[PATCH v4 0/2] ns16550-related patches

[PATCH v4 0/2] ns16550-related patches

[Antony Pavlov]

This patch series consist of two ns16550-related patches.

[PATCH v4 1/4] ns16550: support for UART with broken FIFO
[PATCH v4 2/4] ns16550: make ns16550_serial_init_port() shorter
[PATCH v4 3/4] ns16550: write zero to ier only once
[PATCH v4 4/4] ns16550: fix ier selection

The 1st one adds the flag (NS16650_FLAG_DISABLE_FIFO) in internal
ns16550 data structure to recognise UART with broken FIFO
(or UART without FIFO at all) and the code to use this flag.
The flag can be set in board-related code.

The 2nd one use the fact that ns16550_serial_init_port() and
ns16550_setbaudrate() functions have many common code.
It change the most of ns16550_serial_init_port() code for
one ns16550_setbaudrate() call.

The 3rd one removes unnecessary interrupt disable on every
speed change operation.

The 4th one adds explicit IER register selection before accessing it.

_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox

[PATCH v4 1/4] ns16550: support for UART with broken FIFO

[Antony Pavlov]

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
 drivers/serial/serial_ns16550.c |   18 ++++++++++++++++--
 include/ns16550.h               |    2 ++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
index 1217a5f..4cef469 100644
--- a/drivers/serial/serial_ns16550.c
+++ b/drivers/serial/serial_ns16550.c
@@ -139,6 +139,8 @@ static unsigned int ns16550_calc_divisor(struct console_device *cdev,
 static void ns16550_serial_init_port(struct console_device *cdev)
 {
 	unsigned int baud_divisor;
+	struct NS16550_plat *plat = (struct NS16550_plat *)
+	    cdev->dev->platform_data;
 
 	/* Setup the serial port with the defaults first */
 	baud_divisor = ns16550_calc_divisor(cdev, CONFIG_BAUDRATE);
@@ -153,7 +155,12 @@ static void ns16550_serial_init_port(struct console_device *cdev)
 	ns16550_write(cdev, (baud_divisor >> 8) & 0xff, dlm);
 	ns16550_write(cdev, LCRVAL, lcr);
 	ns16550_write(cdev, MCRVAL, mcr);
-	ns16550_write(cdev, FCRVAL, fcr);
+
+	if (plat->flags & NS16650_FLAG_DISABLE_FIFO)
+		ns16550_write(cdev, FCRVAL & ~FCR_FIFO_EN, fcr);
+	else
+		ns16550_write(cdev, FCRVAL, fcr);
+
 #ifdef CONFIG_DRIVER_SERIAL_NS16550_OMAP_EXTENSIONS
 	ns16550_write(cdev, 0x00,  mdr1);
 #endif
@@ -211,6 +218,8 @@ static int ns16550_tstc(struct console_device *cdev)
 static int ns16550_setbaudrate(struct console_device *cdev, int baud_rate)
 {
 	unsigned int baud_divisor = ns16550_calc_divisor(cdev, baud_rate);
+	struct NS16550_plat *plat = (struct NS16550_plat *)
+	    cdev->dev->platform_data;
 
 	ns16550_write(cdev, 0x00, ier);
 	ns16550_write(cdev, LCR_BKSE, lcr);
@@ -218,7 +227,12 @@ static int ns16550_setbaudrate(struct console_device *cdev, int baud_rate)
 	ns16550_write(cdev, (baud_divisor >> 8) & 0xff, dlm);
 	ns16550_write(cdev, LCRVAL, lcr);
 	ns16550_write(cdev, MCRVAL, mcr);
-	ns16550_write(cdev, FCRVAL, fcr);
+
+	if (plat->flags & NS16650_FLAG_DISABLE_FIFO)
+		ns16550_write(cdev, FCRVAL & ~FCR_FIFO_EN, fcr);
+	else
+		ns16550_write(cdev, FCRVAL, fcr);
+
 	return 0;
 }
 
diff --git a/include/ns16550.h b/include/ns16550.h
index 5fd52fa..4a41b93 100644
--- a/include/ns16550.h
+++ b/include/ns16550.h
@@ -52,6 +52,8 @@ struct NS16550_plat {
 				    unsigned char reg_offset);
 
 	int shift;
+	unsigned int flags;
+#define NS16650_FLAG_DISABLE_FIFO	1
 };
 
 #endif				/* __NS16650_PLATFORM_H_ */
-- 
1.7.8.3


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox

[PATCH v4 2/4] ns16550: make ns16550_serial_init_port() shorter

[Antony Pavlov]

