Re: [PATCH 01/26] Revert "serial: uart: add hw flow control support configuration"

2014-09-02 Thread Murali Karicheri 

On 09/02/2014 05:58 PM, Peter Hurley wrote:

On 09/02/2014 05:50 PM, Murali Karicheri wrote:

Peter,

On 09/02/2014 05:39 PM, Peter Hurley wrote:

  Finally, this patch
supposes to fix existing bugs in the serial core for auto CTS-enabled
hardware, but does not include the class of hardware for which these
bugs exist.


What is this? What class of hardware are you referring to?


UART_CAP_AFE and UART_CAP_EFR hardware.


As discussed, I will send an updated patch for this as discussed..


Great.

And since that patch will touch every single line this reverts (and more)
with a different solution, I see no reason not to back this out.



No Issues and I am fine with the revert.


Plus, as you can see, you're holding up progress.


I need to make progress on the hardware that I deal with for which this 
patch was submitted :) Unfortunately this patch didn't get proper review 
before merge causing the issue. Just want to give right context.


Regards,
Murali


Regards,
Peter Hurley



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 01/26] Revert "serial: uart: add hw flow control support configuration"

2014-09-02 Thread Peter Hurley 
On 09/02/2014 05:50 PM, Murali Karicheri wrote:
> Peter,
> 
> On 09/02/2014 05:39 PM, Peter Hurley wrote:
>>  Finally, this patch
>> supposes to fix existing bugs in the serial core for auto CTS-enabled
>> hardware, but does not include the class of hardware for which these
>> bugs exist.
> 
> What is this? What class of hardware are you referring to?

UART_CAP_AFE and UART_CAP_EFR hardware.

> As discussed, I will send an updated patch for this as discussed..

Great.

And since that patch will touch every single line this reverts (and more)
with a different solution, I see no reason not to back this out.

Plus, as you can see, you're holding up progress.

Regards,
Peter Hurley

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 01/26] Revert "serial: uart: add hw flow control support configuration"

2014-09-02 Thread Murali Karicheri 

Peter,

On 09/02/2014 05:39 PM, Peter Hurley wrote:

 Finally, this patch
supposes to fix existing bugs in the serial core for auto CTS-enabled
hardware, but does not include the class of hardware for which these
bugs exist.


What is this? What class of hardware are you referring to?

As discussed, I will send an updated patch for this as discussed..

Regards,

Murali


CC: Murali Karicheri
CC: Rob Herring
Signed-off-by: Peter Hurley
---
  Documentation/devicetree/bindings/serial/of-serial.txt |  1 -
  drivers/tty/serial/8250/8250_core.c|  6 ++
  drivers/tty/serial/of_serial.c |  4 
  drivers/tty/serial/serial_core.c   | 12 +++-
  4 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/Documentation/devicetree/bindings/serial/of-serial.txt 
b/Documentation/devicetree/bindings/serial/of-serial.txt
index 7705477..1928a3e 100644
--- a/Documentation/devicetree/bindings/serial/of-serial.txt
+++ b/Documentation/devicetree/bindings/serial/of-serial.txt
@@ -37,7 +37,6 @@ Optional properties:
  - auto-flow-control: one way to enable automatic flow control support. The
driver is allowed to detect support for the capability even without this
property.
-- has-hw-flow-control: the hardware has flow control capability.

  Example:

diff --git a/drivers/tty/serial/8250/8250_core.c 
b/drivers/tty/serial/8250/8250_core.c
index 7a91c6d..109da60 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -2333,11 +2333,9 @@ serial8250_do_set_termios(struct uart_port *port, struct 
ktermios *termios,
 * the trigger, or the MCR RTS bit is cleared.  In the case where
 * the remote UART is not using CTS auto flow control, we must
 * have sufficient FIFO entries for the latency of the remote
-* UART to respond.  IOW, at least 32 bytes of FIFO. Also enable
-* AFE if hw flow control is supported
+* UART to respond.  IOW, at least 32 bytes of FIFO.
 */
-   if ((up->capabilities&  UART_CAP_AFE&&  (port->fifosize>= 32)) ||
-   (port->flags&  UPF_HARD_FLOW)) {
+   if (up->capabilities&  UART_CAP_AFE&&  port->fifosize>= 32) {
up->mcr&= ~UART_MCR_AFE;
if (termios->c_cflag&  CRTSCTS)
up->mcr |= UART_MCR_AFE;
diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
index 68d4455..27981e2 100644
--- a/drivers/tty/serial/of_serial.c
+++ b/drivers/tty/serial/of_serial.c
@@ -183,10 +183,6 @@ static int of_platform_serial_probe(struct platform_device 
*ofdev)
  "auto-flow-control"))
port8250.capabilities |= UART_CAP_AFE;

