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Re: [Qemu-devel] [PATCH v2 07/14] sm501: Fix device endianness
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH v2 07/14] sm501: Fix device endianness |
Date: |
Thu, 2 Mar 2017 21:04:18 +0000 |
On 25 February 2017 at 18:46, BALATON Zoltan <address@hidden> wrote:
> Signed-off-by: BALATON Zoltan <address@hidden>
> ---
>
> v2: Split off small clean up to other patch
>
> hw/display/sm501.c | 6 +++---
> hw/display/sm501_template.h | 23 ++++++++++++++---------
> 2 files changed, 17 insertions(+), 12 deletions(-)
>
> diff --git a/hw/display/sm501.c b/hw/display/sm501.c
> index b977094..2694081 100644
> --- a/hw/display/sm501.c
> +++ b/hw/display/sm501.c
> @@ -849,7 +849,7 @@ static const MemoryRegionOps sm501_system_config_ops = {
> .min_access_size = 4,
> .max_access_size = 4,
> },
> - .endianness = DEVICE_NATIVE_ENDIAN,
> + .endianness = DEVICE_LITTLE_ENDIAN,
> };
>
> static uint32_t sm501_palette_read(void *opaque, hwaddr addr)
> @@ -1085,7 +1085,7 @@ static const MemoryRegionOps sm501_disp_ctrl_ops = {
> .min_access_size = 4,
> .max_access_size = 4,
> },
> - .endianness = DEVICE_NATIVE_ENDIAN,
> + .endianness = DEVICE_LITTLE_ENDIAN,
> };
>
> static uint64_t sm501_2d_engine_read(void *opaque, hwaddr addr,
> @@ -1173,7 +1173,7 @@ static const MemoryRegionOps sm501_2d_engine_ops = {
> .min_access_size = 4,
> .max_access_size = 4,
> },
> - .endianness = DEVICE_NATIVE_ENDIAN,
> + .endianness = DEVICE_LITTLE_ENDIAN,
> };
>
> /* draw line functions for all console modes */
> diff --git a/hw/display/sm501_template.h b/hw/display/sm501_template.h
> index 832ee61..6e56baf 100644
> --- a/hw/display/sm501_template.h
> +++ b/hw/display/sm501_template.h
> @@ -64,10 +64,16 @@ static void glue(draw_line16_, PIXEL_NAME)(
> uint8_t r, g, b;
>
> do {
> - rgb565 = lduw_p(s);
> - r = ((rgb565 >> 11) & 0x1f) << 3;
> - g = ((rgb565 >> 5) & 0x3f) << 2;
> - b = ((rgb565 >> 0) & 0x1f) << 3;
> + rgb565 = lduw_le_p(s);
> +#if defined(TARGET_WORDS_BIGENDIAN)
> + r = (rgb565 >> 8) & 0xf8;
> + g = (rgb565 >> 3) & 0xfc;
> + b = (rgb565 << 3) & 0xf8;
> +#else
> + b = (rgb565 >> 8) & 0xf8;
> + g = (rgb565 >> 3) & 0xfc;
> + r = (rgb565 << 3) & 0xf8;
> +#endif
> *(PIXEL_TYPE *)d = glue(rgb_to_pixel, PIXEL_NAME)(r, g, b);
> s += 2;
> d += BPP;
> @@ -80,15 +86,14 @@ static void glue(draw_line32_, PIXEL_NAME)(
> uint8_t r, g, b;
>
> do {
> - ldub_p(s);
> #if defined(TARGET_WORDS_BIGENDIAN)
> + r = s[0];
> + g = s[1];
> + b = s[2];
> +#else
> r = s[1];
> g = s[2];
> b = s[3];
> -#else
> - b = s[0];
> - g = s[1];
> - r = s[2];
> #endif
> *(PIXEL_TYPE *)d = glue(rgb_to_pixel, PIXEL_NAME)(r, g, b);
> s += 4;
I still suspect this is not correct. In particular, if you
look at the Linux driver:
http://lxr.free-electrons.com/source/drivers/video/fbdev/sm501fb.c#L341
we have for 32 bit two layouts within a 32-bit word:
BGRX (if "swap fb endian" is set)
XRGB (the usual)
(plus the cross-product with "32-bit load is BE or LE",
since we've coded this as byte accesses rather than a ldl_*_p()).
and for 16 bit we have either RGB or BGR ordering.
I'm not completely sure this lines up with the code you have.
Looking at how the SWAP_FB_ENDIAN flag gets set:
* for the r2d board it is set always
* for PCI devices, it is set only if big-endian
I suspect that what we actually have here is something
like:
* for the PCI device it's always little endian (and the
code ought not to need to depend on TARGET_WORDS_BIGENDIAN)
* sysbus device may be more complicated
Also I note there's an SM501_ENDIAN_CONTROL register on the
device, which presumably if written changes the behaviour.
Plus for the sysbus device if we change the settings to
DEVICE_LITTLE_ENDIAN for the various control register
regions that suggests we should be consistent about the
serial_mm_init() endian order and also the USB controller.
It's late evening here though so I can't investigate any
further right now.
thanks
-- PMM
- Re: [Qemu-devel] [PATCH v2 07/14] sm501: Fix device endianness,
Peter Maydell <=
- Re: [Qemu-devel] [PATCH v2 07/14] sm501: Fix device endianness, BALATON Zoltan, 2017/03/02
- Re: [Qemu-devel] [PATCH v2 07/14] sm501: Fix device endianness, Peter Maydell, 2017/03/03
- Re: [Qemu-devel] [PATCH v2 07/14] sm501: Fix device endianness, BALATON Zoltan, 2017/03/03
- Re: [Qemu-devel] [PATCH v2 07/14] sm501: Fix device endianness, Peter Maydell, 2017/03/04
- Re: [Qemu-devel] [PATCH v2 07/14] sm501: Fix device endianness, BALATON Zoltan, 2017/03/04
- Re: [Qemu-devel] [PATCH v2 07/14] sm501: Fix device endianness, Peter Maydell, 2017/03/06
- Re: [Qemu-devel] [PATCH v2 07/14] sm501: Fix device endianness, BALATON Zoltan, 2017/03/06