Commit 7e066794 authored by Tarun Vyas's avatar Tarun Vyas Committed by Dhinakaran Pandiyan

tools: Add a simple tool to read/write/decode dpcd registers

This tool serves as a wrapper around the constructs provided by the
drm_dpcd_aux_dev kernel module by working on the /dev/drm_dp_aux[n]
devices created by the kernel module.
It supports reading and writing dpcd registers on the connected aux
channels.
In the follow-up patch, support for decoding these registers will be
added to facilate debugging panel related issues.

v2: (Fixes by Rodrigo but no functional changes yet):
    - Indentations, Typo, Missed spaces
    - Removing mentioning to decode and spec that is not implemented yet.
    - Add Makefile.sources back
    - Missed s/printf/igt_warn

v3:
    - Address DK's review comments from v2 above.
    - Squash Rodrigo's file handling unification patch.
    - Make count, offset and device id optional.

v4:
    - Better error handling and refactoring.
Suggested-by: Dhinakaran Pandiyan's avatarDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: default avatarTarun Vyas <tarun.vyas@intel.com>
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Dhinakaran Pandiyan's avatarDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
parent 5f40e617
......@@ -7,6 +7,7 @@ noinst_PROGRAMS = \
tools_prog_lists = \
igt_stats \
dpcd_reg \
intel_audio_dump \
intel_reg \
intel_backlight \
......
/*
* Copyright © 2018 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* DPCD register read/write tool
* This tool wraps around DRM_DP_AUX_DEV module to provide DPCD register read
* and write, so CONFIG_DRM_DP_AUX_DEV needs to be set.
*/
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <getopt.h>
#include <stdint.h>
#include <unistd.h>
#include <limits.h>
#include <stdbool.h>
#define MAX_DP_OFFSET 0xfffff
#define DRM_AUX_MINORS 256
const char aux_dev[] = "/dev/drm_dp_aux";
struct dpcd_data {
int devid;
int file_op;
uint32_t offset;
enum command {
INVALID = -1,
READ = 2,
WRITE,
} cmd;
size_t count;
uint8_t val;
};
static void print_usage(void)
{
printf("Usage: dpcd_reg [OPTION ...] COMMAND\n\n");
printf("COMMAND is one of:\n");
printf(" read: Read [count] bytes dpcd reg at an offset\n");
printf(" write: Write a dpcd reg at an offset\n\n");
printf("Options for the above COMMANDS are\n");
printf(" --device=DEVID Aux device id, as listed in /dev/drm_dp_aux_dev[n]. Defaults to 0. Upper limit - 256\n");
printf(" --offset=REG_ADDR DPCD register offset in hex. Defaults to 0x0. Upper limit - 0xfffff\n");
printf(" --count=BYTES For reads, specify number of bytes to be read from the offset. Defaults to 1\n");
printf(" --value For writes, specify a hex value to be written. Upper limit - 0xff\n\n");
printf(" --help: print the usage\n");
}
static inline bool strtol_err_util(char *endptr, long *val)
{
if (*endptr != '\0' || *val < 0 ||
(*val == LONG_MAX && errno == ERANGE))
return true;
return false;
}
static int parse_opts(struct dpcd_data *dpcd, int argc, char **argv)
{
int ret, vflag = 0;
long temp;
char *endptr;
struct option longopts[] = {
{ "count", required_argument, NULL, 'c' },
{ "device", required_argument, NULL, 'd' },
{ "help", no_argument, NULL, 'h' },
{ "offset", required_argument, NULL, 'o' },
{ "value", required_argument, NULL, 'v' },
{ 0 }
};
while ((ret = getopt_long(argc, argv, "-:c:d:ho:v:", longopts, NULL)) != -1) {
switch (ret) {
case 'c':
temp = strtol(optarg, &endptr, 10);
if (strtol_err_util(endptr, &temp)) {
fprintf(stderr,
"--count argument is invalid/negative/out-of-range\n");
print_usage();
return EXIT_FAILURE;
}
dpcd->count = temp;
break;