-   if (of_property_read_bool(ofdev->dev.of_node,
- "has-hw-flow-control"))
-   port8250.port.flags |= UPF_HARD_FLOW;
-
ret = serial8250_register_8250_port();
break;
}
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index c2f90ec..261e49e 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -174,12 +174,8 @@ static int uart_port_startup(struct tty_struct *tty, 
struct uart_state *state,
if (tty->termios.c_cflag&  CBAUD)
uart_set_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
}
-   /*
-* if hw support flow control without software intervention,
-* then skip the below check
-*/
-   if (tty_port_cts_enabled(port)&&
-   !(uport->flags&  UPF_HARD_FLOW)) {
+
+   if (tty_port_cts_enabled(port)) {
spin_lock_irq(>lock);
if (!(uport->ops->get_mctrl(uport)&  TIOCM_CTS))
tty->hw_stopped = 1;
@@ -2777,9 +2773,7 @@ void uart_handle_cts_change(struct uart_port *uport, 
unsigned int status)

uport->icount.cts++;

-   /* skip below code if the hw flow control is supported */
-   if (tty_port_cts_enabled(port)&&
-   !(uport->flags&  UPF_HARD_FLOW)) {
+   if (tty_port_cts_enabled(port)) {
if (tty->hw_stopped) {
if (status) {
tty->hw_stopped = 0;


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[PATCH 01/26] Revert "serial: uart: add hw flow control support configuration"

2014-09-02 Thread Peter Hurley 
This reverts commit 06aa82e498c144c7784a6f3d3b55458b272d6146.
This commit purports to enable auto CTS flow control for the 8250
UART driver. However, the 8250 UART driver already supports auto
CTS flow control via UART_CAP_AFE and UART_CAP_EFR. Indeed, this
patch introduces another DT attribute for which an existing firmware
flag already exists ("auto-flow-control"). Furthermore, the use of
UPF_HARD_FLOW requires the UART driver to define .throttle and
.unthrottle methods, neither of which are defined for the 8250 UART
driver (which will result in a NULL ptr dereference). Finally, this patch
supposes to fix existing bugs in the serial core for auto CTS-enabled
hardware, but does not include the class of hardware for which these
bugs exist.

CC: Murali Karicheri 
CC: Rob Herring 
Signed-off-by: Peter Hurley 
---
 Documentation/devicetree/bindings/serial/of-serial.txt |  1 -
 drivers/tty/serial/8250/8250_core.c|  6 ++
 drivers/tty/serial/of_serial.c |  4 
 drivers/tty/serial/serial_core.c   | 12 +++-
 4 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/Documentation/devicetree/bindings/serial/of-serial.txt 
b/Documentation/devicetree/bindings/serial/of-serial.txt
index 7705477..1928a3e 100644
--- a/Documentation/devicetree/bindings/serial/of-serial.txt
+++ b/Documentation/devicetree/bindings/serial/of-serial.txt
@@ -37,7 +37,6 @@ Optional properties:
 - auto-flow-control: one way to enable automatic flow control support. The
   driver is allowed to detect support for the capability even without this
   property.
-- has-hw-flow-control: the hardware has flow control capability.
 
 Example:
 
