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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#include "udl_proto.h"
14
15#define MAX_CMD_PIXELS 255
16
17#define RLX_HEADER_BYTES 7
18#define MIN_RLX_PIX_BYTES 4
19#define MIN_RLX_CMD_BYTES (RLX_HEADER_BYTES + MIN_RLX_PIX_BYTES)
20
21#define RLE_HEADER_BYTES 6
22#define MIN_RLE_PIX_BYTES 3
23#define MIN_RLE_CMD_BYTES (RLE_HEADER_BYTES + MIN_RLE_PIX_BYTES)
24
25#define RAW_HEADER_BYTES 6
26#define MIN_RAW_PIX_BYTES 2
27#define MIN_RAW_CMD_BYTES (RAW_HEADER_BYTES + MIN_RAW_PIX_BYTES)
28
29static inline u16 pixel32_to_be16(const uint32_t pixel)
30{
31 return (((pixel >> 3) & 0x001f) |
32 ((pixel >> 5) & 0x07e0) |
33 ((pixel >> 8) & 0xf800));
34}
35
36static inline u16 get_pixel_val16(const uint8_t *pixel, int log_bpp)
37{
38 u16 pixel_val16;
39 if (log_bpp == 1)
40 pixel_val16 = *(const uint16_t *)pixel;
41 else
42 pixel_val16 = pixel32_to_be16(*(const uint32_t *)pixel);
43 return pixel_val16;
44}
45
46/*
47 * Render a command stream for an encoded horizontal line segment of pixels.
48 *
49 * A command buffer holds several commands.
50 * It always begins with a fresh command header
51 * (the protocol doesn't require this, but we enforce it to allow
52 * multiple buffers to be potentially encoded and sent in parallel).
53 * A single command encodes one contiguous horizontal line of pixels
54 *
55 * The function relies on the client to do all allocation, so that
56 * rendering can be done directly to output buffers (e.g. USB URBs).
57 * The function fills the supplied command buffer, providing information
58 * on where it left off, so the client may call in again with additional
59 * buffers if the line will take several buffers to complete.
60 *
61 * A single command can transmit a maximum of 256 pixels,
62 * regardless of the compression ratio (protocol design limit).
63 * To the hardware, 0 for a size byte means 256
64 *
65 * Rather than 256 pixel commands which are either rl or raw encoded,
66 * the rlx command simply assumes alternating raw and rl spans within one cmd.
67 * This has a slightly larger header overhead, but produces more even results.
68 * It also processes all data (read and write) in a single pass.
69 * Performance benchmarks of common cases show it having just slightly better
70 * compression than 256 pixel raw or rle commands, with similar CPU consumpion.
71 * But for very rl friendly data, will compress not quite as well.
72 */
73static void udl_compress_hline16(
74 const u8 **pixel_start_ptr,
75 const u8 *const pixel_end,
76 uint32_t *device_address_ptr,
77 uint8_t **command_buffer_ptr,
78 const uint8_t *const cmd_buffer_end, int log_bpp)
79{
80 const int bpp = 1 << log_bpp;
81 const u8 *pixel = *pixel_start_ptr;
82 uint32_t dev_addr = *device_address_ptr;
