Re: [PATCH 2/2] tty: pl011: Work around QDF2400 E44 for earlycon

2017-02-14 Thread Christopher Covington 
On 02/07/2017 11:31 PM, Shanker Donthineni wrote:
> Hi Cov,
> 
> The same PL011 driver will be used in virtutal machine, make sure
> your changes have no side effects in VM.

Fundamentally, this is the same workaround as has been tested in the qserver
downstream kernel for over a year.

Cheers,
Cov

-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code
Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH 2/2] tty: pl011: Work around QDF2400 E44 for earlycon

2017-02-14 Thread Christopher Covington 
On 02/07/2017 11:31 PM, Shanker Donthineni wrote:
> Hi Cov,
> 
> The same PL011 driver will be used in virtutal machine, make sure
> your changes have no side effects in VM.

Fundamentally, this is the same workaround as has been tested in the qserver
downstream kernel for over a year.

Cheers,
Cov

-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code
Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH 2/2] tty: pl011: Work around QDF2400 E44 for earlycon

2017-02-07 Thread Shanker Donthineni 

Hi Cov,

The same PL011 driver will be used in virtutal machine, make sure your 
changes have no side effects in VM.




On 02/07/2017 10:07 PM, Timur Tabi wrote:

Christopher Covington wrote:

The previous change worked around QDF2432v1 and QDF2400v1 SoC erratum 44
for the full-fledged console, when UART AMBA Port (UAP) data is 
available.
Additionally provide a workaround the earlycon case, again checking 
TXFE ==

0 instead of BUSY == 1. As earlycon is operating before UAP data is
available, the implementation is different than in the preceding patch.

Signed-off-by: Christopher Covington 
---
  drivers/tty/serial/amba-pl011.c | 28 +++-
  1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/amba-pl011.c 
b/drivers/tty/serial/amba-pl011.c

index 41e51901d6ef..f25e7c994f8e 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2411,6 +2411,29 @@ static bool qdf2400_e44(void) {
  cpu_var_model == MIDR_QCOM_FALKOR_V1);
  }
  +#ifdef CONFIG_QCOM_QDF2400_ERRATUM_44
+static void qdf2400_e44_putc(struct uart_port *port, int c)
+{
+while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
+cpu_relax();
+if (port->iotype == UPIO_MEM32)
+writel(c, port->membase + UART01x_DR);
+else
+writeb(c, port->membase + UART01x_DR);
I believe 32-bit writes are safe on QDF2400v1, so I think you 
technically don't need the UPIO_MEM32 check.  Just always call writel.

+while (!(readl(port->membase + UART01x_FR) & UART011_FR_TXFE))
+cpu_relax();
+}
+
+static void qdf2400_e44_early_write(struct console *con, const char 
*s, unsigned n)

+{
+struct earlycon_device *dev = con->data;
+
+uart_console_write(>port, s, n, qdf2400_e44_putc);
+}
+#else
+#define qdf2400_e44_early_write pl011_early_write
+#endif
Same with patch 1/2.  If you change qdf2400_e44(), you don't need the 
#else block.

+
  static void pl011_putc(struct uart_port *port, int c)
  {
  while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
@@ -2436,7 +2459,10 @@ static int __init 
pl011_early_console_setup(struct earlycon_device *device,

  if (!device->port.membase)
  return -ENODEV;
  -device->con->write = pl011_early_write;
+if (qdf2400_e44())
+device->con->write = qdf2400_e44_early_write;
+else
+device->con->write = pl011_early_write;
  return 0;
  }
  OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup);





--
Shanker Donthineni
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm 
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux 
Foundation Collaborative Project.

Re: [PATCH 2/2] tty: pl011: Work around QDF2400 E44 for earlycon

2017-02-07 Thread Shanker Donthineni 

Hi Cov,

The same PL011 driver will be used in virtutal machine, make sure your 
changes have no side effects in VM.




On 02/07/2017 10:07 PM, Timur Tabi wrote:

Christopher Covington wrote:

The previous change worked around QDF2432v1 and QDF2400v1 SoC erratum 44
for the full-fledged console, when UART AMBA Port (UAP) data is 
available.
Additionally provide a workaround the earlycon case, again checking 
TXFE ==

0 instead of BUSY == 1. As earlycon is operating before UAP data is
available, the implementation is different than in the preceding patch.

Signed-off-by: Christopher Covington 
---
  drivers/tty/serial/amba-pl011.c | 28 +++-
  1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/amba-pl011.c 
b/drivers/tty/serial/amba-pl011.c

index 41e51901d6ef..f25e7c994f8e 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2411,6 +2411,29 @@ static bool qdf2400_e44(void) {
  cpu_var_model == MIDR_QCOM_FALKOR_V1);
  }
  +#ifdef CONFIG_QCOM_QDF2400_ERRATUM_44
+static void qdf2400_e44_putc(struct uart_port *port, int c)
+{
+while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
+cpu_relax();
+if (port->iotype == UPIO_MEM32)
+writel(c, port->membase + UART01x_DR);
+else
+writeb(c, port->membase + UART01x_DR);
I believe 32-bit writes are safe on QDF2400v1, so I think you 
technically don't need the UPIO_MEM32 check.  Just always call writel.

