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1/*
2 * Copyright (C) 2012 Red Hat
3 * based in parts on udlfb.c:
4 * Copyright (C) 2009 Roberto De Ioris <roberto@unbit.it>
5 * Copyright (C) 2009 Jaya Kumar <jayakumar.lkml@gmail.com>
6 * Copyright (C) 2009 Bernie Thompson <bernie@plugable.com>
7 *
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License v2. See the file COPYING in the main directory of this archive for
10 * more details.
11 */
12
13#include <linux/module.h>
14#include <linux/slab.h>
15#include <linux/fb.h>
16#include <linux/prefetch.h>
17
18#include <drm/drmP.h>
19#include "udl_drv.h"
20
21#define MAX_CMD_PIXELS 255
22
23#define RLX_HEADER_BYTES 7
24#define MIN_RLX_PIX_BYTES 4
25#define MIN_RLX_CMD_BYTES (RLX_HEADER_BYTES + MIN_RLX_PIX_BYTES)
26
27#define RLE_HEADER_BYTES 6
28#define MIN_RLE_PIX_BYTES 3
29#define MIN_RLE_CMD_BYTES (RLE_HEADER_BYTES + MIN_RLE_PIX_BYTES)
30
31#define RAW_HEADER_BYTES 6
32#define MIN_RAW_PIX_BYTES 2
33#define MIN_RAW_CMD_BYTES (RAW_HEADER_BYTES + MIN_RAW_PIX_BYTES)
34
35/*
36 * Trims identical data from front and back of line
37 * Sets new front buffer address and width
38 * And returns byte count of identical pixels
39 * Assumes CPU natural alignment (unsigned long)
40 * for back and front buffer ptrs and width
41 */
42#if 0
43static int udl_trim_hline(const u8 *bback, const u8 **bfront, int *width_bytes)
44{
45 int j, k;
46 const unsigned long *back = (const unsigned long *) bback;
47 const unsigned long *front = (const unsigned long *) *bfront;
48 const int width = *width_bytes / sizeof(unsigned long);
49 int identical = width;
50 int start = width;
51 int end = width;
52
53 prefetch((void *) front);
54 prefetch((void *) back);
55
56 for (j = 0; j < width; j++) {
57 if (back[j] != front[j]) {
58 start = j;
59 break;
60 }
61 }
62
63 for (k = width - 1; k > j; k--) {
64 if (back[k] != front[k]) {
65 end = k+1;
66 break;
67 }
68 }
69
70 identical = start + (width - end);
71 *bfront = (u8 *) &front[start];
72 *width_bytes = (end - start) * sizeof(unsigned long);
73
74 return identical * sizeof(unsigned long);
75}
76#endif
77
78static inline u16 pixel32_to_be16(const uint32_t pixel)
79{
80 return (((pixel >> 3) & 0x001f) |
81 ((pixel >> 5) & 0x07e0) |
82 ((pixel >> 8) & 0xf800));
83}
84
85static inline u16 get_pixel_val16(const uint8_t *pixel, int bpp)
86{
87 u16 pixel_val16 = 0;
88 if (bpp == 2)
89 pixel_val16 = *(const uint16_t *)pixel;
90 else if (bpp == 4)
91 pixel_val16 = pixel32_to_be16(*(const uint32_t *)pixel);
92 return pixel_val16;
93}
94
95/*
96 * Render a command stream for an encoded horizontal line segment of pixels.
97 *
98 * A command buffer holds several commands.
99 * It always begins with a fresh command header
100 * (the protocol doesn't require this, but we enforce it to allow
101 * multiple buffers to be potentially encoded and sent in parallel).
102 * A single command encodes one contiguous horizontal line of pixels
103 *
104 * The function relies on the client to do all allocation, so that
105 * rendering can be done directly to output buffers (e.g. USB URBs).
106 * The function fills the supplied command buffer, providing information
107 * on where it left off, so the client may call in again with additional
108 * buffers if the line will take several buffers to complete.
109 *
110 * A single command can transmit a maximum of 256 pixels,
111 * regardless of the compression ratio (protocol design limit).