case 'd':
temp = strtol(optarg, &endptr, 10);
if (strtol_err_util(endptr, &temp) ||
temp > DRM_AUX_MINORS) {
fprintf(stderr,
"--device argument is invalid/negative/out-of-range\n");
print_usage();
return ERANGE;
}
dpcd->devid = temp;
break;
case 'h':
printf("DPCD register read and write tool\n\n");
printf("This tool requires CONFIG_DRM_DP_AUX_CHARDEV\n"
"to be set in the kernel config.\n\n");
print_usage();
exit(EXIT_SUCCESS);
case 'o':
temp = strtol(optarg, &endptr, 16);
if (strtol_err_util(endptr, &temp) ||
temp > MAX_DP_OFFSET) {
fprintf(stderr,
"--offset argument is invalid/negative/out-of-range\n");
print_usage();
return ERANGE;
}
dpcd->offset = temp;
break;
case 'v':
vflag = 'v';
temp = strtol(optarg, &endptr, 16);
if (strtol_err_util(endptr, &temp) || temp > 0xff) {
fprintf(stderr,
"--value argument is invalid/negative/out-of-range\n");
print_usage();
return ERANGE;
}
dpcd->val = temp;
break;
/* Command parsing */
case 1:
if (strcmp(optarg, "read") == 0) {
temp = READ;
} else if (strcmp(optarg, "write") == 0) {
temp = WRITE;
dpcd->file_op = O_WRONLY;
} else {
fprintf(stderr, "Unrecognized command\n");
print_usage();
return EXIT_FAILURE;
}
dpcd->cmd = temp;
break;
case ':':
fprintf(stderr, "Option -%c requires an argument\n",
optopt);
print_usage();
return EXIT_FAILURE;
default:
fprintf(stderr, "Invalid option\n");
print_usage();
return EXIT_FAILURE;
}
}
if ((dpcd->count + dpcd->offset) > (MAX_DP_OFFSET + 1)) {
fprintf(stderr, "Out of bounds. Count + Offset <= 0x100000\n");
return ERANGE;
}
if ((dpcd->cmd == WRITE) && (vflag != 'v')) {
fprintf(stderr, "Write value is missing\n");
print_usage();
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
static int dpcd_read(int fd, uint32_t offset, size_t count)
{
int ret = EXIT_SUCCESS, pret, i;
uint8_t *buf = calloc(count, sizeof(uint8_t));
if (!buf) {
fprintf(stderr, "Can't allocate read buffer\n");
return ENOMEM;
}
pret = pread(fd, buf, count, offset);
if (pret < 0) {
fprintf(stderr, "Failed to read - %s\n", strerror(errno));
ret = errno;
goto out;
}
if (pret < count) {
fprintf(stderr,
"Read %u byte(s), expected %zu bytes, starting at offset %x\n\n", pret, count, offset);
ret = EXIT_FAILURE;
}
printf("0x%02x: ", offset);
for (i = 0; i < pret; i++)
printf(" %02x", *(buf + i));
printf("\n");
out:
free(buf);
return ret;
}
static int dpcd_write(int fd, uint32_t offset, uint8_t val)
{
int ret = EXIT_SUCCESS, pret;
pret = pwrite(fd, (const void *)&val, sizeof(uint8_t), offset);
if (pret < 0) {
fprintf(stderr, "Failed to write - %s\n", strerror(errno));
ret = errno;
} else if (pret == 0) {
fprintf(stderr, "Zero bytes were written\n");
ret = EXIT_FAILURE;
}
return ret;
}
int main(int argc, char **argv)
{
char dev_name[20];
int ret, fd;
struct dpcd_data dpcd = {
.devid = 0,
.file_op = O_RDONLY,
.offset = 0x0,
.cmd = INVALID,
.count = 1,
};
ret = parse_opts(&dpcd, argc, argv);
if (ret != EXIT_SUCCESS)
return ret;
snprintf(dev_name, strlen(aux_dev) + 4, "%s%d", aux_dev, dpcd.devid);
fd = open(dev_name, dpcd.file_op);
if (fd < 0) {
fprintf(stderr,
"Failed to open %s aux device - error: %s\n", dev_name,
strerror(errno));
return errno;
}
switch (dpcd.cmd) {
case READ:
ret = dpcd_read(fd, dpcd.offset, dpcd.count);
break;
case WRITE:
ret = dpcd_write(fd, dpcd.offset, dpcd.val);
break;
default:
fprintf(stderr, "Please specify a command: read/write.\n");
print_usage();
ret = EXIT_FAILURE;
break;
}
close(fd);
return ret;
}
......@@ -36,6 +36,7 @@ tools_progs = [
'intel_watermark',
'intel_gem_info',
'intel_gvtg_test',
'dpcd_reg',
]
tool_deps = igt_deps
......
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