| Message ID | 20220214133710.3278506-3-javierm@redhat.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | drm: Add driver for Solomon SSD130x OLED displays | expand |
On Mon, Feb 14, 2022 at 02:37:06PM +0100, Javier Martinez Canillas wrote: > Add support to convert from XR24 to reversed monochrome for drivers that > control monochromatic display panels, that only have 1 bit per pixel. > > The function does a line-by-line conversion doing an intermediate step > first from XR24 to 8-bit grayscale and then to reversed monochrome. > > The drm_fb_gray8_to_mono_reversed_line() helper was based on code from > drivers/gpu/drm/tiny/repaper.c driver. > > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> > Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Maxime Ripard <maxime@cerno.tech> Maxime
Hi Javier, On Mon, Feb 14, 2022 at 2:37 PM Javier Martinez Canillas <javierm@redhat.com> wrote: > Add support to convert from XR24 to reversed monochrome for drivers that > control monochromatic display panels, that only have 1 bit per pixel. > > The function does a line-by-line conversion doing an intermediate step > first from XR24 to 8-bit grayscale and then to reversed monochrome. > > The drm_fb_gray8_to_mono_reversed_line() helper was based on code from > drivers/gpu/drm/tiny/repaper.c driver. > > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> > Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Thanks for your patch, which is now commit bcf8b616deb87941 ("drm/format-helper: Add drm_fb_xrgb8888_to_mono_reversed()") in drm/drm-next. > --- a/drivers/gpu/drm/drm_format_helper.c > +++ b/drivers/gpu/drm/drm_format_helper.c > @@ -12,9 +12,11 @@ > #include <linux/slab.h> > #include <linux/io.h> > > +#include <drm/drm_device.h> > #include <drm/drm_format_helper.h> > #include <drm/drm_framebuffer.h> > #include <drm/drm_fourcc.h> > +#include <drm/drm_print.h> > #include <drm/drm_rect.h> > > static unsigned int clip_offset(const struct drm_rect *clip, unsigned int pitch, unsigned int cpp) > @@ -591,3 +593,111 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for > return -EINVAL; > } > EXPORT_SYMBOL(drm_fb_blit_toio); > + > +static void drm_fb_gray8_to_mono_reversed_line(u8 *dst, const u8 *src, unsigned int pixels, "pixels" is not the number of pixels to process, but the number of bytes in the monochrome destination buffer. > + unsigned int start_offset, unsigned int end_len) > +{ > + unsigned int xb, i; > + > + for (xb = 0; xb < pixels; xb++) { > + unsigned int start = 0, end = 8; > + u8 byte = 0x00; > + > + if (xb == 0 && start_offset) > + start = start_offset; > + > + if (xb == pixels - 1 && end_len) > + end = end_len; > + > + for (i = start; i < end; i++) { > + unsigned int x = xb * 8 + i; > + > + byte >>= 1; > + if (src[x] >> 7) > + byte |= BIT(7); > + } > + *dst++ = byte; > + } The above is IMHO very hard to read. I think it can be made simpler by passing the total number of pixels to process instead of "pixels" (which is bytes) and "end_len". > +} > + > +/** > + * drm_fb_xrgb8888_to_mono_reversed - Convert XRGB8888 to reversed monochrome > + * @dst: reversed monochrome destination buffer > + * @dst_pitch: Number of bytes between two consecutive scanlines within dst > + * @src: XRGB8888 source buffer > + * @fb: DRM framebuffer > + * @clip: Clip rectangle area to copy > + * > + * DRM doesn't have native monochrome support. > + * Such drivers can announce the commonly supported XR24 format to userspace > + * and use this function to convert to the native format. > + * > + * This function uses drm_fb_xrgb8888_to_gray8() to convert to grayscale and > + * then the result is converted from grayscale to reversed monohrome. > + */ > +void drm_fb_xrgb8888_to_mono_reversed(void *dst, unsigned int dst_pitch, const void *vaddr, > + const struct drm_framebuffer *fb, const struct drm_rect *clip) > +{ > + unsigned int linepixels = drm_rect_width(clip); > + unsigned int lines = clip->y2 - clip->y1; drm_rect_height(clip)? > + unsigned int cpp = fb->format->cpp[0]; > + unsigned int len_src32 = linepixels * cpp; > + struct drm_device *dev = fb->dev; > + unsigned int start_offset, end_len; > + unsigned int y; > + u8 *mono = dst, *gray8; > + u32 *src32; > + > + if (drm_WARN_ON(dev, fb->format->format != DRM_FORMAT_XRGB8888)) > + return; > + > + /* > + * The reversed mono destination buffer contains 1 bit per pixel > + * and destination scanlines have to be in multiple of 8 pixels. > + */ > + if (!dst_pitch) > + dst_pitch = DIV_ROUND_UP(linepixels, 8); This is not correct when clip->x1 is not a multiple of 8 pixels. Should be: DIV_ROUND_UP(linepixels + clip->x1 % 8, 8); > + > + drm_WARN_ONCE(dev, dst_pitch % 8 != 0, "dst_pitch is not a multiple of 8\n"); This triggers for me: dst_pitch = 1. Which is perfectly fine, when flashing an 8-pixel wide cursor ;-) > + > + /* > + * The cma memory is write-combined so reads are uncached. > + * Speed up by fetching one line at a time. > + * > + * Also, format conversion from XR24 to reversed monochrome > + * are done line-by-line but are converted to 8-bit grayscale > + * as an intermediate step. > + * > + * Allocate a buffer to be used for both copying from the cma > + * memory and to store the intermediate grayscale line pixels. > + */ > + src32 = kmalloc(len_src32 + linepixels, GFP_KERNEL); > + if (!src32) > + return; > + > + gray8 = (u8 *)src32 + len_src32; > + > + /* > + * For damage handling, it is possible that only parts of the source > + * buffer is copied and this could lead to start and end pixels that > + * are not aligned to multiple of 8. > + * > + * Calculate if the start and end pixels are not aligned and set the > + * offsets for the reversed mono line conversion function to adjust. > + */ > + start_offset = clip->x1 % 8; > + end_len = clip->x2 % 8; > + > + vaddr += clip_offset(clip, fb->pitches[0], cpp); > + for (y = 0; y < lines; y++) { > + src32 = memcpy(src32, vaddr, len_src32); > + drm_fb_xrgb8888_to_gray8_line(gray8, src32, linepixels); > + drm_fb_gray8_to_mono_reversed_line(mono, gray8, dst_pitch, > + start_offset, end_len); > + vaddr += fb->pitches[0]; > + mono += dst_pitch; > + } > + > + kfree(src32); > +} > +EXPORT_SYMBOL(drm_fb_xrgb8888_to_mono_reversed); Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
Hello Geert, Thanks a lot for your feedback. On 3/8/22 17:13, Geert Uytterhoeven wrote: [snip] >> + >> +static void drm_fb_gray8_to_mono_reversed_line(u8 *dst, const u8 *src, unsigned int pixels, > > "pixels" is not the number of pixels to process, but the number of > bytes in the monochrome destination buffer. > Right, that parameter name is misleading / incorrect indeed. Probably should be changed by dst_pitch or dst_stride. >> + unsigned int start_offset, unsigned int end_len) >> +{ >> + unsigned int xb, i; >> + >> + for (xb = 0; xb < pixels; xb++) { >> + unsigned int start = 0, end = 8; >> + u8 byte = 0x00; >> + >> + if (xb == 0 && start_offset) >> + start = start_offset; >> + >> + if (xb == pixels - 1 && end_len) >> + end = end_len; >> + >> + for (i = start; i < end; i++) { >> + unsigned int x = xb * 8 + i; >> + >> + byte >>= 1; >> + if (src[x] >> 7) >> + byte |= BIT(7); >> + } >> + *dst++ = byte; >> + } > > The above is IMHO very hard to read. > I think it can be made simpler by passing the total number of pixels > to process instead of "pixels" (which is bytes) and "end_len". > Agreed that's hard to read. I think is better if you propose a patch with your idea to make it simpler. [snip] >> +void drm_fb_xrgb8888_to_mono_reversed(void *dst, unsigned int dst_pitch, const void *vaddr, >> + const struct drm_framebuffer *fb, const struct drm_rect *clip) >> +{ >> + unsigned int linepixels = drm_rect_width(clip); >> + unsigned int lines = clip->y2 - clip->y1; > > drm_rect_height(clip)? > Yes, unsure why didn't use it since used drm_rect_width() for the width. >> + unsigned int cpp = fb->format->cpp[0]; >> + unsigned int len_src32 = linepixels * cpp; >> + struct drm_device *dev = fb->dev; >> + unsigned int start_offset, end_len; >> + unsigned int y; >> + u8 *mono = dst, *gray8; >> + u32 *src32; >> + >> + if (drm_WARN_ON(dev, fb->format->format != DRM_FORMAT_XRGB8888)) >> + return; >> + >> + /* >> + * The reversed mono destination buffer contains 1 bit per pixel >> + * and destination scanlines have to be in multiple of 8 pixels. >> + */ >> + if (!dst_pitch) >> + dst_pitch = DIV_ROUND_UP(linepixels, 8); > > This is not correct when clip->x1 is not a multiple of 8 pixels. > Should be: > > DIV_ROUND_UP(linepixels + clip->x1 % 8, 8); > Agreed. >> + >> + drm_WARN_ONCE(dev, dst_pitch % 8 != 0, "dst_pitch is not a multiple of 8\n"); > > This triggers for me: dst_pitch = 1. > Which is perfectly fine, when flashing an 8-pixel wide cursor ;-) > Indeed. I think we should just drop that warn. Do you want me to post patches for all these or would you do it when simplifying the drm_fb_gray8_to_mono_reversed_line() logic ?
diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c index b981712623d3..bc0f49773868 100644 --- a/drivers/gpu/drm/drm_format_helper.c +++ b/drivers/gpu/drm/drm_format_helper.c @@ -12,9 +12,11 @@ #include <linux/slab.h> #include <linux/io.h> +#include <drm/drm_device.h> #include <drm/drm_format_helper.h> #include <drm/drm_framebuffer.h> #include <drm/drm_fourcc.h> +#include <drm/drm_print.h> #include <drm/drm_rect.h> static unsigned int clip_offset(const struct drm_rect *clip, unsigned int pitch, unsigned int cpp) @@ -591,3 +593,111 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for return -EINVAL; } EXPORT_SYMBOL(drm_fb_blit_toio); + +static void drm_fb_gray8_to_mono_reversed_line(u8 *dst, const u8 *src, unsigned int pixels, + unsigned int start_offset, unsigned int end_len) +{ + unsigned int xb, i; + + for (xb = 0; xb < pixels; xb++) { + unsigned int start = 0, end = 8; + u8 byte = 0x00; + + if (xb == 0 && start_offset) + start = start_offset; + + if (xb == pixels - 1 && end_len) + end = end_len; + + for (i = start; i < end; i++) { + unsigned int x = xb * 8 + i; + + byte >>= 1; + if (src[x] >> 7) + byte |= BIT(7); + } + *dst++ = byte; + } +} + +/** + * drm_fb_xrgb8888_to_mono_reversed - Convert XRGB8888 to reversed monochrome + * @dst: reversed monochrome destination buffer + * @dst_pitch: Number of bytes between two consecutive scanlines within dst + * @src: XRGB8888 source buffer + * @fb: DRM framebuffer + * @clip: Clip rectangle area to copy + * + * DRM doesn't have native monochrome support. + * Such drivers can announce the commonly supported XR24 format to userspace + * and use this function to convert to the native format. + * + * This function uses drm_fb_xrgb8888_to_gray8() to convert to grayscale and + * then the result is converted from grayscale to reversed monohrome. + */ +void drm_fb_xrgb8888_to_mono_reversed(void *dst, unsigned int dst_pitch, const void *vaddr, + const struct drm_framebuffer *fb, const struct drm_rect *clip) +{ + unsigned int linepixels = drm_rect_width(clip); + unsigned int lines = clip->y2 - clip->y1; + unsigned int cpp = fb->format->cpp[0]; + unsigned int len_src32 = linepixels * cpp; + struct drm_device *dev = fb->dev; + unsigned int start_offset, end_len; + unsigned int y; + u8 *mono = dst, *gray8; + u32 *src32; + + if (drm_WARN_ON(dev, fb->format->format != DRM_FORMAT_XRGB8888)) + return; + + /* + * The reversed mono destination buffer contains 1 bit per pixel + * and destination scanlines have to be in multiple of 8 pixels. + */ + if (!dst_pitch) + dst_pitch = DIV_ROUND_UP(linepixels, 8); + + drm_WARN_ONCE(dev, dst_pitch % 8 != 0, "dst_pitch is not a multiple of 8\n"); + + /* + * The cma memory is write-combined so reads are uncached. + * Speed up by fetching one line at a time. + * + * Also, format conversion from XR24 to reversed monochrome + * are done line-by-line but are converted to 8-bit grayscale + * as an intermediate step. + * + * Allocate a buffer to be used for both copying from the cma + * memory and to store the intermediate grayscale line pixels. + */ + src32 = kmalloc(len_src32 + linepixels, GFP_KERNEL); + if (!src32) + return; + + gray8 = (u8 *)src32 + len_src32; + + /* + * For damage handling, it is possible that only parts of the source + * buffer is copied and this could lead to start and end pixels that + * are not aligned to multiple of 8. + * + * Calculate if the start and end pixels are not aligned and set the + * offsets for the reversed mono line conversion function to adjust. + */ + start_offset = clip->x1 % 8; + end_len = clip->x2 % 8; + + vaddr += clip_offset(clip, fb->pitches[0], cpp); + for (y = 0; y < lines; y++) { + src32 = memcpy(src32, vaddr, len_src32); + drm_fb_xrgb8888_to_gray8_line(gray8, src32, linepixels); + drm_fb_gray8_to_mono_reversed_line(mono, gray8, dst_pitch, + start_offset, end_len); + vaddr += fb->pitches[0]; + mono += dst_pitch; + } + + kfree(src32); +} +EXPORT_SYMBOL(drm_fb_xrgb8888_to_mono_reversed); diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h index b30ed5de0a33..0b0937c0b2f6 100644 --- a/include/drm/drm_format_helper.h +++ b/include/drm/drm_format_helper.h @@ -43,4 +43,8 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for const void *vmap, const struct drm_framebuffer *fb, const struct drm_rect *rect); +void drm_fb_xrgb8888_to_mono_reversed(void *dst, unsigned int dst_pitch, const void *src, + const struct drm_framebuffer *fb, + const struct drm_rect *clip); + #endif /* __LINUX_DRM_FORMAT_HELPER_H */