Re: [PATCH 5/5] atmel_serial: Add DMA support
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On Tue, 18 Dec 2007, Haavard Skinnemoen wrote: > From: Chip Coldwell <[EMAIL PROTECTED]> > > This patch is based on the DMA-patch by Chip Coldwell for the > AT91/AT32 serial USARTS, with some tweaks to make it apply neatly on > top of the other patches in this series. > > The RX code has been moved to a tasklet and reworked a bit. Instead of > depending on the ENDRX and TIMEOUT bits in CSR, we simply grab as much > data as we can from the DMA buffers. I think this closes a race where > the ENDRX bit is set after we read CSR but before we read RPR, > although I haven't confirmed this. > > This also fixes a DMA sync bug in the original patch. > > [EMAIL PROTECTED]: rebased onto irq-splitup patch] > [EMAIL PROTECTED]: moved to tasklet, fixed dma bug, misc cleanups] > Signed-off-by: Remy Bohmer <[EMAIL PROTECTED]> > Signed-off-by: Haavard Skinnemoen <[EMAIL PROTECTED]> > --- > drivers/serial/atmel_serial.c | 386 ++-- > 1 files changed, 366 insertions(+), 20 deletions(-) > > diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c > index 990d3ab..07c2734 100644 > --- a/drivers/serial/atmel_serial.c > +++ b/drivers/serial/atmel_serial.c > @@ -7,6 +7,8 @@ > * Based on drivers/char/serial_sa1100.c, by Deep Blue Solutions Ltd. > * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. > * > + * DMA support added by Chip Coldwell. I will ACK/Sign-off on this soon; I just want to do some tests on real hardware first. Chip - -- Charles M. Coldwell "Turn on, log in, tune out" Somerville, Massachusetts, New England -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.7 (GNU/Linux) iD8DBQFHaA7cr6maj4UuBS8RAjMSAJsGcKoFKCP/R3aAPhW5hj+v3Qt6ZACgshsF 5NP6/9+NbhDAxBC/7jo8J0Y= =hx4t -END PGP SIGNATURE- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 5/5] atmel_serial: Add DMA support
From: Chip Coldwell <[EMAIL PROTECTED]>
This patch is based on the DMA-patch by Chip Coldwell for the
AT91/AT32 serial USARTS, with some tweaks to make it apply neatly on
top of the other patches in this series.
The RX code has been moved to a tasklet and reworked a bit. Instead of
depending on the ENDRX and TIMEOUT bits in CSR, we simply grab as much
data as we can from the DMA buffers. I think this closes a race where
the ENDRX bit is set after we read CSR but before we read RPR,
although I haven't confirmed this.
This also fixes a DMA sync bug in the original patch.
[EMAIL PROTECTED]: rebased onto irq-splitup patch]
[EMAIL PROTECTED]: moved to tasklet, fixed dma bug, misc cleanups]
Signed-off-by: Remy Bohmer <[EMAIL PROTECTED]>
Signed-off-by: Haavard Skinnemoen <[EMAIL PROTECTED]>
---
drivers/serial/atmel_serial.c | 386 ++--
1 files changed, 366 insertions(+), 20 deletions(-)
diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index 990d3ab..07c2734 100644
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -7,6 +7,8 @@
* Based on drivers/char/serial_sa1100.c, by Deep Blue Solutions Ltd.
* Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
*
+ * DMA support added by Chip Coldwell.