diff --git a/drivers/tty/serial/8250/8250_core.c 
b/drivers/tty/serial/8250/8250_core.c
index 7a91c6d..109da60 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -2333,11 +2333,9 @@ serial8250_do_set_termios(struct uart_port *port, struct 
ktermios *termios,
 * the trigger, or the MCR RTS bit is cleared.  In the case where
 * the remote UART is not using CTS auto flow control, we must
 * have sufficient FIFO entries for the latency of the remote
-* UART to respond.  IOW, at least 32 bytes of FIFO. Also enable
-* AFE if hw flow control is supported
+* UART to respond.  IOW, at least 32 bytes of FIFO.
 */
-   if ((up->capabilities & UART_CAP_AFE && (port->fifosize >= 32)) ||
-   (port->flags & UPF_HARD_FLOW)) {
+   if (up->capabilities & UART_CAP_AFE && port->fifosize >= 32) {
up->mcr &= ~UART_MCR_AFE;
if (termios->c_cflag & CRTSCTS)
up->mcr |= UART_MCR_AFE;
diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
index 68d4455..27981e2 100644
--- a/drivers/tty/serial/of_serial.c
+++ b/drivers/tty/serial/of_serial.c
@@ -183,10 +183,6 @@ static int of_platform_serial_probe(struct platform_device 
*ofdev)
  "auto-flow-control"))
port8250.capabilities |= UART_CAP_AFE;
 
-   if (of_property_read_bool(ofdev->dev.of_node,
- "has-hw-flow-control"))
-   port8250.port.flags |= UPF_HARD_FLOW;
-
ret = serial8250_register_8250_port();
break;
}
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index c2f90ec..261e49e 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -174,12 +174,8 @@ static int uart_port_startup(struct tty_struct *tty, 
struct uart_state *state,
if (tty->termios.c_cflag & CBAUD)
uart_set_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
}
-   /*
-* if hw support flow control without software intervention,
-* then skip the below check
-*/
-   if (tty_port_cts_enabled(port) &&
-   !(uport->flags & UPF_HARD_FLOW)) {
+
+   if (tty_port_cts_enabled(port)) {
spin_lock_irq(>lock);
if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS))
tty->hw_stopped = 1;
@@ -2777,9 +2773,7 @@ void uart_handle_cts_change(struct uart_port *uport, 
unsigned int status)
 
uport->icount.cts++;
 
-   /* skip below code if the hw flow control is supported */
-   if (tty_port_cts_enabled(port) &&
-   !(uport->flags & UPF_HARD_FLOW)) {
+   if (tty_port_cts_enabled(port)) {
if (tty->hw_stopped) {
if (status) {
tty->hw_stopped = 0;
-- 
2.1.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at

[PATCH 01/26] Revert serial: uart: add hw flow control support configuration

2014-09-02 Thread Peter Hurley 
This reverts commit 06aa82e498c144c7784a6f3d3b55458b272d6146.
This commit purports to enable auto CTS flow control for the 8250
UART driver. However, the 8250 UART driver already supports auto
CTS flow control via UART_CAP_AFE and UART_CAP_EFR. Indeed, this
patch introduces another DT attribute for which an existing firmware
flag already exists (auto-flow-control). Furthermore, the use of
UPF_HARD_FLOW requires the UART driver to define .throttle and
.unthrottle methods, neither of which are defined for the 8250 UART
driver (which will result in a NULL ptr dereference). Finally, this patch
supposes to fix existing bugs in the serial core for auto CTS-enabled
hardware, but does not include the class of hardware for which these
bugs exist.

CC: Murali Karicheri m-kariche...@ti.com
CC: Rob Herring robh...@kernel.org
Signed-off-by: Peter Hurley pe...@hurleysoftware.com
---
 Documentation/devicetree/bindings/serial/of-serial.txt |  1 -
 drivers/tty/serial/8250/8250_core.c|  6 ++
 drivers/tty/serial/of_serial.c |  4 
 drivers/tty/serial/serial_core.c   | 12 +++-
 4 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/Documentation/devicetree/bindings/serial/of-serial.txt 
b/Documentation/devicetree/bindings/serial/of-serial.txt
index 7705477..1928a3e 100644
--- a/Documentation/devicetree/bindings/serial/of-serial.txt
+++ b/Documentation/devicetree/bindings/serial/of-serial.txt
@@ -37,7 +37,6 @@ Optional properties:
 - auto-flow-control: one way to enable automatic flow control support. The
   driver is allowed to detect support for the capability even without this
   property.
-- has-hw-flow-control: the hardware has flow control capability.
 
