* [PATCH] hw/sd/allwinner-sdhost: report FIFO water level as 1 when data ready
@ 2022-05-20 12:42 Icenowy Zheng
2022-05-23 14:14 ` Peter Maydell
0 siblings, 1 reply; 4+ messages in thread
From: Icenowy Zheng @ 2022-05-20 12:42 UTC (permalink / raw)
To: Beniamino Galvani, Peter Maydell, Niek Linnenbank
Cc: qemu-arm, qemu-devel, Icenowy Zheng
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>
---
hw/sd/allwinner-sdhost.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/hw/sd/allwinner-sdhost.c b/hw/sd/allwinner-sdhost.c
index 041e45c680..b66fd9bce7 100644
--- a/hw/sd/allwinner-sdhost.c
+++ b/hw/sd/allwinner-sdhost.c
@@ -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;
--
2.36.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] hw/sd/allwinner-sdhost: report FIFO water level as 1 when data ready
2022-05-20 12:42 [PATCH] hw/sd/allwinner-sdhost: report FIFO water level as 1 when data ready Icenowy Zheng
@ 2022-05-23 14:14 ` Peter Maydell
2022-05-23 16:40 ` Icenowy Zheng
0 siblings, 1 reply; 4+ messages in thread
From: Peter Maydell @ 2022-05-23 14:14 UTC (permalink / raw)
To: Icenowy Zheng; +Cc: Beniamino Galvani, Niek Linnenbank, qemu-arm, qemu-devel
On Fri, 20 May 2022 at 13:42, Icenowy Zheng <uwu@icenowy.me> wrote:
>
> 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>
> ---
> hw/sd/allwinner-sdhost.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/hw/sd/allwinner-sdhost.c b/hw/sd/allwinner-sdhost.c
> index 041e45c680..b66fd9bce7 100644
> --- a/hw/sd/allwinner-sdhost.c
> +++ b/hw/sd/allwinner-sdhost.c
> @@ -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),
> };
Is there documentation on this hardware available somewhere?
The Linux kernel driver for it doesn't seem to have a #define
for this bit 17.
In an ideal world we'd actually emulate the FIFO itself
(our pl181 and bcm2835_sdhost models do this, for example).
-- PMM
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] hw/sd/allwinner-sdhost: report FIFO water level as 1 when data ready
2022-05-23 14:14 ` Peter Maydell
@ 2022-05-23 16:40 ` Icenowy Zheng
2022-05-30 11:36 ` Peter Maydell
0 siblings, 1 reply; 4+ messages in thread
From: Icenowy Zheng @ 2022-05-23 16:40 UTC (permalink / raw)
To: Peter Maydell; +Cc: Beniamino Galvani, Niek Linnenbank, qemu-arm, qemu-devel
在 2022-05-23星期一的 15:14 +0100,Peter Maydell写道:
> On Fri, 20 May 2022 at 13:42, Icenowy Zheng <uwu@icenowy.me> wrote:
> >
> > 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>
> > ---
> > hw/sd/allwinner-sdhost.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/hw/sd/allwinner-sdhost.c b/hw/sd/allwinner-sdhost.c
> > index 041e45c680..b66fd9bce7 100644
> > --- a/hw/sd/allwinner-sdhost.c
> > +++ b/hw/sd/allwinner-sdhost.c
> > @@ -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),
> > };
>
> Is there documentation on this hardware available somewhere?
> The Linux kernel driver for it doesn't seem to have a #define
> for this bit 17.
For the specific version on H3,
https://linux-sunxi.org/File:Allwinner_H3_Datasheet_V1.2.pdf .
>
> In an ideal world we'd actually emulate the FIFO itself
> (our pl181 and bcm2835_sdhost models do this, for example).
Interesting, I will check it.
> -- PMM
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] hw/sd/allwinner-sdhost: report FIFO water level as 1 when data ready
2022-05-23 16:40 ` Icenowy Zheng
@ 2022-05-30 11:36 ` Peter Maydell
0 siblings, 0 replies; 4+ messages in thread
From: Peter Maydell @ 2022-05-30 11:36 UTC (permalink / raw)
To: Icenowy Zheng; +Cc: Beniamino Galvani, Niek Linnenbank, qemu-arm, qemu-devel
On Mon, 23 May 2022 at 17:40, Icenowy Zheng <uwu@icenowy.me> wrote:
>
> 在 2022-05-23星期一的 15:14 +0100,Peter Maydell写道:
> > On Fri, 20 May 2022 at 13:42, Icenowy Zheng <uwu@icenowy.me> wrote:
> > >
> > > 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>
> > > ---
> > > hw/sd/allwinner-sdhost.c | 7 +++++++
> > > 1 file changed, 7 insertions(+)
> > >
> > > diff --git a/hw/sd/allwinner-sdhost.c b/hw/sd/allwinner-sdhost.c
> > > index 041e45c680..b66fd9bce7 100644
> > > --- a/hw/sd/allwinner-sdhost.c
> > > +++ b/hw/sd/allwinner-sdhost.c
> > > @@ -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),
> > > };
> >
> > Is there documentation on this hardware available somewhere?
> > The Linux kernel driver for it doesn't seem to have a #define
> > for this bit 17.
>
> For the specific version on H3,
> https://linux-sunxi.org/File:Allwinner_H3_Datasheet_V1.2.pdf .
Thanks. Since this patch fixes u-boot and is a reasonable
approximation to correct device behaviour assuming we don't
want to bother emulating the FIFO properly, I've applied
it to my target-arm.next tree.
-- PMM
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-05-30 11:56 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-20 12:42 [PATCH] hw/sd/allwinner-sdhost: report FIFO water level as 1 when data ready Icenowy Zheng
2022-05-23 14:14 ` Peter Maydell
2022-05-23 16:40 ` Icenowy Zheng
2022-05-30 11:36 ` Peter Maydell
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.