+ *
* 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
@@ -33,6 +35,7 @@
#include
#include
#include
+#include
#include
#include
@@ -47,6 +50,11 @@
#include "atmel_serial.h"
+#define SUPPORT_PDC
+#define PDC_BUFFER_SIZE(L1_CACHE_BYTES << 3)
+#warning "Revisit"
+#define PDC_RX_TIMEOUT (3 * 10)/* 3 bytes */
+
#if defined(CONFIG_SERIAL_ATMEL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
@@ -111,6 +119,13 @@
static int (*atmel_open_hook) (struct uart_port *);
static void (*atmel_close_hook) (struct uart_port *);
+struct atmel_dma_buffer {
+ unsigned char *buf;
+ dma_addr_t dma_addr;
+ size_t dma_size;
+ unsigned intofs;
+};
+
struct atmel_uart_char {
u16 status;
u16 ch;
@@ -127,6 +142,13 @@ struct atmel_uart_port {
unsigned short suspended; /* is port suspended? */
int break_active; /* break being received */
+ short use_dma_rx; /* enable PDC receiver */
+ short pdc_rx_idx; /* current PDC RX buffer */
+ struct atmel_dma_buffer pdc_rx[2]; /* PDC receier */
+
+ short use_dma_tx; /* enable PDC transmitter */
+ struct atmel_dma_buffer pdc_tx; /* PDC transmitter */
+
struct tasklet_struct tasklet;
unsigned intirq_pending;
unsigned intirq_status;
@@ -136,10 +158,39 @@ struct atmel_uart_port {
static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART];
+#define PDC_RX_BUF(port) &(port)->pdc_rx[(port)->pdc_rx_idx]
+#define PDC_RX_SWITCH(port)(port)->pdc_rx_idx = !(port)->pdc_rx_idx
+
#ifdef SUPPORT_SYSRQ
static struct console atmel_console;
#endif
+#ifdef SUPPORT_PDC
+static bool atmel_use_dma_rx(struct uart_port *port)
+{
+ struct atmel_uart_port *atmel_port = (struct atmel_uart_port *)port;
+
+ return atmel_port->use_dma_rx;
+}
+
+static bool atmel_use_dma_tx(struct uart_port *port)
+{
+ struct atmel_uart_port *atmel_port = (struct atmel_uart_port *)port;
+
+ return atmel_port->use_dma_tx;
+}
+#else
+static bool atmel_use_dma_rx(struct uart_port *port)
+{
+ return false;
+}
+
+static bool atmel_use_dma_tx(struct uart_port *port)
+{
+ return false;
+}
+#endif
+
/*
* Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty.
*/
@@ -221,7 +272,12 @@ static u_int atmel_get_mctrl(struct uart_port *port)
*/
static void atmel_stop_tx(struct uart_port *port)
{
- UART_PUT_IDR(port, ATMEL_US_TXRDY);
+ if (atmel_use_dma_tx(port)) {
+ /* disable PDC transmit */
+ UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);
+ UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
+ } else
+ UART_PUT_IDR(port, ATMEL_US_TXRDY);
}
/*
@@ -229,7 +285,17 @@ static void atmel_stop_tx(struct uart_port *port)
*/
static void atmel_start_tx(struct uart_port *port)
{
- UART_PUT_IER(port, ATMEL_US_TXRDY);
+ if (atmel_use_dma_tx(port)) {
+ if (UART_GET_PTSR(port) & ATMEL_PDC_TXTEN)
+ /* The transmitter is already running. Yes, we
+ really need this.*/
+ return;
+
+ UART_PUT_IER(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
+ /* re-enable PDC transmit */
+
[PATCH 5/5] atmel_serial: Add DMA support
From: Chip Coldwell [EMAIL PROTECTED]
This patch is based on the DMA-patch by Chip Coldwell for the
AT91/AT32 serial USARTS, with some tweaks to make it apply neatly on
top of the other patches in this series.
The RX code has been moved to a tasklet and reworked a bit. Instead of
depending on the ENDRX and TIMEOUT bits in CSR, we simply grab as much
data as we can from the DMA buffers. I think this closes a race where
the ENDRX bit is set after we read CSR but before we read RPR,
although I haven't confirmed this.
This also fixes a DMA sync bug in the original patch.
[EMAIL PROTECTED]: rebased onto irq-splitup patch]
[EMAIL PROTECTED]: moved to tasklet, fixed dma bug, misc cleanups]
Signed-off-by: Remy Bohmer [EMAIL PROTECTED]
Signed-off-by: Haavard Skinnemoen [EMAIL PROTECTED]
---
drivers/serial/atmel_serial.c | 386 ++--
1 files changed, 366 insertions(+), 20 deletions(-)
diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index 990d3ab..07c2734 100644
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -7,6 +7,8 @@
* Based on drivers/char/serial_sa1100.c, by Deep Blue Solutions Ltd.
* Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
*
+ * DMA support added by Chip Coldwell.