112 * To the hardware, 0 for a size byte means 256
113 *
114 * Rather than 256 pixel commands which are either rl or raw encoded,
115 * the rlx command simply assumes alternating raw and rl spans within one cmd.
116 * This has a slightly larger header overhead, but produces more even results.
117 * It also processes all data (read and write) in a single pass.
118 * Performance benchmarks of common cases show it having just slightly better
119 * compression than 256 pixel raw or rle commands, with similar CPU consumpion.
120 * But for very rl friendly data, will compress not quite as well.
121 */
122static void udl_compress_hline16(
123 const u8 **pixel_start_ptr,
124 const u8 *const pixel_end,
125 uint32_t *device_address_ptr,
126 uint8_t **command_buffer_ptr,
127 const uint8_t *const cmd_buffer_end, int bpp)
128{
129 const u8 *pixel = *pixel_start_ptr;
130 uint32_t dev_addr = *device_address_ptr;
131 uint8_t *cmd = *command_buffer_ptr;
132
133 while ((pixel_end > pixel) &&
134 (cmd_buffer_end - MIN_RLX_CMD_BYTES > cmd)) {
135 uint8_t *raw_pixels_count_byte = NULL;
136 uint8_t *cmd_pixels_count_byte = NULL;
137 const u8 *raw_pixel_start = NULL;
138 const u8 *cmd_pixel_start, *cmd_pixel_end = NULL;
139 uint16_t pixel_val16;
140
141 prefetchw((void *) cmd); /* pull in one cache line at least */
142
143 *cmd++ = 0xaf;
144 *cmd++ = 0x6b;
145 *cmd++ = (uint8_t) ((dev_addr >> 16) & 0xFF);
146 *cmd++ = (uint8_t) ((dev_addr >> 8) & 0xFF);
147 *cmd++ = (uint8_t) ((dev_addr) & 0xFF);
148
149 cmd_pixels_count_byte = cmd++; /* we'll know this later */
150 cmd_pixel_start = pixel;
151
152 raw_pixels_count_byte = cmd++; /* we'll know this later */
153 raw_pixel_start = pixel;
154
155 cmd_pixel_end = pixel + (min(MAX_CMD_PIXELS + 1,
156 min((int)(pixel_end - pixel) / bpp,
157 (int)(cmd_buffer_end - cmd) / 2))) * bpp;
158
159 prefetch_range((void *) pixel, (cmd_pixel_end - pixel) * bpp);
160 pixel_val16 = get_pixel_val16(pixel, bpp);
161
162 while (pixel < cmd_pixel_end) {
163 const u8 *const start = pixel;
164 const uint16_t repeating_pixel_val16 = pixel_val16;
165
166 *(uint16_t *)cmd = cpu_to_be16(pixel_val16);
167
168 cmd += 2;
169 pixel += bpp;
170
171 while (pixel < cmd_pixel_end) {
172 pixel_val16 = get_pixel_val16(pixel, bpp);
173 if (pixel_val16 != repeating_pixel_val16)
174 break;
175 pixel += bpp;
176 }
177
178 if (unlikely(pixel > start + bpp)) {
179 /* go back and fill in raw pixel count */
180 *raw_pixels_count_byte = (((start -
181 raw_pixel_start) / bpp) + 1) & 0xFF;
182
183 /* immediately after raw data is repeat byte */
184 *cmd++ = (((pixel - start) / bpp) - 1) & 0xFF;
185
186 /* Then start another raw pixel span */
187 raw_pixel_start = pixel;
188 raw_pixels_count_byte = cmd++;
189 }
190 }
191
192 if (pixel > raw_pixel_start) {
193 /* finalize last RAW span */
194 *raw_pixels_count_byte = ((pixel-raw_pixel_start) / bpp) & 0xFF;
195 }
196
197 *cmd_pixels_count_byte = ((pixel - cmd_pixel_start) / bpp) & 0xFF;
198 dev_addr += ((pixel - cmd_pixel_start) / bpp) * 2;
199 }
200
201 if (cmd_buffer_end <= MIN_RLX_CMD_BYTES + cmd) {
202 /* Fill leftover bytes with no-ops */
203 if (cmd_buffer_end > cmd)
204 memset(cmd, 0xAF, cmd_buffer_end - cmd);
205 cmd = (uint8_t *) cmd_buffer_end;
206 }
207
208 *command_buffer_ptr = cmd;
209 *pixel_start_ptr = pixel;
210 *device_address_ptr = dev_addr;
211
212 return;
213}
214
215/*
216 * There are 3 copies of every pixel: The front buffer that the fbdev
217 * client renders to, the actual framebuffer across the USB bus in hardware
218 * (that we can only write to, slowly, and can never read), and (optionally)
219 * our shadow copy that tracks what's been sent to that hardware buffer.