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
 drivers/serial/serial_ns16550.c |   20 +++-----------------
 1 files changed, 3 insertions(+), 17 deletions(-)

diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
index 4cef469..3382acd 100644
--- a/drivers/serial/serial_ns16550.c
+++ b/drivers/serial/serial_ns16550.c
@@ -47,6 +47,7 @@
 #include <ns16550.h>
 
 /*********** Private Functions **********************************/
+static int ns16550_setbaudrate(struct console_device *cdev, int baud_rate);
 
 /**
  * @brief read register
@@ -120,7 +121,7 @@ static void ns16550_write(struct console_device *cdev, uint32_t val,
  *
  * @return divisor to be set
  */
-static unsigned int ns16550_calc_divisor(struct console_device *cdev,
+static inline unsigned int ns16550_calc_divisor(struct console_device *cdev,
 					 unsigned int baudrate)
 {
 	struct NS16550_plat *plat = (struct NS16550_plat *)
@@ -138,28 +139,13 @@ static unsigned int ns16550_calc_divisor(struct console_device *cdev,
  */
 static void ns16550_serial_init_port(struct console_device *cdev)
 {
-	unsigned int baud_divisor;
-	struct NS16550_plat *plat = (struct NS16550_plat *)
-	    cdev->dev->platform_data;
-
-	/* Setup the serial port with the defaults first */
-	baud_divisor = ns16550_calc_divisor(cdev, CONFIG_BAUDRATE);
-
 	/* initializing the device for the first time */
 	ns16550_write(cdev, 0x00, ier);
 #ifdef CONFIG_DRIVER_SERIAL_NS16550_OMAP_EXTENSIONS
 	ns16550_write(cdev, 0x07, mdr1);	/* Disable */
 #endif
-	ns16550_write(cdev, LCR_BKSE | LCRVAL, lcr);
-	ns16550_write(cdev, baud_divisor & 0xFF, dll);
-	ns16550_write(cdev, (baud_divisor >> 8) & 0xff, dlm);
-	ns16550_write(cdev, LCRVAL, lcr);
-	ns16550_write(cdev, MCRVAL, mcr);
 
-	if (plat->flags & NS16650_FLAG_DISABLE_FIFO)
-		ns16550_write(cdev, FCRVAL & ~FCR_FIFO_EN, fcr);
-	else
-		ns16550_write(cdev, FCRVAL, fcr);
+	ns16550_setbaudrate(cdev, CONFIG_BAUDRATE);
 
 #ifdef CONFIG_DRIVER_SERIAL_NS16550_OMAP_EXTENSIONS
 	ns16550_write(cdev, 0x00,  mdr1);
-- 
1.7.8.3


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox

[PATCH v4 3/4] ns16550: write zero to ier only once

[Antony Pavlov]

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
 drivers/serial/serial_ns16550.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
index 3382acd..802331d 100644
--- a/drivers/serial/serial_ns16550.c
+++ b/drivers/serial/serial_ns16550.c
@@ -207,7 +207,6 @@ static int ns16550_setbaudrate(struct console_device *cdev, int baud_rate)
 	struct NS16550_plat *plat = (struct NS16550_plat *)
 	    cdev->dev->platform_data;
 
-	ns16550_write(cdev, 0x00, ier);
 	ns16550_write(cdev, LCR_BKSE, lcr);
 	ns16550_write(cdev, baud_divisor & 0xff, dll);
 	ns16550_write(cdev, (baud_divisor >> 8) & 0xff, dlm);
-- 
1.7.8.3


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox

[PATCH v4 4/4] ns16550: fix ier selection

[Antony Pavlov]

The document "PC16550D Universal Asynchronous
Receiver Transmitter with FIFOs" (vers. June 1995,
http://www.national.com/ds/PC/PC16550D.pdf) states
that IER (Interrupt Enable Register) is accessible
if the bit DLAB = 0 (DLAB is bit 7 in LCR; in barebox
DLAB known as LCR_BKSE).

So before IER access we need set DLAB to 0.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
 drivers/serial/serial_ns16550.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
index 802331d..88ba836 100644
--- a/drivers/serial/serial_ns16550.c
+++ b/drivers/serial/serial_ns16550.c
@@ -140,7 +140,9 @@ static inline unsigned int ns16550_calc_divisor(struct console_device *cdev,
 static void ns16550_serial_init_port(struct console_device *cdev)
 {
 	/* initializing the device for the first time */
+	ns16550_write(cdev, 0x00, lcr); /* select ier reg */
 	ns16550_write(cdev, 0x00, ier);
+
 #ifdef CONFIG_DRIVER_SERIAL_NS16550_OMAP_EXTENSIONS
 	ns16550_write(cdev, 0x07, mdr1);	/* Disable */
 #endif
-- 
1.7.8.3


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox