[PATCH v5 0/3] tty: serial: samsung: Serial fixes for Apple A7-A11 SoCs

[PATCH v5 0/3] tty: serial: samsung: Serial fixes for Apple A7-A11 SoCs

[Nick Chan]

Hi,

This series fixes issues with serial on A7-A11 SoCs. The changes do not
seem to affect existing M1 and up users so they can be applied
unconditionally.

Firstly, these SoCs require 32-bit writes on the serial port. This only
manifested in earlycon as reg-io-width in device tree is consulted for
normal serial writes.

Secondly, A7-A9 SoCs seems to use different bits for RXTO and RXTO
enable. Accessing these bits in addition to the original RXTO and RXTO
enable bits will allow serial rx to work correctly on those SoCs.

Changes in v5:
  - Convert existing APPLE_S5L_* entries to use GENMASK() macro in
    addition to BIT(), as suggested by Andi.

Changes in v4:
  - Removed fake Reviewed-by tag added by accident... need to stop
    making stupid mistakes that wastes everyone's time. The remaining
    Reviewed-by is real as far as I am aware.

Changes in v3:
  - v2 did not declare itself as v2 in subject line... resend as v3.

Changes in v2:
  - Mention A7-A11 in the comment about changing register accesses to
    MMIO32.

  - Use BIT() macro for new entries, and change the existing APPLE_S5L_*
    entries for consistency.

v1: https://lore.kernel.org/linux-samsung-soc/20240907111431.2970-1-towinchenmi@gmail.com
v2: https://lore.kernel.org/linux-samsung-soc/20240908075904.12133-1-towinchenmi@gmail.com
v3: https://lore.kernel.org/linux-samsung-soc/20240908090939.2745-1-towinchenmi@gmail.com
v4: https://lore.kernel.org/linux-samsung-soc/20240909084222.3209-1-towinchenmi@gmail.com/

Nick Chan

---
Nick Chan (3):
  tty: serial: samsung: Use bit manipulation macros for APPLE_S5L_*
  tty: serial: samsung: Fix A7-A11 serial earlycon SError
  tty: serial: samsung: Fix serial rx on Apple A7-A9

 drivers/tty/serial/samsung_tty.c | 22 ++++++++++++++++------
 include/linux/serial_s3c.h       | 24 ++++++++++++++----------
 2 files changed, 30 insertions(+), 16 deletions(-)


base-commit: 6708132e80a2ced620bde9b9c36e426183544a23
-- 
2.46.0

[PATCH v5 1/3] tty: serial: samsung: Use bit manipulation macros for APPLE_S5L_*

[Nick Chan]

New entries using BIT() will be added soon, so change the existing ones to
use bit manipulation macros including BIT() and GENMASK() for
consistency.

Suggested-by: Krzysztof Kozlowski <krzk@kernel.org>
Tested-by: Janne Grunau <j@jannau.net>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Nick Chan <towinchenmi@gmail.com>
---
 include/linux/serial_s3c.h | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/serial_s3c.h b/include/linux/serial_s3c.h
index 1672cf0810ef..2a934e20ca4b 100644
--- a/include/linux/serial_s3c.h
+++ b/include/linux/serial_s3c.h
@@ -249,9 +249,9 @@
 #define APPLE_S5L_UCON_RXTO_ENA		9
 #define APPLE_S5L_UCON_RXTHRESH_ENA	12
 #define APPLE_S5L_UCON_TXTHRESH_ENA	13
-#define APPLE_S5L_UCON_RXTO_ENA_MSK	(1 << APPLE_S5L_UCON_RXTO_ENA)
-#define APPLE_S5L_UCON_RXTHRESH_ENA_MSK	(1 << APPLE_S5L_UCON_RXTHRESH_ENA)
-#define APPLE_S5L_UCON_TXTHRESH_ENA_MSK	(1 << APPLE_S5L_UCON_TXTHRESH_ENA)
+#define APPLE_S5L_UCON_RXTO_ENA_MSK	BIT(APPLE_S5L_UCON_RXTO_ENA)
+#define APPLE_S5L_UCON_RXTHRESH_ENA_MSK	BIT(APPLE_S5L_UCON_RXTHRESH_ENA)
+#define APPLE_S5L_UCON_TXTHRESH_ENA_MSK	BIT(APPLE_S5L_UCON_TXTHRESH_ENA)
 
 #define APPLE_S5L_UCON_DEFAULT		(S3C2410_UCON_TXIRQMODE | \
 					 S3C2410_UCON_RXIRQMODE | \
@@ -260,10 +260,10 @@
 					 APPLE_S5L_UCON_RXTHRESH_ENA_MSK | \
 					 APPLE_S5L_UCON_TXTHRESH_ENA_MSK)
 
