[PATCH v3 0/3] tty: serial: samsung: Serial fixes for Apple A7-A11 SoCs

[PATCH v3 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 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

Nick Chan

---

Nick Chan (3):
  tty: serial: samsung: Use BIT() macro 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: 9aaeb87ce1e966169a57f53a02ba05b30880ffb8
-- 
2.46.0

[PATCH v3 1/3] tty: serial: samsung: Use BIT() macro for APPLE_S5L_*

[Nick Chan]

New entries using BIT() will be added soon, so change the existing ones
for consistency.

Signed-off-by: Nick Chan <towinchenmi@gmail.com>
---
 include/linux/serial_s3c.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/serial_s3c.h b/include/linux/serial_s3c.h
index 1672cf0810ef..1e8686695487 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 | \
@@ -260,9 +260,9 @@
 					 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_RXTHRESH	BIT(4)
+#define APPLE_S5L_UTRSTAT_TXTHRESH	BIT(5)
+#define APPLE_S5L_UTRSTAT_RXTO		BIT(9)
 #define APPLE_S5L_UTRSTAT_ALL_FLAGS	(0x3f0)
 
 #ifndef __ASSEMBLY__
-- 
2.46.0

[PATCH v3 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>
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..7574d4176e76 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

[PATCH v3 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.

Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Nick Chan <towinchenmi@gmail.com>
---
 drivers/tty/serial/samsung_tty.c | 19 +++++++++++++------
 include/linux/serial_s3c.h       | 18 +++++++++++-------
 2 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index 7574d4176e76..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);
 
@@ -2822,7 +2829,7 @@ 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 require MMIO32 register accesses. */
+	/* Apple A7-A11 requires MMIO32 register accesses. */
 	device->port.iotype = UPIO_MEM32;
 
 	/* Close enough to S3C2410 for earlycon... */
diff --git a/include/linux/serial_s3c.h b/include/linux/serial_s3c.h
index 1e8686695487..964a4fbf2626 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	(0x3f0)
+#define APPLE_S5L_UTRSTAT_ALL_FLAGS	(0x3f8)
 
 #ifndef __ASSEMBLY__
 
-- 
2.46.0

Re: [PATCH v3 3/3] tty: serial: samsung: Fix serial rx on Apple A7-A9

[Krzysztof Kozlowski]

On 08/09/2024 11:05, 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.
> 
> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>

This never happened. Please do not add fake tags.

Best regards,
Krzysztof

Re: [PATCH v3 3/3] tty: serial: samsung: Fix serial rx on Apple A7-A9

[Nick Chan]

On 8/9/2024 17:14, Krzysztof Kozlowski wrote:
> On 08/09/2024 11:05, 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.
>>
>> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
> 
> This never happened. Please do not add fake tags.
Sorry, this happened by mistake, and tags are added to both commits present
in previous versions by accident. I can send a v4 tomorrow, though I think
it is the best if this version is to be reviewed, since the mistake does
not make a difference in the patch submitted further upstream, and it saves
everyone's time.

> 
> Best regards,
> Krzysztof
> 

Nick Chan