| From 91ba11fb7d7ca0a3bbe8a512e65e666e2ec1e889 Mon Sep 17 00:00:00 2001 |
| From: Mikulas Patocka <mpatocka@redhat.com> |
| Date: Sun, 3 Jun 2018 16:41:00 +0200 |
| Subject: udl-kms: avoid division |
| |
| From: Mikulas Patocka <mpatocka@redhat.com> |
| |
| commit 91ba11fb7d7ca0a3bbe8a512e65e666e2ec1e889 upstream. |
| |
| Division is slow, so it shouldn't be done by the pixel generating code. |
| The driver supports only 2 or 4 bytes per pixel, so we can replace |
| division with a shift. |
| |
| Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> |
| Cc: stable@vger.kernel.org |
| Signed-off-by: Dave Airlie <airlied@redhat.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/gpu/drm/udl/udl_drv.h | 2 - |
| drivers/gpu/drm/udl/udl_fb.c | 15 ++++++++------ |
| drivers/gpu/drm/udl/udl_transfer.c | 39 ++++++++++++++++++------------------- |
| 3 files changed, 30 insertions(+), 26 deletions(-) |
| |
| --- a/drivers/gpu/drm/udl/udl_drv.h |
| +++ b/drivers/gpu/drm/udl/udl_drv.h |
| @@ -110,7 +110,7 @@ udl_fb_user_fb_create(struct drm_device |
| struct drm_file *file, |
| const struct drm_mode_fb_cmd2 *mode_cmd); |
| |
| -int udl_render_hline(struct drm_device *dev, int bpp, struct urb **urb_ptr, |
| +int udl_render_hline(struct drm_device *dev, int log_bpp, struct urb **urb_ptr, |
| const char *front, char **urb_buf_ptr, |
| u32 byte_offset, u32 device_byte_offset, u32 byte_width, |
| int *ident_ptr, int *sent_ptr); |
| --- a/drivers/gpu/drm/udl/udl_fb.c |
| +++ b/drivers/gpu/drm/udl/udl_fb.c |
| @@ -90,7 +90,10 @@ int udl_handle_damage(struct udl_framebu |
| int bytes_identical = 0; |
| struct urb *urb; |
| int aligned_x; |
| - int bpp = fb->base.format->cpp[0]; |
| + int log_bpp; |
| + |
| + BUG_ON(!is_power_of_2(fb->base.format->cpp[0])); |
| + log_bpp = __ffs(fb->base.format->cpp[0]); |
| |
| if (!fb->active_16) |
| return 0; |
| @@ -125,12 +128,12 @@ int udl_handle_damage(struct udl_framebu |
| |
| for (i = y; i < y + height ; i++) { |
| const int line_offset = fb->base.pitches[0] * i; |
| - const int byte_offset = line_offset + (x * bpp); |
| - const int dev_byte_offset = (fb->base.width * bpp * i) + (x * bpp); |
| - if (udl_render_hline(dev, bpp, &urb, |
| + const int byte_offset = line_offset + (x << log_bpp); |
| + const int dev_byte_offset = (fb->base.width * i + x) << log_bpp; |
| + if (udl_render_hline(dev, log_bpp, &urb, |
| (char *) fb->obj->vmapping, |
| &cmd, byte_offset, dev_byte_offset, |
| - width * bpp, |
| + width << log_bpp, |
| &bytes_identical, &bytes_sent)) |
| goto error; |
| } |
| @@ -149,7 +152,7 @@ int udl_handle_damage(struct udl_framebu |
| error: |
| atomic_add(bytes_sent, &udl->bytes_sent); |
| atomic_add(bytes_identical, &udl->bytes_identical); |
| - atomic_add(width*height*bpp, &udl->bytes_rendered); |
| + atomic_add((width * height) << log_bpp, &udl->bytes_rendered); |
| end_cycles = get_cycles(); |
| atomic_add(((unsigned int) ((end_cycles - start_cycles) |
| >> 10)), /* Kcycles */ |
| --- a/drivers/gpu/drm/udl/udl_transfer.c |
| +++ b/drivers/gpu/drm/udl/udl_transfer.c |
| @@ -83,12 +83,12 @@ static inline u16 pixel32_to_be16(const |
| ((pixel >> 8) & 0xf800)); |
| } |
| |
| -static inline u16 get_pixel_val16(const uint8_t *pixel, int bpp) |
| +static inline u16 get_pixel_val16(const uint8_t *pixel, int log_bpp) |
| { |
| - u16 pixel_val16 = 0; |
| - if (bpp == 2) |
| + u16 pixel_val16; |
| + if (log_bpp == 1) |
| pixel_val16 = *(const uint16_t *)pixel; |
| - else if (bpp == 4) |
| + else |
| pixel_val16 = pixel32_to_be16(*(const uint32_t *)pixel); |
| return pixel_val16; |
| } |
| @@ -125,8 +125,9 @@ static void udl_compress_hline16( |
| const u8 *const pixel_end, |
| uint32_t *device_address_ptr, |
| uint8_t **command_buffer_ptr, |
| - const uint8_t *const cmd_buffer_end, int bpp) |