 Example:
 
diff --git a/drivers/tty/serial/8250/8250_core.c 
b/drivers/tty/serial/8250/8250_core.c
index 7a91c6d..109da60 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -2333,11 +2333,9 @@ serial8250_do_set_termios(struct uart_port *port, struct 
ktermios *termios,
 * the trigger, or the MCR RTS bit is cleared.  In the case where
 * the remote UART is not using CTS auto flow control, we must
 * have sufficient FIFO entries for the latency of the remote
-* UART to respond.  IOW, at least 32 bytes of FIFO. Also enable
-* AFE if hw flow control is supported
+* UART to respond.  IOW, at least 32 bytes of FIFO.
 */
-   if ((up-capabilities  UART_CAP_AFE  (port-fifosize = 32)) ||
-   (port-flags  UPF_HARD_FLOW)) {
+   if (up-capabilities  UART_CAP_AFE  port-fifosize = 32) {
up-mcr = ~UART_MCR_AFE;
if (termios-c_cflag  CRTSCTS)
up-mcr |= UART_MCR_AFE;
diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
index 68d4455..27981e2 100644
--- a/drivers/tty/serial/of_serial.c
+++ b/drivers/tty/serial/of_serial.c
@@ -183,10 +183,6 @@ static int of_platform_serial_probe(struct platform_device 
*ofdev)
  auto-flow-control))
port8250.capabilities |= UART_CAP_AFE;
 
-   if (of_property_read_bool(ofdev-dev.of_node,
- has-hw-flow-control))
-   port8250.port.flags |= UPF_HARD_FLOW;
-
ret = serial8250_register_8250_port(port8250);
break;
}
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index c2f90ec..261e49e 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -174,12 +174,8 @@ static int uart_port_startup(struct tty_struct *tty, 
struct uart_state *state,
if (tty-termios.c_cflag  CBAUD)
uart_set_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
}
-   /*
-* if hw support flow control without software intervention,
-* then skip the below check
-*/
-   if (tty_port_cts_enabled(port) 
-   !(uport-flags  UPF_HARD_FLOW)) {
+
+   if (tty_port_cts_enabled(port)) {
spin_lock_irq(uport-lock);
if (!(uport-ops-get_mctrl(uport)  TIOCM_CTS))
tty-hw_stopped = 1;
@@ -2777,9 +2773,7 @@ void uart_handle_cts_change(struct uart_port *uport, 
unsigned int status)
 
uport-icount.cts++;
 
-   /* skip below code if the hw flow control is supported */
-   if (tty_port_cts_enabled(port) 
-   !(uport-flags  UPF_HARD_FLOW)) {
+   if (tty_port_cts_enabled(port)) {
if (tty-hw_stopped) {
if (status) {
tty-hw_stopped = 0;
-- 
2.1.0

--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More

Re: [PATCH 01/26] Revert serial: uart: add hw flow control support configuration

2014-09-02 Thread Murali Karicheri 

Peter,

On 09/02/2014 05:39 PM, Peter Hurley wrote:

 Finally, this patch
supposes to fix existing bugs in the serial core for auto CTS-enabled
hardware, but does not include the class of hardware for which these
bugs exist.


What is this? What class of hardware are you referring to?

As discussed, I will send an updated patch for this as discussed..

Regards,

Murali


CC: Murali Karicherim-kariche...@ti.com
CC: Rob Herringrobh...@kernel.org
Signed-off-by: Peter Hurleype...@hurleysoftware.com
---
  Documentation/devicetree/bindings/serial/of-serial.txt |  1 -
  drivers/tty/serial/8250/8250_core.c|  6 ++
  drivers/tty/serial/of_serial.c |  4 
  drivers/tty/serial/serial_core.c   | 12 +++-
  4 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/Documentation/devicetree/bindings/serial/of-serial.txt 
b/Documentation/devicetree/bindings/serial/of-serial.txt
index 7705477..1928a3e 100644
--- a/Documentation/devicetree/bindings/serial/of-serial.txt
+++ b/Documentation/devicetree/bindings/serial/of-serial.txt
@@ -37,7 +37,6 @@ Optional properties:
  - auto-flow-control: one way to enable automatic flow control support. The
driver is allowed to detect support for the capability even without this
property.
-- has-hw-flow-control: the hardware has flow control capability.