83 uint8_t *cmd = *command_buffer_ptr;
84
85 while ((pixel_end > pixel) &&
86 (cmd_buffer_end - MIN_RLX_CMD_BYTES > cmd)) {
87 uint8_t *raw_pixels_count_byte = NULL;
88 uint8_t *cmd_pixels_count_byte = NULL;
89 const u8 *raw_pixel_start = NULL;
90 const u8 *cmd_pixel_start, *cmd_pixel_end = NULL;
91 uint16_t pixel_val16;
92
93 *cmd++ = UDL_MSG_BULK;
94 *cmd++ = UDL_CMD_WRITERLX16;
95 *cmd++ = (uint8_t) ((dev_addr >> 16) & 0xFF);
96 *cmd++ = (uint8_t) ((dev_addr >> 8) & 0xFF);
97 *cmd++ = (uint8_t) ((dev_addr) & 0xFF);
98
99 cmd_pixels_count_byte = cmd++; /* we'll know this later */
100 cmd_pixel_start = pixel;
101
102 raw_pixels_count_byte = cmd++; /* we'll know this later */
103 raw_pixel_start = pixel;
104
105 cmd_pixel_end = pixel + (min3(MAX_CMD_PIXELS + 1UL,
106 (unsigned long)(pixel_end - pixel) >> log_bpp,
107 (unsigned long)(cmd_buffer_end - 1 - cmd) / 2) << log_bpp);
108
109 pixel_val16 = get_pixel_val16(pixel, log_bpp);
110
111 while (pixel < cmd_pixel_end) {
112 const u8 *const start = pixel;
113 const uint16_t repeating_pixel_val16 = pixel_val16;
114
115 put_unaligned_be16(pixel_val16, cmd);
116
117 cmd += 2;
118 pixel += bpp;
119
120 while (pixel < cmd_pixel_end) {
121 pixel_val16 = get_pixel_val16(pixel, log_bpp);
122 if (pixel_val16 != repeating_pixel_val16)
123 break;
124 pixel += bpp;
125 }
126
127 if (unlikely(pixel > start + bpp)) {
128 /* go back and fill in raw pixel count */
129 *raw_pixels_count_byte = (((start -
130 raw_pixel_start) >> log_bpp) + 1) & 0xFF;
131
132 /* immediately after raw data is repeat byte */
133 *cmd++ = (((pixel - start) >> log_bpp) - 1) & 0xFF;
134
135 /* Then start another raw pixel span */
136 raw_pixel_start = pixel;
137 raw_pixels_count_byte = cmd++;
138 }
139 }
140
141 if (pixel > raw_pixel_start) {
142 /* finalize last RAW span */
143 *raw_pixels_count_byte = ((pixel - raw_pixel_start) >> log_bpp) & 0xFF;
144 } else {
145 /* undo unused byte */
146 cmd--;
147 }
148
149 *cmd_pixels_count_byte = ((pixel - cmd_pixel_start) >> log_bpp) & 0xFF;
150 dev_addr += ((pixel - cmd_pixel_start) >> log_bpp) * 2;
151 }
152
153 if (cmd_buffer_end <= MIN_RLX_CMD_BYTES + cmd) {
154 /* Fill leftover bytes with no-ops */
155 if (cmd_buffer_end > cmd)
156 memset(cmd, UDL_MSG_BULK, cmd_buffer_end - cmd);
157 cmd = (uint8_t *) cmd_buffer_end;
158 }
159
160 *command_buffer_ptr = cmd;
161 *pixel_start_ptr = pixel;
162 *device_address_ptr = dev_addr;
163
164 return;
165}
166
167/*
168 * There are 3 copies of every pixel: The front buffer that the fbdev
169 * client renders to, the actual framebuffer across the USB bus in hardware
170 * (that we can only write to, slowly, and can never read), and (optionally)
171 * our shadow copy that tracks what's been sent to that hardware buffer.
