From fe46d2a4301de1299fb32c0317ec316706ceaad6 Mon Sep 17 00:00:00 2001 From: Pierre-Louis Bossart Date: Mon, 3 Jun 2024 14:58:40 +0800 Subject: [PATCH] soundwire: debugfs: add interface to read/write commands We have an existing debugfs files to read standard registers (DP0/SCP/DPn). This patch provides a more generic interface to ANY set of read/write contiguous registers in a peripheral device. In follow-up patches, this interface will be extended to use BRA transfers. The sequence is to use the following files added under the existing debugsfs directory for each peripheral device: command (write 0, read 1) num_bytes start_address firmware_file (only for writes) read_buffer (only for reads) Example for a read command - this checks the 6 bytes used for enumeration. cd /sys/kernel/debug/soundwire/master-0-0/sdw\:0\:025d\:0711\:01/ echo 1 > command echo 6 > num_bytes echo 0x50 > start_address echo 1 > go cat read_buffer address 0x50 val 0x30 address 0x51 val 0x02 address 0x52 val 0x5d address 0x53 val 0x07 address 0x54 val 0x11 address 0x55 val 0x01 Example with a 2-byte firmware file written in DP0 address 0x22 od -x /lib/firmware/test_firmware 0000000 0a37 0000002 cd /sys/kernel/debug/soundwire/master-0-0/sdw\:0\:025d\:0711\:01/ echo 0 > command echo 2 > num_bytes echo 0x22 > start_address echo "test_firmware" > firmware_file echo 1 > go cd /sys/kernel/debug/soundwire/master-0-0/sdw\:0\:025d\:0711\:01/ echo 1 > command echo 2 > num_bytes echo 0x22 > start_address echo 1 > go cat read_buffer address 0x22 val 0x37 address 0x23 val 0x0a Signed-off-by: Pierre-Louis Bossart Reviewed-by: Rander Wang Signed-off-by: Bard Liao Link: https://lore.kernel.org/r/20240603065841.4860-1-yung-chuan.liao@linux.intel.com Signed-off-by: Vinod Koul --- drivers/soundwire/debugfs.c | 150 ++++++++++++++++++++++++++++++++++++ 1 file changed, 150 insertions(+) diff --git a/drivers/soundwire/debugfs.c b/drivers/soundwire/debugfs.c index 67abd7e52f09..6d253d69871d 100644 --- a/drivers/soundwire/debugfs.c +++ b/drivers/soundwire/debugfs.c @@ -3,6 +3,7 @@ #include #include +#include #include #include #include @@ -137,6 +138,145 @@ static int sdw_slave_reg_show(struct seq_file *s_file, void *data) } DEFINE_SHOW_ATTRIBUTE(sdw_slave_reg); +#define MAX_CMD_BYTES 256 + +static int cmd; +static u32 start_addr; +static size_t num_bytes; +static u8 read_buffer[MAX_CMD_BYTES]; +static char *firmware_file; + +static int set_command(void *data, u64 value) +{ + struct sdw_slave *slave = data; + + if (value > 1) + return -EINVAL; + + /* Userspace changed the hardware state behind the kernel's back */ + add_taint(TAINT_USER, LOCKDEP_STILL_OK); + + dev_dbg(&slave->dev, "command: %s\n", value ? "read" : "write"); + cmd = value; + + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(set_command_fops, NULL, + set_command, "%llu\n"); + +static int set_start_address(void *data, u64 value) +{ + struct sdw_slave *slave = data; + + /* Userspace changed the hardware state behind the kernel's back */ + add_taint(TAINT_USER, LOCKDEP_STILL_OK); + + dev_dbg(&slave->dev, "start address %#llx\n", value); + + start_addr = value; + + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(set_start_address_fops, NULL, + set_start_address, "%llu\n"); + +static int set_num_bytes(void *data, u64 value) +{ + struct sdw_slave *slave = data; + + if (value == 0 || value > MAX_CMD_BYTES) + return -EINVAL; + + /* Userspace changed the hardware state behind the kernel's back */ + add_taint(TAINT_USER, LOCKDEP_STILL_OK); + + dev_dbg(&slave->dev, "number of bytes %lld\n", value); + + num_bytes = value; + + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(set_num_bytes_fops, NULL, + set_num_bytes, "%llu\n"); + +static int cmd_go(void *data, u64 value) +{ + struct sdw_slave *slave = data; + int ret; + + if (value != 1) + return -EINVAL; + + /* one last check */ + if (start_addr > SDW_REG_MAX || + num_bytes == 0 || num_bytes > MAX_CMD_BYTES) + return -EINVAL; + + ret = pm_runtime_get_sync(&slave->dev); + if (ret < 0 && ret != -EACCES) { + pm_runtime_put_noidle(&slave->dev); + return ret; + } + + /* Userspace changed the hardware state behind the kernel's back */ + add_taint(TAINT_USER, LOCKDEP_STILL_OK); + + dev_dbg(&slave->dev, "starting command\n"); + + if (cmd == 0) { + const struct firmware *fw; + + ret = request_firmware(&fw, firmware_file, &slave->dev); + if (ret < 0) { + dev_err(&slave->dev, "firmware %s not found\n", firmware_file); + goto out; + } + + if (fw->size != num_bytes) { + dev_err(&slave->dev, + "firmware %s: unexpected size %zd, desired %zd\n", + firmware_file, fw->size, num_bytes); + release_firmware(fw); + goto out; + } + + ret = sdw_nwrite_no_pm(slave, start_addr, num_bytes, fw->data); + release_firmware(fw); + } else { + ret = sdw_nread_no_pm(slave, start_addr, num_bytes, read_buffer); + } + + dev_dbg(&slave->dev, "command completed %d\n", ret); + +out: + pm_runtime_mark_last_busy(&slave->dev); + pm_runtime_put(&slave->dev); + + return ret; +} +DEFINE_DEBUGFS_ATTRIBUTE(cmd_go_fops, NULL, + cmd_go, "%llu\n"); + +#define MAX_LINE_LEN 128 + +static int read_buffer_show(struct seq_file *s_file, void *data) +{ + char buf[MAX_LINE_LEN]; + int i; + + if (num_bytes == 0 || num_bytes > MAX_CMD_BYTES) + return -EINVAL; + + for (i = 0; i < num_bytes; i++) { + scnprintf(buf, MAX_LINE_LEN, "address %#x val 0x%02x\n", + start_addr + i, read_buffer[i]); + seq_printf(s_file, "%s", buf); + } + + return 0; +} +DEFINE_SHOW_ATTRIBUTE(read_buffer); + void sdw_slave_debugfs_init(struct sdw_slave *slave) { struct dentry *master; @@ -151,6 +291,16 @@ void sdw_slave_debugfs_init(struct sdw_slave *slave) debugfs_create_file("registers", 0400, d, slave, &sdw_slave_reg_fops); + /* interface to send arbitrary commands */ + debugfs_create_file("command", 0200, d, slave, &set_command_fops); + debugfs_create_file("start_address", 0200, d, slave, &set_start_address_fops); + debugfs_create_file("num_bytes", 0200, d, slave, &set_num_bytes_fops); + debugfs_create_file("go", 0200, d, slave, &cmd_go_fops); + + debugfs_create_file("read_buffer", 0400, d, slave, &read_buffer_fops); + firmware_file = NULL; + debugfs_create_str("firmware_file", 0200, d, &firmware_file); + slave->debugfs = d; }