220 */
221int udl_render_hline(struct drm_device *dev, int bpp, struct urb **urb_ptr,
222 const char *front, char **urb_buf_ptr,
223 u32 byte_offset, u32 device_byte_offset,
224 u32 byte_width,
225 int *ident_ptr, int *sent_ptr)
226{
227 const u8 *line_start, *line_end, *next_pixel;
228 u32 base16 = 0 + (device_byte_offset / bpp) * 2;
229 struct urb *urb = *urb_ptr;
230 u8 *cmd = *urb_buf_ptr;
231 u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
232
233 BUG_ON(!(bpp == 2 || bpp == 4));
234
235 line_start = (u8 *) (front + byte_offset);
236 next_pixel = line_start;
237 line_end = next_pixel + byte_width;
238
239 while (next_pixel < line_end) {
240
241 udl_compress_hline16(&next_pixel,
242 line_end, &base16,
243 (u8 **) &cmd, (u8 *) cmd_end, bpp);
244
245 if (cmd >= cmd_end) {
246 int len = cmd - (u8 *) urb->transfer_buffer;
247 if (udl_submit_urb(dev, urb, len))
248 return 1; /* lost pixels is set */
249 *sent_ptr += len;
250 urb = udl_get_urb(dev);
251 if (!urb)
252 return 1; /* lost_pixels is set */
253 *urb_ptr = urb;
254 cmd = urb->transfer_buffer;
255 cmd_end = &cmd[urb->transfer_buffer_length];
256 }
257 }
258
259 *urb_buf_ptr = cmd;
260
261 return 0;
262}
263
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Red Hat
4 * based in parts on udlfb.c:
5 * Copyright (C) 2009 Roberto De Ioris <roberto@unbit.it>
6 * Copyright (C) 2009 Jaya Kumar <jayakumar.lkml@gmail.com>
7 * Copyright (C) 2009 Bernie Thompson <bernie@plugable.com>
8 */
9
10#include <asm/unaligned.h>
11
12#include "udl_drv.h"
13
14#define MAX_CMD_PIXELS 255
15
16#define RLX_HEADER_BYTES 7
17#define MIN_RLX_PIX_BYTES 4
18#define MIN_RLX_CMD_BYTES (RLX_HEADER_BYTES + MIN_RLX_PIX_BYTES)
19
20#define RLE_HEADER_BYTES 6
21#define MIN_RLE_PIX_BYTES 3
22#define MIN_RLE_CMD_BYTES (RLE_HEADER_BYTES + MIN_RLE_PIX_BYTES)
23
24#define RAW_HEADER_BYTES 6
25#define MIN_RAW_PIX_BYTES 2
26#define MIN_RAW_CMD_BYTES (RAW_HEADER_BYTES + MIN_RAW_PIX_BYTES)
27
28/*
29 * Trims identical data from front and back of line
30 * Sets new front buffer address and width
31 * And returns byte count of identical pixels
32 * Assumes CPU natural alignment (unsigned long)
33 * for back and front buffer ptrs and width
34 */
35#if 0
36static int udl_trim_hline(const u8 *bback, const u8 **bfront, int *width_bytes)
37{
38 int j, k;
39 const unsigned long *back = (const unsigned long *) bback;
40 const unsigned long *front = (const unsigned long *) *bfront;
41 const int width = *width_bytes / sizeof(unsigned long);
42 int identical = width;
43 int start = width;
44 int end = width;
45
46 for (j = 0; j < width; j++) {
47 if (back[j] != front[j]) {
48 start = j;
49 break;
50 }
51 }
52
53 for (k = width - 1; k > j; k--) {
54 if (back[k] != front[k]) {
55 end = k+1;
56 break;
57 }
58 }
59
60 identical = start + (width - end);
61 *bfront = (u8 *) &front[start];
62 *width_bytes = (end - start) * sizeof(unsigned long);
63
64 return identical * sizeof(unsigned long);
65}
66#endif
67
68static inline u16 pixel32_to_be16(const uint32_t pixel)
69{
70 return (((pixel >> 3) & 0x001f) |
71 ((pixel >> 5) & 0x07e0) |
72 ((pixel >> 8) & 0xf800));
73}
74
75static inline u16 get_pixel_val16(const uint8_t *pixel, int log_bpp)
76{
77 u16 pixel_val16;
78 if (log_bpp == 1)
79 pixel_val16 = *(const uint16_t *)pixel;
80 else
81 pixel_val16 = pixel32_to_be16(*(const uint32_t *)pixel);
82 return pixel_val16;
83}
84
85/*
86 * Render a command stream for an encoded horizontal line segment of pixels.