172 */
173int udl_render_hline(struct drm_device *dev, int log_bpp, struct urb **urb_ptr,
174 const char *front, char **urb_buf_ptr,
175 u32 byte_offset, u32 device_byte_offset,
176 u32 byte_width)
177{
178 const u8 *line_start, *line_end, *next_pixel;
179 u32 base16 = 0 + (device_byte_offset >> log_bpp) * 2;
180 struct urb *urb = *urb_ptr;
181 u8 *cmd = *urb_buf_ptr;
182 u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
183
184 if (WARN_ON(!(log_bpp == 1 || log_bpp == 2))) {
185 /* need to finish URB at error from this function */
186 udl_urb_completion(urb);
187 return -EINVAL;
188 }
189
190 line_start = (u8 *) (front + byte_offset);
191 next_pixel = line_start;
192 line_end = next_pixel + byte_width;
193
194 while (next_pixel < line_end) {
195
196 udl_compress_hline16(&next_pixel,
197 line_end, &base16,
198 (u8 **) &cmd, (u8 *) cmd_end, log_bpp);
199
200 if (cmd >= cmd_end) {
201 int len = cmd - (u8 *) urb->transfer_buffer;
202 int ret = udl_submit_urb(dev, urb, len);
203 if (ret)
204 return ret;
205 urb = udl_get_urb(dev);
206 if (!urb)
207 return -EAGAIN;
208 *urb_ptr = urb;
209 cmd = urb->transfer_buffer;
210 cmd_end = &cmd[urb->transfer_buffer_length];
211 }
212 }
213
214 *urb_buf_ptr = cmd;
215
216 return 0;
217}
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 "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_be16p(const uint8_t *pixel)
79{
80 uint32_t pix = *(uint32_t *)pixel;
81 u16 retval;
82
83 retval = (((pix >> 3) & 0x001f) |
84 ((pix >> 5) & 0x07e0) |
85 ((pix >> 8) & 0xf800));
86 return retval;
87}
88
89/*
90 * Render a command stream for an encoded horizontal line segment of pixels.
91 *
92 * A command buffer holds several commands.
93 * It always begins with a fresh command header
94 * (the protocol doesn't require this, but we enforce it to allow
95 * multiple buffers to be potentially encoded and sent in parallel).
96 * A single command encodes one contiguous horizontal line of pixels
97 *
98 * The function relies on the client to do all allocation, so that
99 * rendering can be done directly to output buffers (e.g. USB URBs).
100 * The function fills the supplied command buffer, providing information
101 * on where it left off, so the client may call in again with additional
102 * buffers if the line will take several buffers to complete.
103 *
104 * A single command can transmit a maximum of 256 pixels,
105 * regardless of the compression ratio (protocol design limit).
106 * To the hardware, 0 for a size byte means 256
107 *
108 * Rather than 256 pixel commands which are either rl or raw encoded,
109 * the rlx command simply assumes alternating raw and rl spans within one cmd.
110 * This has a slightly larger header overhead, but produces more even results.
111 * It also processes all data (read and write) in a single pass.
112 * Performance benchmarks of common cases show it having just slightly better
113 * compression than 256 pixel raw or rle commands, with similar CPU consumpion.
114 * But for very rl friendly data, will compress not quite as well.
115 */
116static void udl_compress_hline16(
117 const u8 **pixel_start_ptr,
118 const u8 *const pixel_end,
119 uint32_t *device_address_ptr,
120 uint8_t **command_buffer_ptr,
121 const uint8_t *const cmd_buffer_end, int bpp)
122{
123 const u8 *pixel = *pixel_start_ptr;
124 uint32_t dev_addr = *device_address_ptr;
125 uint8_t *cmd = *command_buffer_ptr;
126
127 while ((pixel_end > pixel) &&