+ *
* 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
@@ -33,6 +35,7 @@
#include linux/sysrq.h
#include linux/tty_flip.h
#include linux/platform_device.h
+#include linux/dma-mapping.h
#include linux/atmel_pdc.h
#include asm/io.h
@@ -47,6 +50,11 @@
#include atmel_serial.h
+#define SUPPORT_PDC
+#define PDC_BUFFER_SIZE(L1_CACHE_BYTES 3)
+#warning Revisit
+#define PDC_RX_TIMEOUT (3 * 10)/* 3 bytes */
+
#if defined(CONFIG_SERIAL_ATMEL_CONSOLE) defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
@@ -111,6 +119,13 @@
static int (*atmel_open_hook) (struct uart_port *);
static void (*atmel_close_hook) (struct uart_port *);
+struct atmel_dma_buffer {
+ unsigned char *buf;
+ dma_addr_t dma_addr;
+ size_t dma_size;
+ unsigned intofs;
+};
+
struct atmel_uart_char {
u16 status;
u16 ch;
@@ -127,6 +142,13 @@ struct atmel_uart_port {
unsigned short suspended; /* is port suspended? */
int break_active; /* break being received */
+ short use_dma_rx; /* enable PDC receiver */
+ short pdc_rx_idx; /* current PDC RX buffer */
+ struct atmel_dma_buffer pdc_rx[2]; /* PDC receier */
+
+ short use_dma_tx; /* enable PDC transmitter */
+ struct atmel_dma_buffer pdc_tx; /* PDC transmitter */
+
struct tasklet_struct tasklet;
unsigned intirq_pending;
unsigned intirq_status;
@@ -136,10 +158,39 @@ struct atmel_uart_port {
static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART];
+#define PDC_RX_BUF(port) (port)-pdc_rx[(port)-pdc_rx_idx]
+#define PDC_RX_SWITCH(port)(port)-pdc_rx_idx = !(port)-pdc_rx_idx
+
#ifdef SUPPORT_SYSRQ
static struct console atmel_console;
#endif
+#ifdef SUPPORT_PDC
+static bool atmel_use_dma_rx(struct uart_port *port)
+{
+ struct atmel_uart_port *atmel_port = (struct atmel_uart_port *)port;
+
+ return atmel_port-use_dma_rx;
+}
+
+static bool atmel_use_dma_tx(struct uart_port *port)
+{
+ struct atmel_uart_port *atmel_port = (struct atmel_uart_port *)port;
+
+ return atmel_port-use_dma_tx;
+}
+#else
+static bool atmel_use_dma_rx(struct uart_port *port)
+{
+ return false;
+}
+
+static bool atmel_use_dma_tx(struct uart_port *port)
+{
+ return false;
+}
+#endif
+
/*
* Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty.
*/
@@ -221,7 +272,12 @@ static u_int atmel_get_mctrl(struct uart_port *port)
*/
static void atmel_stop_tx(struct uart_port *port)
{
- UART_PUT_IDR(port, ATMEL_US_TXRDY);
+ if (atmel_use_dma_tx(port)) {
+ /* disable PDC transmit */
+ UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);
+ UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
+ } else
+ UART_PUT_IDR(port, ATMEL_US_TXRDY);
}
/*
@@ -229,7 +285,17 @@ static void atmel_stop_tx(struct uart_port *port)
*/
static void atmel_start_tx(struct uart_port *port)
{
- UART_PUT_IER(port, ATMEL_US_TXRDY);
+ if (atmel_use_dma_tx(port)) {
+ if (UART_GET_PTSR(port) ATMEL_PDC_TXTEN)
+ /* The transmitter is already running. Yes, we
+ really need this.*/
+ return;
+
+ UART_PUT_IER(port, ATMEL_US_ENDTX
Re: [PATCH 5/5] atmel_serial: Add DMA support
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On Tue, 18 Dec 2007, Haavard Skinnemoen wrote: From: Chip Coldwell [EMAIL PROTECTED] This patch is based on the DMA-patch by Chip Coldwell for the AT91/AT32 serial USARTS, with some tweaks to make it apply neatly on top of the other patches in this series. The RX code has been moved to a tasklet and reworked a bit. Instead of depending on the ENDRX and TIMEOUT bits in CSR, we simply grab as much data as we can from the DMA buffers. I think this closes a race where the ENDRX bit is set after we read CSR but before we read RPR, although I haven't confirmed this. This also fixes a DMA sync bug in the original patch. [EMAIL PROTECTED]: rebased onto irq-splitup patch] [EMAIL PROTECTED]: moved to tasklet, fixed dma bug, misc cleanups] Signed-off-by: Remy Bohmer [EMAIL PROTECTED] Signed-off-by: Haavard Skinnemoen [EMAIL PROTECTED] --- drivers/serial/atmel_serial.c | 386 ++-- 1 files changed, 366 insertions(+), 20 deletions(-) diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c index 990d3ab..07c2734 100644 --- a/drivers/serial/atmel_serial.c +++ b/drivers/serial/atmel_serial.c @@ -7,6 +7,8 @@ * Based on drivers/char/serial_sa1100.c, by Deep Blue Solutions Ltd. * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. * + * DMA support added by Chip Coldwell. I will ACK/Sign-off on this soon; I just want to do some tests on real hardware first. Chip - -- Charles M. Coldwell Turn on, log in, tune out Somerville, Massachusetts, New England -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.7 (GNU/Linux) iD8DBQFHaA7cr6maj4UuBS8RAjMSAJsGcKoFKCP/R3aAPhW5hj+v3Qt6ZACgshsF 5NP6/9+NbhDAxBC/7jo8J0Y= =hx4t -END PGP SIGNATURE- -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