87 *
88 * A command buffer holds several commands.
89 * It always begins with a fresh command header
90 * (the protocol doesn't require this, but we enforce it to allow
91 * multiple buffers to be potentially encoded and sent in parallel).
92 * A single command encodes one contiguous horizontal line of pixels
93 *
94 * The function relies on the client to do all allocation, so that
95 * rendering can be done directly to output buffers (e.g. USB URBs).
96 * The function fills the supplied command buffer, providing information
97 * on where it left off, so the client may call in again with additional
98 * buffers if the line will take several buffers to complete.
99 *
100 * A single command can transmit a maximum of 256 pixels,
101 * regardless of the compression ratio (protocol design limit).
102 * To the hardware, 0 for a size byte means 256
103 *
104 * Rather than 256 pixel commands which are either rl or raw encoded,
105 * the rlx command simply assumes alternating raw and rl spans within one cmd.
106 * This has a slightly larger header overhead, but produces more even results.
107 * It also processes all data (read and write) in a single pass.
108 * Performance benchmarks of common cases show it having just slightly better
109 * compression than 256 pixel raw or rle commands, with similar CPU consumpion.
110 * But for very rl friendly data, will compress not quite as well.
111 */
112static void udl_compress_hline16(
113 const u8 **pixel_start_ptr,
114 const u8 *const pixel_end,
115 uint32_t *device_address_ptr,
116 uint8_t **command_buffer_ptr,
117 const uint8_t *const cmd_buffer_end, int log_bpp)
118{
119 const int bpp = 1 << log_bpp;
120 const u8 *pixel = *pixel_start_ptr;
121 uint32_t dev_addr = *device_address_ptr;
122 uint8_t *cmd = *command_buffer_ptr;
123
124 while ((pixel_end > pixel) &&
125 (cmd_buffer_end - MIN_RLX_CMD_BYTES > cmd)) {
126 uint8_t *raw_pixels_count_byte = NULL;
127 uint8_t *cmd_pixels_count_byte = NULL;
128 const u8 *raw_pixel_start = NULL;
129 const u8 *cmd_pixel_start, *cmd_pixel_end = NULL;
130 uint16_t pixel_val16;
131
132 *cmd++ = 0xaf;
133 *cmd++ = 0x6b;
134 *cmd++ = (uint8_t) ((dev_addr >> 16) & 0xFF);
135 *cmd++ = (uint8_t) ((dev_addr >> 8) & 0xFF);
136 *cmd++ = (uint8_t) ((dev_addr) & 0xFF);
137
138 cmd_pixels_count_byte = cmd++; /* we'll know this later */
139 cmd_pixel_start = pixel;
140
141 raw_pixels_count_byte = cmd++; /* we'll know this later */
142 raw_pixel_start = pixel;
143
144 cmd_pixel_end = pixel + (min3(MAX_CMD_PIXELS + 1UL,
145 (unsigned long)(pixel_end - pixel) >> log_bpp,
146 (unsigned long)(cmd_buffer_end - 1 - cmd) / 2) << log_bpp);
147
148 pixel_val16 = get_pixel_val16(pixel, log_bpp);
149
150 while (pixel < cmd_pixel_end) {
151 const u8 *const start = pixel;
152 const uint16_t repeating_pixel_val16 = pixel_val16;