-#define APPLE_S5L_UTRSTAT_RXTHRESH	(1<<4)
-#define APPLE_S5L_UTRSTAT_TXTHRESH	(1<<5)
-#define APPLE_S5L_UTRSTAT_RXTO		(1<<9)
-#define APPLE_S5L_UTRSTAT_ALL_FLAGS	(0x3f0)
+#define APPLE_S5L_UTRSTAT_RXTHRESH	BIT(4)
+#define APPLE_S5L_UTRSTAT_TXTHRESH	BIT(5)
+#define APPLE_S5L_UTRSTAT_RXTO		BIT(9)
+#define APPLE_S5L_UTRSTAT_ALL_FLAGS	GENMASK(9, 4)
 
 #ifndef __ASSEMBLY__
 
-- 
2.46.0

Re: [PATCH v5 1/3] tty: serial: samsung: Use bit manipulation macros for APPLE_S5L_*

[Andi Shyti]

Hi Nick,

On Wed, Sep 11, 2024 at 01:02:11PM GMT, Nick Chan wrote:
> New entries using BIT() will be added soon, so change the existing ones to
> use bit manipulation macros including BIT() and GENMASK() for
> consistency.
> 
> Suggested-by: Krzysztof Kozlowski <krzk@kernel.org>
> Tested-by: Janne Grunau <j@jannau.net>
> Reviewed-by: Neal Gompa <neal@gompa.dev>
> Signed-off-by: Nick Chan <towinchenmi@gmail.com>

Thanks for the cleanup!

Reviewed-by: Andi Shyti <andi.shyti@kernel.org>

Andi

[PATCH v5 2/3] tty: serial: samsung: Fix A7-A11 serial earlycon SError

[Nick Chan]

Apple's earlier SoCs, like A7-A11, requires 32-bit writes for the serial
port. Otherwise, a SError happens when writing to UTXH (+0x20). This only
manifested in earlycon as reg-io-width in the device tree is consulted
for normal serial writes.

Change the iotype of the port to UPIO_MEM32, to allow the serial port to
function on A7-A11 SoCs. This change does not appear to affect Apple M1 and
above.

Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Tested-by: Janne Grunau <j@jannau.net>
Signed-off-by: Nick Chan <towinchenmi@gmail.com>
---
 drivers/tty/serial/samsung_tty.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index c4f2ac9518aa..3fdec06322ac 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -2536,7 +2536,7 @@ static const struct s3c24xx_serial_drv_data s5l_serial_drv_data = {
 		.name		= "Apple S5L UART",
 		.type		= TYPE_APPLE_S5L,
 		.port_type	= PORT_8250,
-		.iotype		= UPIO_MEM,
+		.iotype		= UPIO_MEM32,
 		.fifosize	= 16,
 		.rx_fifomask	= S3C2410_UFSTAT_RXMASK,
 		.rx_fifoshift	= S3C2410_UFSTAT_RXSHIFT,
@@ -2822,6 +2822,9 @@ OF_EARLYCON_DECLARE(gs101, "google,gs101-uart", gs101_early_console_setup);
 static int __init apple_s5l_early_console_setup(struct earlycon_device *device,
 						const char *opt)
 {
+	/* Apple A7-A11 requires MMIO32 register accesses. */
+	device->port.iotype = UPIO_MEM32;
+
 	/* Close enough to S3C2410 for earlycon... */
 	device->port.private_data = &s3c2410_early_console_data;
 
-- 
2.46.0

Re: [PATCH v5 2/3] tty: serial: samsung: Fix A7-A11 serial earlycon SError

[Andi Shyti]

Hi Nick,

On Wed, Sep 11, 2024 at 01:02:12PM GMT, Nick Chan wrote:
> Apple's earlier SoCs, like A7-A11, requires 32-bit writes for the serial
> port. Otherwise, a SError happens when writing to UTXH (+0x20). This only
> manifested in earlycon as reg-io-width in the device tree is consulted
> for normal serial writes.
> 
> Change the iotype of the port to UPIO_MEM32, to allow the serial port to
> function on A7-A11 SoCs. This change does not appear to affect Apple M1 and
> above.
> 
> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
> Reviewed-by: Neal Gompa <neal@gompa.dev>
> Tested-by: Janne Grunau <j@jannau.net>
> Signed-off-by: Nick Chan <towinchenmi@gmail.com>

Reviewed-by: Andi Shyti <andi.shyti@kernel.org>

Andi

[PATCH v5 3/3] tty: serial: samsung: Fix serial rx on Apple A7-A9

[Nick Chan]

Apple's older A7-A9 SoCs seems to use bit 3 in UTRSTAT as RXTO, which is
enabled by bit 11 in UCON.

