1); /* Initialize SG table */

- sg_dma_len(sg) = priv->fifo_size;
+ sg_dma_len(sg) = priv->trigger_level;

sg_set_page(&priv->sg_rx, virt_to_page(priv->rx_buf_virt),
sg_dma_len(sg), (unsigned long)priv->rx_buf_virt &
@@ -692,7 +705,8 @@ static int dma_handle_rx(struct eg20t_port *priv)

desc = priv->chan_rx->device->device_prep_slave_sg(priv->chan_rx,
sg, 1, DMA_FROM_DEVICE,
- DMA_PREP_INTERRUPT);
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+
if (!desc)
return 0;

@@ -731,6 +745,9 @@ static unsigned int handle_tx(struct eg20t_port *priv)
fifo_size--;
}
size = min(xmit->head - xmit->tail, fifo_size);
+ if (size < 0)
+ size = fifo_size;
+
tx_size = pop_tx(priv, xmit->buf, size);
if (tx_size > 0) {
ret = pch_uart_hal_write(priv, xmit->buf, tx_size);
@@ -740,8 +757,10 @@ static unsigned int handle_tx(struct eg20t_port *priv)

priv->tx_empty = tx_empty;

- if (tx_empty)
+ if (tx_empty) {
pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_TX_INT);
+ uart_write_wakeup(port);
+ }

return PCH_UART_HANDLED_TX_INT;
}
@@ -750,11 +769,16 @@ static unsigned int dma_handle_tx(struct eg20t_port *priv)
{
struct uart_port *port = &priv->port;
struct circ_buf *xmit = &port->state->xmit;
- struct scatterlist *sg = &priv->sg_tx;
+ struct scatterlist *sg;
int nent;
int fifo_size;
int tx_empty;
struct dma_async_tx_descriptor *desc;
+ int num;
+ int i;
+ int bytes;
+ int size;
+ int rem;

if (!priv->start_tx) {
pr_info("%s:Tx isn't started. (%lu)\n", __func__, jiffies);
@@ -772,37 +796,68 @@ static unsigned int dma_handle_tx(struct eg20t_port *priv)
fifo_size--;
}

- pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_TX_INT);
+ bytes = min((int)CIRC_CNT(xmit->head, xmit->tail,
+ UART_XMIT_SIZE), CIRC_CNT_TO_END(xmit->head,
+ xmit->tail, UART_XMIT_SIZE));
+ if (!bytes) {
+ pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_TX_INT);
+ uart_write_wakeup(port);
+ return 0;
+ }
+
+ if (bytes > fifo_size) {
+ num = bytes / fifo_size + 1;
+ size = fifo_size;
+ rem = bytes % fifo_size;
+ } else {
+ num = 1;
+ size = bytes;
+ rem = bytes;
+ }

priv->tx_dma_use = 1;

- sg_init_table(&priv->sg_tx, 1); /* Initialize SG table */
+ priv->sg_tx_p = kzalloc(sizeof(struct scatterlist)*num, GFP_ATOMIC);
+
+ sg_init_table(priv->sg_tx_p, num); /* Initialize SG table */
+ sg = priv->sg_tx_p;

- sg_set_page(&priv->sg_tx, virt_to_page(xmit->buf),
- UART_XMIT_SIZE, (int)xmit->buf & ~PAGE_MASK);
+ for (i = 0; i < num; i++, sg++) {
+ if (i == (num - 1))
+ sg_set_page(sg, virt_to_page(xmit->buf),
+ rem, fifo_size * i);
+ else
+ sg_set_page(sg, virt_to_page(xmit->buf),
+ size, fifo_size * i);
+ }

- nent = dma_map_sg(port->dev, &priv->sg_tx, 1, DMA_TO_DEVICE);
+ sg = priv->sg_tx_p;
+ nent = dma_map_sg(port->dev, sg, num, DMA_TO_DEVICE);
if (!nent) {
pr_err("%s:dma_map_sg Failed\n", __func__);
return 0;
}
-
- sg->offset = xmit->tail & (UART_XMIT_SIZE - 1);
- sg_dma_address(sg) = (sg_dma_address(sg) & ~(UART_XMIT_SIZE - 1)) +
- sg->offset;
- sg_dma_len(sg) = min((int)CIRC_CNT(xmit->head, xmit->tail,
- UART_XMIT_SIZE), CIRC_CNT_TO_END(xmit->head,
- xmit->tail, UART_XMIT_SIZE));
+ priv->nent = nent;
+
+ for (i = 0; i < nent; i++, sg++) {
+ sg->offset = (xmit->tail & (UART_XMIT_SIZE - 1)) +
+ fifo_size * i;
+ sg_dma_address(sg) = (sg_dma_address(sg) &
+ ~(UART_XMIT_SIZE - 1)) + sg->offset;
+ if (i == (nent - 1))
+ sg_dma_len(sg) = rem;
+ else
+ sg_dma_len(sg) = size;
+ }

desc = priv->chan_tx->device->device_prep_slave_sg(priv->chan_tx,
- sg, nent, DMA_TO_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ priv->sg_tx_p, nent, DMA_TO_DEVICE,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
pr_err("%s:device_prep_slave_sg Failed\n", __func__);
return 0;
}
-
- dma_sync_sg_for_device(port->dev, sg, 1, DMA_TO_DEVICE);
-
+ dma_sync_sg_for_device(port->dev, priv->sg_tx_p, nent, DMA_TO_DEVICE);
priv->desc_tx = desc;
desc->callback = pch_dma_tx_complete;
desc->callback_param = priv;
@@ -857,10 +912,16 @@ static irqreturn_t pch_uart_interrupt(int irq, void *dev_id)
}
break;
case PCH_UART_IID_RDR: /* Received Data Ready */
- if (priv->use_dma)
+ if (priv->use_dma) {
+ pch_uart_hal_disable_interrupt(priv,
+ PCH_UART_HAL_RX_INT);
ret = dma_handle_rx(priv);
- else
+ if (!ret)
+ pch_uart_hal_enable_interrupt(priv,
+ PCH_UART_HAL_RX_INT);
+ } else {
ret = handle_rx(priv);
+ }
break;
case PCH_UART_IID_RDR_TO: /* Received Data Ready
(FIFO Timeout) */
--
1.7.3.4


\
 
 \ /
  Last update: 2011-02-18 03:25    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site