Re: [PATCH v3 01/14] dp8393x: Mask EOL bit from descriptor addresses

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Hi Finn,

On 1/19/20 11:59 PM, Finn Thain wrote:
> The Least Significant bit of a descriptor address register is used as
> an EOL flag. It has to be masked when the register value is to be used
> as an actual address for copying memory around. But when the registers
> are to be updated the EOL bit should not be masked.
> 
> Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
> Tested-by: Laurent Vivier <laurent@vivier.eu>
> ---
> Changed since v1:
>   - Added macros to name constants as requested by Philippe Mathieu-Daudé.
> ---
>   hw/net/dp8393x.c | 19 ++++++++++++-------
>   1 file changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/net/dp8393x.c b/hw/net/dp8393x.c
> index cdc2631c0c..14901c1445 100644
> --- a/hw/net/dp8393x.c
> +++ b/hw/net/dp8393x.c
> @@ -145,6 +145,9 @@ do { printf("sonic ERROR: %s: " fmt, __func__ , ## __VA_ARGS__); } while (0)
>   #define SONIC_ISR_PINT   0x0800
>   #define SONIC_ISR_LCD    0x1000
>   
> +#define SONIC_DESC_EOL   0x0001
> +#define SONIC_DESC_ADDR  0xFFFE

I'd rather not add SONIC_DESC_ADDR and use ~SONIC_DESC_EOL instead.

Please consider it if you respin the series.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> +
>   #define TYPE_DP8393X "dp8393x"
>   #define DP8393X(obj) OBJECT_CHECK(dp8393xState, (obj), TYPE_DP8393X)
>   
> @@ -197,7 +200,8 @@ static uint32_t dp8393x_crba(dp8393xState *s)
>   
>   static uint32_t dp8393x_crda(dp8393xState *s)
>   {
> -    return (s->regs[SONIC_URDA] << 16) | s->regs[SONIC_CRDA];
> +    return (s->regs[SONIC_URDA] << 16) |
> +           (s->regs[SONIC_CRDA] & SONIC_DESC_ADDR);
>   }
>   
>   static uint32_t dp8393x_rbwc(dp8393xState *s)
> @@ -217,7 +221,8 @@ static uint32_t dp8393x_tsa(dp8393xState *s)
>   
>   static uint32_t dp8393x_ttda(dp8393xState *s)
>   {
> -    return (s->regs[SONIC_UTDA] << 16) | s->regs[SONIC_TTDA];
> +    return (s->regs[SONIC_UTDA] << 16) |
> +           (s->regs[SONIC_TTDA] & SONIC_DESC_ADDR);
>   }
>   
>   static uint32_t dp8393x_wt(dp8393xState *s)
> @@ -506,8 +511,8 @@ static void dp8393x_do_transmit_packets(dp8393xState *s)
>                                sizeof(uint16_t) *
>                                (4 + 3 * s->regs[SONIC_TFC]) * width,
>                   MEMTXATTRS_UNSPECIFIED, (uint8_t *)s->data, size, 0);
> -            s->regs[SONIC_CTDA] = dp8393x_get(s, width, 0) & ~0x1;
> -            if (dp8393x_get(s, width, 0) & 0x1) {
> +            s->regs[SONIC_CTDA] = dp8393x_get(s, width, 0);
> +            if (s->regs[SONIC_CTDA] & SONIC_DESC_EOL) {
>                   /* EOL detected */
>                   break;
>               }
> @@ -763,13 +768,13 @@ static ssize_t dp8393x_receive(NetClientState *nc, const uint8_t * buf,
>       /* XXX: Check byte ordering */
>   
>       /* Check for EOL */
> -    if (s->regs[SONIC_LLFA] & 0x1) {
> +    if (s->regs[SONIC_LLFA] & SONIC_DESC_EOL) {
>           /* Are we still in resource exhaustion? */
>           size = sizeof(uint16_t) * 1 * width;
>           address = dp8393x_crda(s) + sizeof(uint16_t) * 5 * width;
>           address_space_rw(&s->as, address, MEMTXATTRS_UNSPECIFIED,
>                            (uint8_t *)s->data, size, 0);
> -        if (dp8393x_get(s, width, 0) & 0x1) {
> +        if (dp8393x_get(s, width, 0) & SONIC_DESC_EOL) {
>               /* Still EOL ; stop reception */
>               return -1;
>           } else {
> @@ -827,7 +832,7 @@ static ssize_t dp8393x_receive(NetClientState *nc, const uint8_t * buf,
>       address_space_rw(&s->as, dp8393x_crda(s) + sizeof(uint16_t) * 5 * width,
>           MEMTXATTRS_UNSPECIFIED, (uint8_t *)s->data, size, 0);
>       s->regs[SONIC_LLFA] = dp8393x_get(s, width, 0);
> -    if (s->regs[SONIC_LLFA] & 0x1) {
> +    if (s->regs[SONIC_LLFA] & SONIC_DESC_EOL) {
>           /* EOL detected */
>           s->regs[SONIC_ISR] |= SONIC_ISR_RDE;
>       } else {
>