  Example:

diff --git a/drivers/tty/serial/8250/8250_core.c 
b/drivers/tty/serial/8250/8250_core.c
index 7a91c6d..109da60 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -2333,11 +2333,9 @@ serial8250_do_set_termios(struct uart_port *port, struct 
ktermios *termios,
 * the trigger, or the MCR RTS bit is cleared.  In the case where
 * the remote UART is not using CTS auto flow control, we must
 * have sufficient FIFO entries for the latency of the remote
-* UART to respond.  IOW, at least 32 bytes of FIFO. Also enable
-* AFE if hw flow control is supported
+* UART to respond.  IOW, at least 32 bytes of FIFO.
 */
-   if ((up-capabilities  UART_CAP_AFE  (port-fifosize= 32)) ||
-   (port-flags  UPF_HARD_FLOW)) {
+   if (up-capabilities  UART_CAP_AFE  port-fifosize= 32) {
up-mcr= ~UART_MCR_AFE;
if (termios-c_cflag  CRTSCTS)
up-mcr |= UART_MCR_AFE;
diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
index 68d4455..27981e2 100644
--- a/drivers/tty/serial/of_serial.c
+++ b/drivers/tty/serial/of_serial.c
@@ -183,10 +183,6 @@ static int of_platform_serial_probe(struct platform_device 
*ofdev)
  auto-flow-control))
port8250.capabilities |= UART_CAP_AFE;

-   if (of_property_read_bool(ofdev-dev.of_node,
- has-hw-flow-control))
-   port8250.port.flags |= UPF_HARD_FLOW;
-
ret = serial8250_register_8250_port(port8250);
break;
}
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index c2f90ec..261e49e 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -174,12 +174,8 @@ static int uart_port_startup(struct tty_struct *tty, 
struct uart_state *state,
if (tty-termios.c_cflag  CBAUD)
uart_set_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
}
-   /*
-* if hw support flow control without software intervention,
-* then skip the below check
-*/
-   if (tty_port_cts_enabled(port)
-   !(uport-flags  UPF_HARD_FLOW)) {
+
+   if (tty_port_cts_enabled(port)) {
spin_lock_irq(uport-lock);
if (!(uport-ops-get_mctrl(uport)  TIOCM_CTS))
tty-hw_stopped = 1;
@@ -2777,9 +2773,7 @@ void uart_handle_cts_change(struct uart_port *uport, 
unsigned int status)

uport-icount.cts++;

-   /* skip below code if the hw flow control is supported */
-   if (tty_port_cts_enabled(port)
-   !(uport-flags  UPF_HARD_FLOW)) {
+   if (tty_port_cts_enabled(port)) {
if (tty-hw_stopped) {
if (status) {
tty-hw_stopped = 0;


--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 01/26] Revert serial: uart: add hw flow control support configuration

2014-09-02 Thread Peter Hurley 
On 09/02/2014 05:50 PM, Murali Karicheri wrote:
 Peter,
 
 On 09/02/2014 05:39 PM, Peter Hurley wrote:
  Finally, this patch
 supposes to fix existing bugs in the serial core for auto CTS-enabled
 hardware, but does not include the class of hardware for which these
 bugs exist.
 
 What is this? What class of hardware are you referring to?

UART_CAP_AFE and UART_CAP_EFR hardware.

 As discussed, I will send an updated patch for this as discussed..

Great.

And since that patch will touch every single line this reverts (and more)
with a different solution, I see no reason not to back this out.

Plus, as you can see, you're holding up progress.

Regards,
Peter Hurley

--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 01/26] Revert serial: uart: add hw flow control support configuration

2014-09-02 Thread Murali Karicheri 

On 09/02/2014 05:58 PM, Peter Hurley wrote:

On 09/02/2014 05:50 PM, Murali Karicheri wrote:

Peter,

On 09/02/2014 05:39 PM, Peter Hurley wrote:

  Finally, this patch
supposes to fix existing bugs in the serial core for auto CTS-enabled
hardware, but does not include the class of hardware for which these
bugs exist.


What is this? What class of hardware are you referring to?


UART_CAP_AFE and UART_CAP_EFR hardware.


As discussed, I will send an updated patch for this as discussed..


Great.

And since that patch will touch every single line this reverts (and more)
with a different solution, I see no reason not to back this out.



No Issues and I am fine with the revert.


Plus, as you can see, you're holding up progress.


I need to make progress on the hardware that I deal with for which this 
patch was submitted :) Unfortunately this patch didn't get proper review 
before merge causing the issue. Just want to give right context.


Regards,
Murali


Regards,
Peter Hurley



--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/