| Message ID | 20240907111431.2970-2-towinchenmi@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | tty: serial: samsung: Serial fixes for Apple A7-A11 SoCs | expand |
On 07/09/2024 13:06, 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. > > Signed-off-by: Nick Chan <towinchenmi@gmail.com> > --- > drivers/tty/serial/samsung_tty.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c > index c4f2ac9518aa..27b8a50bd3e7 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, > @@ -2825,8 +2825,10 @@ static int __init apple_s5l_early_console_setup(struct earlycon_device *device, > /* Close enough to S3C2410 for earlycon... */ > device->port.private_data = &s3c2410_early_console_data; > > + /* ... however, we need to change the port iotype */ > + device->port.iotype = UPIO_MEM32; If there is going to be resend, then this comment is redundant and can be dropped - repeats the code and does not provide any explanation why. Which would also make the patch smaller and easier to read. See GS101 earlycon. Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Best regards, Krzysztof
On 7/9/2024 20:54, Krzysztof Kozlowski wrote: > On 07/09/2024 13:06, 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. >> >> Signed-off-by: Nick Chan <towinchenmi@gmail.com> >> --- >> drivers/tty/serial/samsung_tty.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c >> index c4f2ac9518aa..27b8a50bd3e7 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, >> @@ -2825,8 +2825,10 @@ static int __init apple_s5l_early_console_setup(struct earlycon_device *device, >> /* Close enough to S3C2410 for earlycon... */ >> device->port.private_data = &s3c2410_early_console_data; >> >> + /* ... however, we need to change the port iotype */ >> + device->port.iotype = UPIO_MEM32; > > If there is going to be resend, then this comment is redundant and can > be dropped - repeats the code and does not provide any explanation why. > > Which would also make the patch smaller and easier to read. See GS101 > earlycon. I agree that the comment is quite useless as-is. However, I think it is worthwhile to mention that A7-A11 expect MMIO32 register accesses here, as someone looking at this code is likely using one of the newer SoCs, which does not have this restriction. > > > > Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> > > Best regards, > Krzysztof > Nick Chan
diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c index c4f2ac9518aa..27b8a50bd3e7 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, @@ -2825,8 +2825,10 @@ static int __init apple_s5l_early_console_setup(struct earlycon_device *device, /* Close enough to S3C2410 for earlycon... */ device->port.private_data = &s3c2410_early_console_data; + /* ... however, we need to change the port iotype */ + device->port.iotype = UPIO_MEM32; #ifdef CONFIG_ARM64 - /* ... but we need to override the existing fixmap entry as nGnRnE */ + /* ... and also override the existing fixmap entry as nGnRnE */ __set_fixmap(FIX_EARLYCON_MEM_BASE, device->port.mapbase, __pgprot(PROT_DEVICE_nGnRnE)); #endif
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. Signed-off-by: Nick Chan <towinchenmi@gmail.com> --- drivers/tty/serial/samsung_tty.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)