tty: serial: msm: Add mask value for UART_DM registers
Subsystems (2)
PATCH v2 1/2 tty: serial: msm: Add mask value for UART_DM registers
The bit masks for RFR_LEVEL1 and STALE_TIMEOUT_MSB values in MR1 and IPR registers respectively are different for UART and UART_DM hardware cores. We have been using UART core mask values for these. Add the same for UART_DM core.
There is no bit setting as UART_IPR_RXSTALE_LAST for UART_DM core so do it only for UART core.
---
Changes since last version:
- Added new macro fo UART_DM_MR1_AUTO_RFR_LEVEL1 instead of modifying existing.
- Added a new macro for IPR register as it is also different in UART_DM
- Changed subject line
- Removed change log from message
drivers/tty/serial/msm_serial.c | 19 +++++++++++++++---- drivers/tty/serial/msm_serial.h | 2 ++ 2 files changed, 17 insertions(+), 4 deletions(-)
drivers/tty/serial/msm_serial.c +15 -4
@@ -432,8 +432,13 @@ static int msm_set_baud_rate(struct uart_port *port, unsigned int baud)/* RX stale watermark */ rxstale = entry->rxstale; watermark =UART_IPR_STALE_LSB & rxstale; - watermark |=UART_IPR_RXSTALE_LAST ; - watermark |=UART_IPR_STALE_TIMEOUT_MSB & (rxstale <<2 ); +if (msm_port->is_uartdm) + watermark |=UART_DM_IPR_STALE_TIMEOUT_MSB & (rxstale <<2 ); +else { + watermark |=UART_IPR_RXSTALE_LAST ; + watermark |=UART_IPR_STALE_TIMEOUT_MSB & (rxstale <<2 ); + } +msm_write (port, watermark,UART_IPR );/* set RX watermark */
@@ -496,9 +501,15 @@ static int msm_startup(struct uart_port *port)/* set automatic RFR level */ data =msm_read (port,UART_MR1 ); - data &= ~UART_MR1_AUTO_RFR_LEVEL1 ; +if (msm_port->is_uartdm) { + data &= ~UART_DM_MR1_AUTO_RFR_LEVEL1 ; + data |=UART_DM_MR1_AUTO_RFR_LEVEL1 & (rfr_level <<2 ); + }else { + data &= ~UART_MR1_AUTO_RFR_LEVEL1 ; + data |=UART_MR1_AUTO_RFR_LEVEL1 & (rfr_level <<2 ); + } + data &= ~UART_MR1_AUTO_RFR_LEVEL0 ; - data |=UART_MR1_AUTO_RFR_LEVEL1 & (rfr_level <<2 ); data |=UART_MR1_AUTO_RFR_LEVEL0 & rfr_level;msm_write (port, data,UART_MR1 );return 0 ;
drivers/tty/serial/msm_serial.h +2 -0
@@ -20,6 +20,7 @@#define UART_MR1_AUTO_RFR_LEVEL0 0x3F#define UART_MR1_AUTO_RFR_LEVEL1 0x3FF00 +#define UART_DM_MR1_AUTO_RFR_LEVEL1 0xFFFFFF00#define UART_MR1_RX_RDY_CTL (1 << 7)#define UART_MR1_CTS_CTL (1 << 6)
@@ -78,6 +79,7 @@#define UART_IPR_RXSTALE_LAST 0x20#define UART_IPR_STALE_LSB 0x1F#define UART_IPR_STALE_TIMEOUT_MSB 0x3FF80 +#define UART_DM_IPR_STALE_TIMEOUT_MSB 0xFFFFFF80#define UART_IPR 0x0018#define UART_TFWR 0x001C
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PATCH v2 2/2 tty: serial: msm: Disable pclk when port is closed
Disable the pclk when tty port is closed by user space.
--- drivers/tty/serial/msm_serial.c | 1 + 1 file changed, 1 insertion(+)
drivers/tty/serial/msm_serial.c +1 -0
@@ -523,6 +523,7 @@ static void msm_shutdown(struct uart_port *port)msm_write (port,0 ,UART_IMR );/* disable interrupts */ clk_disable_unprepare (msm_port->clk); +clk_disable_unprepare (msm_port->pclk);free_irq (port->irq, port); }
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Re: [PATCH v2 2/2] tty: serial: msm: Disable pclk when port is closed
Quoted 12 lines · Pramod Gurav
Disable the pclk when tty port is closed by user space.
