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hw/sd/allwinner-sdhost: report FIFO water level as 1 when data ready

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U-Boot queries the FIFO water level to reduce checking status register
when doing PIO SD card operation.

Report a FIFO water level of 1 when data is ready, to prevent the code
from trying to read 0 words from the FIFO each time.

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Message-id: 20220520124200.2112699-1-uwu@icenowy.me
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Icenowy Zheng 2022-05-20 20:42:00 +08:00 committed by Peter Maydell
parent b5fb359cb5
commit fd71f258bc
1 changed files with 7 additions and 0 deletions
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7
hw/sd/allwinner-sdhost.c
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@ -114,7 +114,9 @@ enum {
};
enum {
SD_STAR_FIFO_EMPTY = (1 << 2),
SD_STAR_CARD_PRESENT = (1 << 8),
SD_STAR_FIFO_LEVEL_1 = (1 << 17),
};
enum {
@ -467,6 +469,11 @@ static uint64_t allwinner_sdhost_read(void *opaque, hwaddr offset,
break;
case REG_SD_STAR: /* Status */
res = s->status;
if (sdbus_data_ready(&s->sdbus)) {
res |= SD_STAR_FIFO_LEVEL_1;
} else {
res |= SD_STAR_FIFO_EMPTY;
}
break;
case REG_SD_FWLR: /* FIFO Water Level */
res = s->fifo_wlevel;