128 (cmd_buffer_end - MIN_RLX_CMD_BYTES > cmd)) {
129 uint8_t *raw_pixels_count_byte = 0;
130 uint8_t *cmd_pixels_count_byte = 0;
131 const u8 *raw_pixel_start = 0;
132 const u8 *cmd_pixel_start, *cmd_pixel_end = 0;
133
134 prefetchw((void *) cmd); /* pull in one cache line at least */
135
136 *cmd++ = 0xaf;
137 *cmd++ = 0x6b;
138 *cmd++ = (uint8_t) ((dev_addr >> 16) & 0xFF);
139 *cmd++ = (uint8_t) ((dev_addr >> 8) & 0xFF);
140 *cmd++ = (uint8_t) ((dev_addr) & 0xFF);
141
142 cmd_pixels_count_byte = cmd++; /* we'll know this later */
143 cmd_pixel_start = pixel;
144
145 raw_pixels_count_byte = cmd++; /* we'll know this later */
146 raw_pixel_start = pixel;
147
148 cmd_pixel_end = pixel + (min(MAX_CMD_PIXELS + 1,
149 min((int)(pixel_end - pixel) / bpp,
150 (int)(cmd_buffer_end - cmd) / 2))) * bpp;
151
152 prefetch_range((void *) pixel, (cmd_pixel_end - pixel) * bpp);
153
154 while (pixel < cmd_pixel_end) {
155 const u8 * const repeating_pixel = pixel;
156
157 if (bpp == 2)
158 *(uint16_t *)cmd = cpu_to_be16p((uint16_t *)pixel);
159 else if (bpp == 4)
160 *(uint16_t *)cmd = cpu_to_be16(pixel32_to_be16p(pixel));
161
162 cmd += 2;
163 pixel += bpp;
164
165 if (unlikely((pixel < cmd_pixel_end) &&
166 (!memcmp(pixel, repeating_pixel, bpp)))) {
167 /* go back and fill in raw pixel count */
168 *raw_pixels_count_byte = (((repeating_pixel -
169 raw_pixel_start) / bpp) + 1) & 0xFF;
170
171 while ((pixel < cmd_pixel_end)
172 && (!memcmp(pixel, repeating_pixel, bpp))) {
173 pixel += bpp;
174 }
175
176 /* immediately after raw data is repeat byte */
177 *cmd++ = (((pixel - repeating_pixel) / bpp) - 1) & 0xFF;
178
179 /* Then start another raw pixel span */
180 raw_pixel_start = pixel;
181 raw_pixels_count_byte = cmd++;
182 }
183 }
184
185 if (pixel > raw_pixel_start) {
186 /* finalize last RAW span */
187 *raw_pixels_count_byte = ((pixel-raw_pixel_start) / bpp) & 0xFF;
188 }
189
190 *cmd_pixels_count_byte = ((pixel - cmd_pixel_start) / bpp) & 0xFF;
191 dev_addr += ((pixel - cmd_pixel_start) / bpp) * 2;
192 }
193
194 if (cmd_buffer_end <= MIN_RLX_CMD_BYTES + cmd) {
195 /* Fill leftover bytes with no-ops */
196 if (cmd_buffer_end > cmd)
197 memset(cmd, 0xAF, cmd_buffer_end - cmd);
198 cmd = (uint8_t *) cmd_buffer_end;
199 }
200
201 *command_buffer_ptr = cmd;
202 *pixel_start_ptr = pixel;
203 *device_address_ptr = dev_addr;
204
205 return;
206}
207
208/*
209 * There are 3 copies of every pixel: The front buffer that the fbdev
210 * client renders to, the actual framebuffer across the USB bus in hardware
211 * (that we can only write to, slowly, and can never read), and (optionally)
212 * our shadow copy that tracks what's been sent to that hardware buffer.
213 */
214int udl_render_hline(struct drm_device *dev, int bpp, struct urb **urb_ptr,
215 const char *front, char **urb_buf_ptr,
216 u32 byte_offset, u32 byte_width,
217 int *ident_ptr, int *sent_ptr)
218{
219 const u8 *line_start, *line_end, *next_pixel;
220 u32 base16 = 0 + (byte_offset / bpp) * 2;
221 struct urb *urb = *urb_ptr;
222 u8 *cmd = *urb_buf_ptr;
223 u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
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, bpp);
234
235 if (cmd >= cmd_end) {
236 int len = cmd - (u8 *) urb->transfer_buffer;
237 if (udl_submit_urb(dev, urb, len))
238 return 1; /* lost pixels is set */
239 *sent_ptr += len;
240 urb = udl_get_urb(dev);
241 if (!urb)
242 return 1; /* lost_pixels is set */
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}
253