Signed-off-by Pramod Gurav <[email protected]>--- drivers/tty/serial/msm_serial.c | 1 + 1 file changed, 1 insertion(+)drivers/tty/serial/msm_serial.c +0
-0
drivers/tty/serial/msm_serial.c static void msm_shutdown(struct uart_port *port) · line 529
Quoted 7 lines
drivers/tty/serial/msm_serial.c +1
-0@@ -523,6 +523,7 @@ static void msm_shutdown(struct uart_port *port)msm_write (port,0 ,UART_IMR );/* disable interrupts */ clk_disable_unprepare (msm_port->clk); +clk_disable_unprepare (msm_port->pclk);free_irq (port->irq, port); }
It's not clear to me at all when this clock is enabled and when it's disabled during the lifetime of this driver. For example, why do we have a .pm op to turn clocks on and off? Shouldn't they already be on? Can you please explain when the clocks are turned on and off and what userspace actions cause that to happen? Looking at drivers like amba-pl010.c I don't see any .pm op, just a clk_prepare_enable/clk_disable_unprepare pair in the startup and shutdown ops.
Minus my confusion of why our clocking is complicated, it looks correct to me to do this, so
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Re: [PATCH v2 2/2] tty: serial: msm: Disable pclk when port is closed
Quoted 19 lines · Stephen Boyd
Quoted 18 lines · Pramod Gurav
Disable the pclk when tty port is closed by user space.
Signed-off-by Pramod Gurav <[email protected]>--- drivers/tty/serial/msm_serial.c | 1 + 1 file changed, 1 insertion(+)drivers/tty/serial/msm_serial.c +1
-0@@ -523,6 +523,7 @@ static void msm_shutdown(struct uart_port *port)msm_write (port,0 ,UART_IMR );/* disable interrupts */ clk_disable_unprepare (msm_port->clk); +clk_disable_unprepare (msm_port->pclk);
Quoted 11 lines
drivers/tty/serial/msm_serial.c static void msm_shutdown(struct uart_port *port) · line 529
Quoted 2 lines
drivers/tty/serial/msm_serial.c +0
-0free_irq (port->irq, port); }It's not clear to me at all when this clock is enabled and when it's disabled during the lifetime of this driver. For example, why do we have a .pm op to turn clocks on and off? Shouldn't they already be on? Can you please explain when the clocks are turned on and off and what userspace actions cause that to happen? Looking at drivers like
amba-pl010.cI don't see any .pm op, just a clk_prepare_enable/clk_disable_unprepare pair in the startup and shutdown ops.
When a userspce opens a serial port the uart_startup (in serial_core) function is executed which changes the uart_pm state to UART_PM_STATE_ON. So when this port is release/closed by the application uart_close(serial_core) changes the uart_pm state to UART_PM_STATE_OFF if its not console. But it is not done in uart_shutdown function.
So ideally clk_prepare_enable/clk_disable_unprepare must be called in .pm only. So, we can get rid of these operations from msm_startup function as these will be called anyway using .pm ops.
About .pm in uart_ops, there are few drivers which have it for an example, atmel_serial, sh-sci etc. That is where they do clk_prepare_enable/clk_disable_unprepare. And moreover when there is suspend across system these function will handled through .pm.
Quoted 4 lines
Minus my confusion of why our clocking is complicated, it looks correct to me to do this, so
Quoted 8 lines
Reviewed-by Stephen Boyd <[email protected]>--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
Pramod
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Re: [PATCH v2 2/2] tty: serial: msm: Disable pclk when port is closed
Quoted 19 lines · Pramod Gurav
Quoted 9 lines · Stephen Boyd
It's not clear to me at all when this clock is enabled and when it's disabled during the lifetime of this driver. For example, why do we have a .pm op to turn clocks on and off? Shouldn't they already be on? Can you please explain when the clocks are turned on and off and what userspace actions cause that to happen? Looking at drivers like
amba-pl010.cI don't see any .pm op, just a clk_prepare_enable/clk_disable_unprepare pair in the startup and shutdown ops.When a userspce opens a serial port the
uart_startup(inserial_core) function is executed which changes theuart_pmstate toUART_PM_STATE_ON. So when this port is release/closed by the applicationuart_close(serial_core)changes theuart_pmstate toUART_PM_STATE_OFFif its not console. But it is not done inuart_shutdownfunction.