Access these bits in addition to the original RXTO and RXTO enable bits,
to allow serial rx to function on A7-A9 SoCs. This change does not
appear to affect the A10 SoC and up.

Tested-by: Janne Grunau <j@jannau.net>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Nick Chan <towinchenmi@gmail.com>
---
 drivers/tty/serial/samsung_tty.c | 17 ++++++++++++-----
 include/linux/serial_s3c.h       | 18 +++++++++++-------
 2 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index 3fdec06322ac..0d184ee2f9ce 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -550,6 +550,7 @@ static void s3c24xx_serial_stop_rx(struct uart_port *port)
 		case TYPE_APPLE_S5L:
 			s3c24xx_clear_bit(port, APPLE_S5L_UCON_RXTHRESH_ENA, S3C2410_UCON);
 			s3c24xx_clear_bit(port, APPLE_S5L_UCON_RXTO_ENA, S3C2410_UCON);
+			s3c24xx_clear_bit(port, APPLE_S5L_UCON_RXTO_LEGACY_ENA, S3C2410_UCON);
 			break;
 		default:
 			disable_irq_nosync(ourport->rx_irq);
@@ -963,9 +964,11 @@ static irqreturn_t apple_serial_handle_irq(int irq, void *id)
 	u32 pend = rd_regl(port, S3C2410_UTRSTAT);
 	irqreturn_t ret = IRQ_NONE;
 
-	if (pend & (APPLE_S5L_UTRSTAT_RXTHRESH | APPLE_S5L_UTRSTAT_RXTO)) {
+	if (pend & (APPLE_S5L_UTRSTAT_RXTHRESH | APPLE_S5L_UTRSTAT_RXTO |
+		APPLE_S5L_UTRSTAT_RXTO_LEGACY)) {
 		wr_regl(port, S3C2410_UTRSTAT,
-			APPLE_S5L_UTRSTAT_RXTHRESH | APPLE_S5L_UTRSTAT_RXTO);
+			APPLE_S5L_UTRSTAT_RXTHRESH | APPLE_S5L_UTRSTAT_RXTO |
+			APPLE_S5L_UTRSTAT_RXTO_LEGACY);
 		ret = s3c24xx_serial_rx_irq(ourport);
 	}
 	if (pend & APPLE_S5L_UTRSTAT_TXTHRESH) {
@@ -1190,7 +1193,8 @@ static void apple_s5l_serial_shutdown(struct uart_port *port)
 	ucon = rd_regl(port, S3C2410_UCON);
 	ucon &= ~(APPLE_S5L_UCON_TXTHRESH_ENA_MSK |
 		  APPLE_S5L_UCON_RXTHRESH_ENA_MSK |
-		  APPLE_S5L_UCON_RXTO_ENA_MSK);
+		  APPLE_S5L_UCON_RXTO_ENA_MSK |
+		  APPLE_S5L_UCON_RXTO_LEGACY_ENA_MSK);
 	wr_regl(port, S3C2410_UCON, ucon);
 
 	wr_regl(port, S3C2410_UTRSTAT, APPLE_S5L_UTRSTAT_ALL_FLAGS);
@@ -1287,6 +1291,7 @@ static int apple_s5l_serial_startup(struct uart_port *port)
 	/* Enable Rx Interrupt */
 	s3c24xx_set_bit(port, APPLE_S5L_UCON_RXTHRESH_ENA, S3C2410_UCON);
 	s3c24xx_set_bit(port, APPLE_S5L_UCON_RXTO_ENA, S3C2410_UCON);
+	s3c24xx_set_bit(port, APPLE_S5L_UCON_RXTO_LEGACY_ENA, S3C2410_UCON);
 
 	return ret;
 }
@@ -2143,13 +2148,15 @@ static int s3c24xx_serial_resume_noirq(struct device *dev)
 
 			ucon &= ~(APPLE_S5L_UCON_TXTHRESH_ENA_MSK |
 				  APPLE_S5L_UCON_RXTHRESH_ENA_MSK |
-				  APPLE_S5L_UCON_RXTO_ENA_MSK);
+				  APPLE_S5L_UCON_RXTO_ENA_MSK |
+				  APPLE_S5L_UCON_RXTO_LEGACY_ENA_MSK);
 
