Re: [PATCH 2/2] tty/serial: at91: add a fallback option to determine uart/usart property

Nicolas Ferre
2013-10-15T09:19:23Z

On 14/10/2013 15:59, Jean-Christophe PLAGNIOL-VILLARD :
> On 10:43 Thu 10 Oct , Nicolas Ferre wrote:
>> On older SoC, the "name" field is not filled in the register map.
>> Fix the way to figure out if the serial port is an uart or an usart for these
>> older products (with corresponding properties).
>>
>> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
>> ---
>> drivers/tty/serial/atmel_serial.c | 19 ++++++++++++++++++-
>> include/linux/atmel_serial.h | 1 +
>> 2 files changed, 19 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
>> index 6b0f75e..c7d99af 100644
>> --- a/drivers/tty/serial/atmel_serial.c
>> +++ b/drivers/tty/serial/atmel_serial.c
>> @@ -99,6 +99,7 @@ static void atmel_stop_rx(struct uart_port *port);
>> #define UART_PUT_RTOR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_RTOR)
>> #define UART_PUT_TTGR(port, v) __raw_writel(v, (port)->membase + ATMEL_US_TTGR)
>> #define UART_GET_IP_NAME(port) __raw_readl((port)->membase + ATMEL_US_NAME)
>> +#define UART_GET_IP_VERSION(port) __raw_readl((port)->membase + ATMEL_US_VERSION)
>>
>> /* PDC registers */
>> #define UART_PUT_PTCR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_PTCR)
>> @@ -1503,6 +1504,7 @@ static void atmel_get_ip_name(struct uart_port *port)
>> {
>> struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
>> int name = UART_GET_IP_NAME(port);
>> + u32 version;
>> int usart, uart;
>> /* usart and uart ascii */
>> usart = 0x55534152;
>> @@ -1517,7 +1519,22 @@ static void atmel_get_ip_name(struct uart_port *port)
>> dev_dbg(port->dev, "This is uart\n");
>> atmel_port->is_usart = false;
>> } else {
>> - dev_err(port->dev, "Not supported ip name, set to uart\n");
>> + /* fallback for older SoCs: use version field */
>> + version = UART_GET_IP_VERSION(port);
>> + switch (version) {
>> + case 0x302:
>> + case 0x10213:
>> + dev_dbg(port->dev, "This version is usart\n");
>> + atmel_port->is_usart = true;
>> + break;
>> + case 0x203:
>> + case 0x10202:
>> + dev_dbg(port->dev, "This version is uart\n");
>> + atmel_port->is_usart = false;
>> + break;
>> + default:
>> + dev_err(port->dev, "Not supported ip name nor version, set to uart\n");
>
> it's not really an error a dev_warn is more oppropriate

As we are already in -rc5 and that these fixes are critical for at91
platforms, I will not re-spin another patch just for this.

Moreover, I have the feeling that if we end up in this case, it means
that we are in big troubles because the usart/uart included in the
product triggering this log is not known (I recall that newer products
do not have to hit these lines of code).

With these 2 reasons, I prefer to keep my patch like it is.

Greg, can you consider taking these two patches as regression fixes for
3.12 (with Tested-by tag from Thomas)?

Thanks, bye,

>> + }
>> }
>> }
>>
>> diff --git a/include/linux/atmel_serial.h b/include/linux/atmel_serial.h
>> index be201ca..00beddf 100644
>> --- a/include/linux/atmel_serial.h
>> +++ b/include/linux/atmel_serial.h
>> @@ -125,5 +125,6 @@
>> #define ATMEL_US_IF 0x4c /* IrDA Filter Register */
>>
>> #define ATMEL_US_NAME 0xf0 /* Ip Name */
>> +#define ATMEL_US_VERSION 0xfc /* Ip Version */
>>
>> #endif
>> --
>> 1.8.2.2
>>
>
>

--
Nicolas Ferre