+while (!(readl(port->membase + UART01x_FR) & UART011_FR_TXFE))
+cpu_relax();
+}
+
+static void qdf2400_e44_early_write(struct console *con, const char 
*s, unsigned n)

+{
+struct earlycon_device *dev = con->data;
+
+uart_console_write(>port, s, n, qdf2400_e44_putc);
+}
+#else
+#define qdf2400_e44_early_write pl011_early_write
+#endif
Same with patch 1/2.  If you change qdf2400_e44(), you don't need the 
#else block.

+
  static void pl011_putc(struct uart_port *port, int c)
  {
  while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
@@ -2436,7 +2459,10 @@ static int __init 
pl011_early_console_setup(struct earlycon_device *device,

  if (!device->port.membase)
  return -ENODEV;
  -device->con->write = pl011_early_write;
+if (qdf2400_e44())
+device->con->write = qdf2400_e44_early_write;
+else
+device->con->write = pl011_early_write;
  return 0;
  }
  OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup);





--
Shanker Donthineni
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm 
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux 
Foundation Collaborative Project.

Re: [PATCH 2/2] tty: pl011: Work around QDF2400 E44 for earlycon

2017-02-07 Thread Timur Tabi 

Christopher Covington wrote:

The previous change worked around QDF2432v1 and QDF2400v1 SoC erratum 44
for the full-fledged console, when UART AMBA Port (UAP) data is available.
Additionally provide a workaround the earlycon case, again checking TXFE ==
0 instead of BUSY == 1. As earlycon is operating before UAP data is
available, the implementation is different than in the preceding patch.

Signed-off-by: Christopher Covington 
---
  drivers/tty/serial/amba-pl011.c | 28 +++-
  1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 41e51901d6ef..f25e7c994f8e 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2411,6 +2411,29 @@ static bool qdf2400_e44(void) {
cpu_var_model == MIDR_QCOM_FALKOR_V1);
  }
  
+#ifdef CONFIG_QCOM_QDF2400_ERRATUM_44

+static void qdf2400_e44_putc(struct uart_port *port, int c)
+{
+   while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
+   cpu_relax();
+   if (port->iotype == UPIO_MEM32)
+   writel(c, port->membase + UART01x_DR);
+   else
+   writeb(c, port->membase + UART01x_DR);
I believe 32-bit writes are safe on QDF2400v1, so I think you technically don't 
need the UPIO_MEM32 check.  Just always call writel.

+   while (!(readl(port->membase + UART01x_FR) & UART011_FR_TXFE))
+   cpu_relax();
+}
+
+static void qdf2400_e44_early_write(struct console *con, const char *s, 
unsigned n)
+{
+   struct earlycon_device *dev = con->data;
+
+   uart_console_write(>port, s, n, qdf2400_e44_putc);
+}
+#else
+#define qdf2400_e44_early_write pl011_early_write
+#endif

Same with patch 1/2.  If you change qdf2400_e44(), you don't need the #else 
block.

+
  static void pl011_putc(struct uart_port *port, int c)
  {
while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
@@ -2436,7 +2459,10 @@ static int __init pl011_early_console_setup(struct 
earlycon_device *device,
if (!device->port.membase)
return -ENODEV;
  
-	device->con->write = pl011_early_write;

+   if (qdf2400_e44())
+   device->con->write = qdf2400_e44_early_write;
+   else
+   device->con->write = pl011_early_write;
return 0;
  }
  OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup);



--
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the
Code Aurora Forum, hosted by The Linux Foundation.

Re: [PATCH 2/2] tty: pl011: Work around QDF2400 E44 for earlycon

2017-02-07 Thread Timur Tabi 

Christopher Covington wrote:

The previous change worked around QDF2432v1 and QDF2400v1 SoC erratum 44
for the full-fledged console, when UART AMBA Port (UAP) data is available.
Additionally provide a workaround the earlycon case, again checking TXFE ==
0 instead of BUSY == 1. As earlycon is operating before UAP data is
available, the implementation is different than in the preceding patch.

Signed-off-by: Christopher Covington 
---
  drivers/tty/serial/amba-pl011.c | 28 +++-
  1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 41e51901d6ef..f25e7c994f8e 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2411,6 +2411,29 @@ static bool qdf2400_e44(void) {
cpu_var_model == MIDR_QCOM_FALKOR_V1);
  }
  
+#ifdef CONFIG_QCOM_QDF2400_ERRATUM_44

+static void qdf2400_e44_putc(struct uart_port *port, int c)
+{
+   while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
+   cpu_relax();
+   if (port->iotype == UPIO_MEM32)
+   writel(c, port->membase + UART01x_DR);
+   else
+   writeb(c, port->membase + UART01x_DR);
I believe 32-bit writes are safe on QDF2400v1, so I think you technically don't 
need the UPIO_MEM32 check.  Just always call writel.