153
154 put_unaligned_be16(pixel_val16, cmd);
155
156 cmd += 2;
157 pixel += bpp;
158
159 while (pixel < cmd_pixel_end) {
160 pixel_val16 = get_pixel_val16(pixel, log_bpp);
161 if (pixel_val16 != repeating_pixel_val16)
162 break;
163 pixel += bpp;
164 }
165
166 if (unlikely(pixel > start + bpp)) {
167 /* go back and fill in raw pixel count */
168 *raw_pixels_count_byte = (((start -
169 raw_pixel_start) >> log_bpp) + 1) & 0xFF;
170
171 /* immediately after raw data is repeat byte */
172 *cmd++ = (((pixel - start) >> log_bpp) - 1) & 0xFF;
173
174 /* Then start another raw pixel span */
175 raw_pixel_start = pixel;
176 raw_pixels_count_byte = cmd++;
177 }
178 }
179
180 if (pixel > raw_pixel_start) {
181 /* finalize last RAW span */
182 *raw_pixels_count_byte = ((pixel - raw_pixel_start) >> log_bpp) & 0xFF;
183 } else {
184 /* undo unused byte */
185 cmd--;
186 }
187
188 *cmd_pixels_count_byte = ((pixel - cmd_pixel_start) >> log_bpp) & 0xFF;
189 dev_addr += ((pixel - cmd_pixel_start) >> log_bpp) * 2;
190 }
191
192 if (cmd_buffer_end <= MIN_RLX_CMD_BYTES + cmd) {
193 /* Fill leftover bytes with no-ops */
194 if (cmd_buffer_end > cmd)
195 memset(cmd, 0xAF, cmd_buffer_end - cmd);
196 cmd = (uint8_t *) cmd_buffer_end;
197 }
198
199 *command_buffer_ptr = cmd;
200 *pixel_start_ptr = pixel;
201 *device_address_ptr = dev_addr;
202
203 return;
204}
205
206/*
207 * There are 3 copies of every pixel: The front buffer that the fbdev
208 * client renders to, the actual framebuffer across the USB bus in hardware
209 * (that we can only write to, slowly, and can never read), and (optionally)
210 * our shadow copy that tracks what's been sent to that hardware buffer.
211 */
212int udl_render_hline(struct drm_device *dev, int log_bpp, struct urb **urb_ptr,
213 const char *front, char **urb_buf_ptr,
214 u32 byte_offset, u32 device_byte_offset,
215 u32 byte_width)
216{
217 const u8 *line_start, *line_end, *next_pixel;
218 u32 base16 = 0 + (device_byte_offset >> log_bpp) * 2;
219 struct urb *urb = *urb_ptr;
220 u8 *cmd = *urb_buf_ptr;
221 u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
222
223 BUG_ON(!(log_bpp == 1 || log_bpp == 2));
224
225 line_start = (u8 *) (front + byte_offset);
226 next_pixel = line_start;
227 line_end = next_pixel + byte_width;
228
229 while (next_pixel < line_end) {
230
231 udl_compress_hline16(&next_pixel,
232 line_end, &base16,
233 (u8 **) &cmd, (u8 *) cmd_end, log_bpp);
234
235 if (cmd >= cmd_end) {
236 int len = cmd - (u8 *) urb->transfer_buffer;
237 int ret = udl_submit_urb(dev, urb, len);
238 if (ret)
239 return ret;
240 urb = udl_get_urb(dev);
241 if (!urb)
242 return -EAGAIN;
243 *urb_ptr = urb;
244 cmd = urb->transfer_buffer;
245 cmd_end = &cmd[urb->transfer_buffer_length];
246 }
247 }
248
249 *urb_buf_ptr = cmd;
250
251 return 0;
252}