Re: [Xen-devel] [PATCH V9 2/3] drivers/pl011: Use combination of UARTRIS and UARTMSC instead of UARTMIS

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 9 Jun 2016, Shanker Donthineni wrote:
> The Masked interrupt status register (UARTMIS) is not described in ARM
> SBSA 2.x document. Anding of two registers UARTMSC and UARTRIS values
> gives the same information as register UARTMIS.
> 
> UARTRIS, UARTMSC and UARTMIS definitions are found in PrimeCell UART
> PL011 (Revision: r1p4).
>  - 3.3.10 Interrupt mask set/clear register, UARTIMSC
>  - 3.3.11 Raw interrupt status register, UARTRIS
>  - 3.3.12 Masked interrupt status register, UARTMIS
> 
> This change is necessary for driver to be SBSA compliant v2.x without
> affecting the current driver functionality.
> 
> Signed-off-by: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx>
> Reviewed-by: Julien Grall <julien.grall@xxxxxxx>
>
> Changes since v8:
>  Fixed white spaces.
> 
> Changes since v7:
>  Moved comment 'To compatible with SBSA v2.x document, all accesses should be 
> 32-bit' to #3
> 
> Changes since v1:
>  Added a new function to return an interrupt status.
> 
>  xen/drivers/char/pl011.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/drivers/char/pl011.c b/xen/drivers/char/pl011.c
> index 6a3c21b..7e19c4a 100644
> --- a/xen/drivers/char/pl011.c
> +++ b/xen/drivers/char/pl011.c
> @@ -53,11 +53,17 @@ static struct pl011 {
>  #define pl011_read(uart, off)           readl((uart)->regs + (off))
>  #define pl011_write(uart, off,val)      writel((val), (uart)->regs + (off))
>  
> +static unsigned int pl011_intr_status(struct pl011 *uart)

Maybe this should be static inline?

In any case the series is good, I am happy to queue it up for 4.8.


> +{
> +    /* UARTMIS is not documented in SBSA v2.x, so use UARTRIS/UARTIMSC. */
> +    return (pl011_read(uart, RIS) & pl011_read(uart, IMSC));
> +}
> +
>  static void pl011_interrupt(int irq, void *data, struct cpu_user_regs *regs)
>  {
>      struct serial_port *port = data;
>      struct pl011 *uart = port->uart;
> -    unsigned int status = pl011_read(uart, MIS);
> +    unsigned int status = pl011_intr_status(uart);
>  
>      if ( status )
>      {
> @@ -76,7 +82,7 @@ static void pl011_interrupt(int irq, void *data, struct 
> cpu_user_regs *regs)
>              if ( status & (TXI) )
>                  serial_tx_interrupt(port, regs);
>  
> -            status = pl011_read(uart, MIS);
> +            status = pl011_intr_status(uart);
>          } while (status != 0);
>      }
>  }
> -- 
> Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc. 
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, 
> a Linux Foundation Collaborative Project
> 

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