[igt-dev] [PATCH i-g-t v5] tools: Add a simple tool to read/write/decode dpcd registers
Tarun Vyas
tarun.vyas at intel.com
Thu Oct 4 18:16:18 UTC 2018
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:
- Addres 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 <dhinakaran.pandiyan at intel.com>
Signed-off-by: Tarun Vyas <tarun.vyas at intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
---
tools/Makefile.sources | 1 +
tools/dpcd_reg.c | 274 +++++++++++++++++++++++++++++++++++++++++++++++++
tools/meson.build | 1 +
3 files changed, 276 insertions(+)
create mode 100644 tools/dpcd_reg.c
diff --git a/tools/Makefile.sources b/tools/Makefile.sources
index abd23a0f..50706f41 100644
--- a/tools/Makefile.sources
+++ b/tools/Makefile.sources
@@ -7,6 +7,7 @@ noinst_PROGRAMS = \
tools_prog_lists = \
igt_stats \
+ dpcd_reg \
intel_audio_dump \
intel_reg \
intel_backlight \
diff --git a/tools/dpcd_reg.c b/tools/dpcd_reg.c
new file mode 100644
index 00000000..02e51214
--- /dev/null
+++ b/tools/dpcd_reg.c
@@ -0,0 +1,274 @@
+/*
+ * 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, "--devid 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,
+ };
+
+ if((ret = parse_opts(&dpcd, argc, argv)) != 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;
+}
diff --git a/tools/meson.build b/tools/meson.build
index e4517d66..79f36aa9 100644
--- a/tools/meson.build
+++ b/tools/meson.build
@@ -36,6 +36,7 @@ tools_progs = [
'intel_watermark',
'intel_gem_info',
'intel_gvtg_test',
+ 'dpcd_reg',
]
tool_deps = igt_deps
--
2.14.1
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