+   while (!(readl(port->membase + UART01x_FR) & UART011_FR_TXFE))
+   cpu_relax();
+}
+
+static void qdf2400_e44_early_write(struct console *con, const char *s, 
unsigned n)
+{
+   struct earlycon_device *dev = con->data;
+
+   uart_console_write(>port, s, n, qdf2400_e44_putc);
+}
+#else
+#define qdf2400_e44_early_write pl011_early_write
+#endif

Same with patch 1/2.  If you change qdf2400_e44(), you don't need the #else 
block.

+
  static void pl011_putc(struct uart_port *port, int c)
  {
while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
@@ -2436,7 +2459,10 @@ static int __init pl011_early_console_setup(struct 
earlycon_device *device,
if (!device->port.membase)
return -ENODEV;
  
-	device->con->write = pl011_early_write;

+   if (qdf2400_e44())
+   device->con->write = qdf2400_e44_early_write;
+   else
+   device->con->write = pl011_early_write;
return 0;
  }
  OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup);



--
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the
Code Aurora Forum, hosted by The Linux Foundation.

[PATCH 2/2] tty: pl011: Work around QDF2400 E44 for earlycon

2017-02-07 Thread Christopher Covington 
The previous change worked around QDF2432v1 and QDF2400v1 SoC erratum 44
for the full-fledged console, when UART AMBA Port (UAP) data is available.
Additionally provide a workaround the earlycon case, again checking TXFE ==
0 instead of BUSY == 1. As earlycon is operating before UAP data is
available, the implementation is different than in the preceding patch.

Signed-off-by: Christopher Covington 
---
 drivers/tty/serial/amba-pl011.c | 28 +++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 41e51901d6ef..f25e7c994f8e 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2411,6 +2411,29 @@ static bool qdf2400_e44(void) {
cpu_var_model == MIDR_QCOM_FALKOR_V1);
 }
 
+#ifdef CONFIG_QCOM_QDF2400_ERRATUM_44
+static void qdf2400_e44_putc(struct uart_port *port, int c)
+{
+   while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
+   cpu_relax();
+   if (port->iotype == UPIO_MEM32)
+   writel(c, port->membase + UART01x_DR);
+   else
+   writeb(c, port->membase + UART01x_DR);
+   while (!(readl(port->membase + UART01x_FR) & UART011_FR_TXFE))
+   cpu_relax();
+}
+
+static void qdf2400_e44_early_write(struct console *con, const char *s, 
unsigned n)
+{
+   struct earlycon_device *dev = con->data;
+
+   uart_console_write(>port, s, n, qdf2400_e44_putc);
+}
+#else
+#define qdf2400_e44_early_write pl011_early_write
+#endif
+
 static void pl011_putc(struct uart_port *port, int c)
 {
while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
@@ -2436,7 +2459,10 @@ static int __init pl011_early_console_setup(struct 
earlycon_device *device,
if (!device->port.membase)
return -ENODEV;
 
-   device->con->write = pl011_early_write;
+   if (qdf2400_e44())
+   device->con->write = qdf2400_e44_early_write;
+   else
+   device->con->write = pl011_early_write;
return 0;
 }
 OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup);
-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora
Forum, a Linux Foundation Collaborative Project.

[PATCH 2/2] tty: pl011: Work around QDF2400 E44 for earlycon

2017-02-07 Thread Christopher Covington 
The previous change worked around QDF2432v1 and QDF2400v1 SoC erratum 44
for the full-fledged console, when UART AMBA Port (UAP) data is available.
Additionally provide a workaround the earlycon case, again checking TXFE ==
0 instead of BUSY == 1. As earlycon is operating before UAP data is
available, the implementation is different than in the preceding patch.

Signed-off-by: Christopher Covington 
---
 drivers/tty/serial/amba-pl011.c | 28 +++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 41e51901d6ef..f25e7c994f8e 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2411,6 +2411,29 @@ static bool qdf2400_e44(void) {
cpu_var_model == MIDR_QCOM_FALKOR_V1);
 }
 
+#ifdef CONFIG_QCOM_QDF2400_ERRATUM_44
+static void qdf2400_e44_putc(struct uart_port *port, int c)
+{
+   while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
+   cpu_relax();
+   if (port->iotype == UPIO_MEM32)
+   writel(c, port->membase + UART01x_DR);
+   else
+   writeb(c, port->membase + UART01x_DR);
+   while (!(readl(port->membase + UART01x_FR) & UART011_FR_TXFE))
+   cpu_relax();
+}
+
+static void qdf2400_e44_early_write(struct console *con, const char *s, 
unsigned n)
+{
+   struct earlycon_device *dev = con->data;
+
+   uart_console_write(>port, s, n, qdf2400_e44_putc);
+}
+#else
+#define qdf2400_e44_early_write pl011_early_write
+#endif
+
 static void pl011_putc(struct uart_port *port, int c)
 {
while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
@@ -2436,7 +2459,10 @@ static int __init pl011_early_console_setup(struct 
earlycon_device *device,
if (!device->port.membase)
return -ENODEV;
 
-   device->con->write = pl011_early_write;
+   if (qdf2400_e44())
+   device->con->write = qdf2400_e44_early_write;
+   else
+   device->con->write = pl011_early_write;
return 0;
 }
 OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup);
-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora
Forum, a Linux Foundation Collaborative Project.