 			if (ourport->tx_enabled)
 				ucon |= APPLE_S5L_UCON_TXTHRESH_ENA_MSK;
 			if (ourport->rx_enabled)
 				ucon |= APPLE_S5L_UCON_RXTHRESH_ENA_MSK |
-					APPLE_S5L_UCON_RXTO_ENA_MSK;
+					APPLE_S5L_UCON_RXTO_ENA_MSK |
+					APPLE_S5L_UCON_RXTO_LEGACY_ENA_MSK;
 
 			wr_regl(port, S3C2410_UCON, ucon);
 
diff --git a/include/linux/serial_s3c.h b/include/linux/serial_s3c.h
index 2a934e20ca4b..102aa33d956c 100644
--- a/include/linux/serial_s3c.h
+++ b/include/linux/serial_s3c.h
@@ -246,24 +246,28 @@
 				 S5PV210_UFCON_TXTRIG4 |	\
 				 S5PV210_UFCON_RXTRIG4)
 
-#define APPLE_S5L_UCON_RXTO_ENA		9
-#define APPLE_S5L_UCON_RXTHRESH_ENA	12
-#define APPLE_S5L_UCON_TXTHRESH_ENA	13
-#define APPLE_S5L_UCON_RXTO_ENA_MSK	BIT(APPLE_S5L_UCON_RXTO_ENA)
-#define APPLE_S5L_UCON_RXTHRESH_ENA_MSK	BIT(APPLE_S5L_UCON_RXTHRESH_ENA)
-#define APPLE_S5L_UCON_TXTHRESH_ENA_MSK	BIT(APPLE_S5L_UCON_TXTHRESH_ENA)
+#define APPLE_S5L_UCON_RXTO_ENA			9
+#define APPLE_S5L_UCON_RXTO_LEGACY_ENA		11
+#define APPLE_S5L_UCON_RXTHRESH_ENA		12
+#define APPLE_S5L_UCON_TXTHRESH_ENA		13
+#define APPLE_S5L_UCON_RXTO_ENA_MSK		BIT(APPLE_S5L_UCON_RXTO_ENA)
+#define APPLE_S5L_UCON_RXTO_LEGACY_ENA_MSK	BIT(APPLE_S5L_UCON_RXTO_LEGACY_ENA)
+#define APPLE_S5L_UCON_RXTHRESH_ENA_MSK		BIT(APPLE_S5L_UCON_RXTHRESH_ENA)
+#define APPLE_S5L_UCON_TXTHRESH_ENA_MSK		BIT(APPLE_S5L_UCON_TXTHRESH_ENA)
 
 #define APPLE_S5L_UCON_DEFAULT		(S3C2410_UCON_TXIRQMODE | \
 					 S3C2410_UCON_RXIRQMODE | \
 					 S3C2410_UCON_RXFIFO_TOI)
 #define APPLE_S5L_UCON_MASK		(APPLE_S5L_UCON_RXTO_ENA_MSK | \
+					 APPLE_S5L_UCON_RXTO_LEGACY_ENA_MSK | \
 					 APPLE_S5L_UCON_RXTHRESH_ENA_MSK | \
 					 APPLE_S5L_UCON_TXTHRESH_ENA_MSK)
 
+#define APPLE_S5L_UTRSTAT_RXTO_LEGACY	BIT(3)
 #define APPLE_S5L_UTRSTAT_RXTHRESH	BIT(4)
 #define APPLE_S5L_UTRSTAT_TXTHRESH	BIT(5)
 #define APPLE_S5L_UTRSTAT_RXTO		BIT(9)
-#define APPLE_S5L_UTRSTAT_ALL_FLAGS	GENMASK(9, 4)
+#define APPLE_S5L_UTRSTAT_ALL_FLAGS	GENMASK(9, 3)
 
 #ifndef __ASSEMBLY__
 
-- 
2.46.0

Re: [PATCH v5 3/3] tty: serial: samsung: Fix serial rx on Apple A7-A9

[Andi Shyti]

Hi Nick,

On Wed, Sep 11, 2024 at 01:02:13PM GMT, Nick Chan wrote:
> Apple's older A7-A9 SoCs seems to use bit 3 in UTRSTAT as RXTO, which is
> enabled by bit 11 in UCON.
> 
> Access these bits in addition to the original RXTO and RXTO enable bits,
> to allow serial rx to function on A7-A9 SoCs. This change does not
> appear to affect the A10 SoC and up.
> 
> Tested-by: Janne Grunau <j@jannau.net>
> Reviewed-by: Neal Gompa <neal@gompa.dev>
> Signed-off-by: Nick Chan <towinchenmi@gmail.com>

Reviewed-by: Andi Shyti <andi.shyti@kernel.org>

Thanks,
Andi