| + const uint8_t *const cmd_buffer_end, int log_bpp) |
| { |
| + const int bpp = 1 << log_bpp; |
| const u8 *pixel = *pixel_start_ptr; |
| uint32_t dev_addr = *device_address_ptr; |
| uint8_t *cmd = *command_buffer_ptr; |
| @@ -153,12 +154,12 @@ static void udl_compress_hline16( |
| raw_pixels_count_byte = cmd++; /* we'll know this later */ |
| raw_pixel_start = pixel; |
| |
| - cmd_pixel_end = pixel + min3(MAX_CMD_PIXELS + 1UL, |
| - (unsigned long)(pixel_end - pixel) / bpp, |
| - (unsigned long)(cmd_buffer_end - 1 - cmd) / 2) * bpp; |
| + cmd_pixel_end = pixel + (min3(MAX_CMD_PIXELS + 1UL, |
| + (unsigned long)(pixel_end - pixel) >> log_bpp, |
| + (unsigned long)(cmd_buffer_end - 1 - cmd) / 2) << log_bpp); |
| |
| prefetch_range((void *) pixel, cmd_pixel_end - pixel); |
| - pixel_val16 = get_pixel_val16(pixel, bpp); |
| + pixel_val16 = get_pixel_val16(pixel, log_bpp); |
| |
| while (pixel < cmd_pixel_end) { |
| const u8 *const start = pixel; |
| @@ -170,7 +171,7 @@ static void udl_compress_hline16( |
| pixel += bpp; |
| |
| while (pixel < cmd_pixel_end) { |
| - pixel_val16 = get_pixel_val16(pixel, bpp); |
| + pixel_val16 = get_pixel_val16(pixel, log_bpp); |
| if (pixel_val16 != repeating_pixel_val16) |
| break; |
| pixel += bpp; |
| @@ -179,10 +180,10 @@ static void udl_compress_hline16( |
| if (unlikely(pixel > start + bpp)) { |
| /* go back and fill in raw pixel count */ |
| *raw_pixels_count_byte = (((start - |
| - raw_pixel_start) / bpp) + 1) & 0xFF; |
| + raw_pixel_start) >> log_bpp) + 1) & 0xFF; |
| |
| /* immediately after raw data is repeat byte */ |
| - *cmd++ = (((pixel - start) / bpp) - 1) & 0xFF; |
| + *cmd++ = (((pixel - start) >> log_bpp) - 1) & 0xFF; |
| |
| /* Then start another raw pixel span */ |
| raw_pixel_start = pixel; |
| @@ -192,14 +193,14 @@ static void udl_compress_hline16( |
| |
| if (pixel > raw_pixel_start) { |
| /* finalize last RAW span */ |
| - *raw_pixels_count_byte = ((pixel-raw_pixel_start) / bpp) & 0xFF; |
| + *raw_pixels_count_byte = ((pixel - raw_pixel_start) >> log_bpp) & 0xFF; |
| } else { |
| /* undo unused byte */ |
| cmd--; |
| } |
| |
| - *cmd_pixels_count_byte = ((pixel - cmd_pixel_start) / bpp) & 0xFF; |
| - dev_addr += ((pixel - cmd_pixel_start) / bpp) * 2; |
| + *cmd_pixels_count_byte = ((pixel - cmd_pixel_start) >> log_bpp) & 0xFF; |
| + dev_addr += ((pixel - cmd_pixel_start) >> log_bpp) * 2; |
| } |
| |
| if (cmd_buffer_end <= MIN_RLX_CMD_BYTES + cmd) { |
| @@ -222,19 +223,19 @@ static void udl_compress_hline16( |
| * (that we can only write to, slowly, and can never read), and (optionally) |
| * our shadow copy that tracks what's been sent to that hardware buffer. |
| */ |
| -int udl_render_hline(struct drm_device *dev, int bpp, struct urb **urb_ptr, |
| +int udl_render_hline(struct drm_device *dev, int log_bpp, struct urb **urb_ptr, |
| const char *front, char **urb_buf_ptr, |
| u32 byte_offset, u32 device_byte_offset, |
| u32 byte_width, |
| int *ident_ptr, int *sent_ptr) |
| { |
| const u8 *line_start, *line_end, *next_pixel; |
| - u32 base16 = 0 + (device_byte_offset / bpp) * 2; |
| + u32 base16 = 0 + (device_byte_offset >> log_bpp) * 2; |
| struct urb *urb = *urb_ptr; |
| u8 *cmd = *urb_buf_ptr; |
| u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length; |
| |
| - BUG_ON(!(bpp == 2 || bpp == 4)); |
| + BUG_ON(!(log_bpp == 1 || log_bpp == 2)); |
| |
| line_start = (u8 *) (front + byte_offset); |
| next_pixel = line_start; |
| @@ -244,7 +245,7 @@ int udl_render_hline(struct drm_device * |
| |
| udl_compress_hline16(&next_pixel, |
| line_end, &base16, |
| - (u8 **) &cmd, (u8 *) cmd_end, bpp); |
| + (u8 **) &cmd, (u8 *) cmd_end, log_bpp); |
| |
| if (cmd >= cmd_end) { |
| int len = cmd - (u8 *) urb->transfer_buffer; |