Re: [PATCH] xen/arm: debug-pl011.inc: Use macros instead of hardcoded values

[Julien Grall <julien@xxxxxxx>]

Hi Michal,

On 24/10/2022 11:05, Michal Orzel wrote:
> Make use of the macros defined in asm/pl011-uart.h instead of hardcoding
> the values. Also, take the opportunity to fix the file extension in a
> top-level comment.
>
> No functional change intended.
>
> Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>
With one comment below:

Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

> ---
>   xen/arch/arm/arm64/debug-pl011.inc | 20 +++++++++++---------
>   1 file changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/xen/arch/arm/arm64/debug-pl011.inc 
> b/xen/arch/arm/arm64/debug-pl011.inc
> index 1928a2e3ffbb..d82f2f1de197 100644
> --- a/xen/arch/arm/arm64/debug-pl011.inc
> +++ b/xen/arch/arm/arm64/debug-pl011.inc
> @@ -1,5 +1,5 @@
>   /*
> - * xen/arch/arm/arm64/debug-pl011.S
> + * xen/arch/arm/arm64/debug-pl011.inc
>    *
>    * PL011 specific debug code
>    *
> @@ -16,6 +16,8 @@
>    * GNU General Public License for more details.
>    */
>   
> + #include <asm/pl011-uart.h>
> +
>   /*
>    * PL011 UART initialization
>    * xb: register which containts the UART base address
> @@ -23,13 +25,13 @@
>    */
>   .macro early_uart_init xb, c
>           mov   x\c, #(7372800 / CONFIG_EARLY_UART_PL011_BAUD_RATE % 16)
> -        strh  w\c, [\xb, #0x28]      /* -> UARTFBRD (Baud divisor fraction) */
> +        strh  w\c, [\xb, #FBRD]      /* -> UARTFBRD (Baud divisor fraction) */
>           mov   x\c, #(7372800 / CONFIG_EARLY_UART_PL011_BAUD_RATE / 16)
> -        strh  w\c, [\xb, #0x24]      /* -> UARTIBRD (Baud divisor integer) */
> +        strh  w\c, [\xb, #IBRD]      /* -> UARTIBRD (Baud divisor integer) */
>           mov   x\c, #0x60             /* 8n1 */
Can we introduce macro/define for 0x60?

> -        str   w\c, [\xb, #0x2C]      /* -> UARTLCR_H (Line control) */
> -        ldr   x\c, =0x00000301       /* RXE | TXE | UARTEN */
> -        str   w\c, [\xb, #0x30]      /* -> UARTCR (Control Register) */
> +        str   w\c, [\xb, #LCR_H]     /* -> UARTLCR_H (Line control) */
> +        ldr   x\c, =(RXE | TXE | UARTEN)
> +        str   w\c, [\xb, #CR]        /* -> UARTCR (Control Register) */
>   .endm
Cheers,

--
Julien Grall