Quoted 8 lines
So ideally clk_prepare_enable/clk_disable_unprepare must be called in .pm only. So, we can get rid of these operations from
msm_startupfunction as these will be called anyway using .pm ops.About .pm in
uart_ops, there are few drivers which have it for an example,atmel_serial, sh-sci etc. That is where they do clk_prepare_enable/clk_disable_unprepare. And moreover when there is suspend across system these function will handled through .pm.
Ok. If the .pm op is called at the right time then it seems to be possible to drop the clock operations from startup/shutdown. Do other drivers hook the .pm op to do runtime PM as well? Because it would be nice to move this driver to use runtime PM sometime in the future as well.
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Quoted 9 lines · Pramod Gurav
drivers/tty/serial/msm_serial.c +0
-1@@ -432,8 +432,13 @@ static int msm_set_baud_rate(struct uart_port *port, unsigned int baud)/* RX stale watermark */ rxstale = entry->rxstale; watermark =UART_IPR_STALE_LSB & rxstale; - watermark |=UART_IPR_RXSTALE_LAST ;
drivers/tty/serial/msm_serial.c static int msm_set_baud_rate(struct uart_port *port, unsigned int baud) · line 443
Quoted 10 lines
drivers/tty/serial/msm_serial.c +7
-1- watermark |=UART_IPR_STALE_TIMEOUT_MSB & (rxstale <<2 ); +if (msm_port->is_uartdm) + watermark |=UART_DM_IPR_STALE_TIMEOUT_MSB & (rxstale <<2 ); +else { + watermark |=UART_IPR_RXSTALE_LAST ; + watermark |=UART_IPR_STALE_TIMEOUT_MSB & (rxstale <<2 ); + } +msm_write (port, watermark,UART_IPR );
This could be written like so:
if (msm_port->is_uartdm) {
mask = UART_DM_IPR_STALE_TIMEOUT_MSB;
} else {
watermark |= UART_IPR_RXSTALE_LAST;
mask = UART_IPR_STALE_TIMEOUT_MSB;
}watermark |= mask & (rxstale << 2);
so that we don't duplicate the rfr_level << 2 part.
Quoted 9 lines
drivers/tty/serial/msm_serial.c +3
-1/* set RX watermark */ @@ -496,9 +501,15 @@ static int msm_startup(struct uart_port *port)/* set automatic RFR level */ data =msm_read (port,UART_MR1 ); - data &= ~UART_MR1_AUTO_RFR_LEVEL1 ; +if (msm_port->is_uartdm) { + data &= ~UART_DM_MR1_AUTO_RFR_LEVEL1 ; + data |=UART_DM_MR1_AUTO_RFR_LEVEL1 & (rfr_level <<2 );
drivers/tty/serial/msm_serial.c static int msm_startup(struct uart_port *port) · line 515
Quoted 10 lines
drivers/tty/serial/msm_serial.c +5
-1+ }else { + data &= ~UART_MR1_AUTO_RFR_LEVEL1 ; + data |=UART_MR1_AUTO_RFR_LEVEL1 & (rfr_level <<2 ); + } + data &= ~UART_MR1_AUTO_RFR_LEVEL0 ; - data |=UART_MR1_AUTO_RFR_LEVEL1 & (rfr_level <<2 ); data |=UART_MR1_AUTO_RFR_LEVEL0 & rfr_level;msm_write (port, data,UART_MR1 );return 0 ;
This could be written like so:
if (msm_port->is_uartdm)
mask = UART_DM_MR1_AUTO_RFR_LEVEL1; else mask = UART_MR1_AUTO_RFR_LEVE1;
data &= ~mask;
data &= ~UART_MR1_AUTO_RFR_LEVEL0;
data |= mask & (rfr_level << 2);
data |= UART_MR1_AUTO_RFR_LEVEL0 & rfr_level;
so that we don't duplicate the rfr_level << 2 part.
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