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SubjectRe: [PATCH] tty: 8250: Add 64byte UART support for FSL platforms
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On Tue, 2014-12-30 at 15:08 +0530, Vijay Rai wrote:
> Some of FSL SoCs like T1040 has new version of UART controller which
> can support 64byte FiFo.
> To enable 64 byte support, following needs to be done:
> -FCR[EN64] needs to be programmed to 1 to enable it.
> -Also, when FCR[EN64]==1, RTL bits to be used as below
> to define various Receive Trigger Levels:
> -FCR[RTL] = 00 1 byte
> -FCR[RTL] = 01 16 bytes
> -FCR[RTL] = 10 32 bytes
> -FCR[RTL] = 11 56 bytes
> -tx_loadsz is set to 32-bytes instead of 64-bytes to implement
> workaround of errata A-008006 which states that tx_loadsz should
> be configured less than Maximum supported fifo bytes

Why 32 and not 63?

> Signed-off-by: Vijay Rai <vijay.rai@freescale.com>
> Signed-off-by: Priyanka Jain <Priyanka.Jain@freescale.com>
> Signed-off-by: Poonam Aggrwal <poonam.aggrwal@freescale.com>
> ---
> drivers/tty/serial/8250/8250_core.c | 20 +++++++++++++++++++-
> include/uapi/linux/serial_core.h | 3 ++-
> include/uapi/linux/serial_reg.h | 3 ++-
> 3 files changed, 23 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
> index 11c6685..565748c 100644
> --- a/drivers/tty/serial/8250/8250_core.c
> +++ b/drivers/tty/serial/8250/8250_core.c
> @@ -329,6 +329,14 @@ static const struct serial8250_config uart_config[] = {
> .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
> .flags = UART_CAP_FIFO | UART_CAP_AFE,
> },
> + [PORT_16550A_FSL64] = {
> + .name = "16550A_FSL64",
> + .fifo_size = 64,
> + .tx_loadsz = 32,

Put a comment here mentioning the erratum.

> diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
> index c172180..a3b4491 100644
> --- a/include/uapi/linux/serial_core.h
> +++ b/include/uapi/linux/serial_core.h
> @@ -55,7 +55,8 @@
> #define PORT_ALTR_16550_F64 27 /* Altera 16550 UART with 64 FIFOs */
> #define PORT_ALTR_16550_F128 28 /* Altera 16550 UART with 128 FIFOs */
> #define PORT_RT2880 29 /* Ralink RT2880 internal UART */
> -#define PORT_MAX_8250 29 /* max port ID */
> +#define PORT_16550A_FSL64 30 /* Freescale 16550 UART with 64 FIFOs */
> +#define PORT_MAX_8250 31 /* max port ID */

Why are you adding 2 to PORT_MAX_8250 when you only add one new type?

-Scott




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