Commit fe46d2a4 authored by Pierre-Louis Bossart's avatar Pierre-Louis Bossart Committed by Vinod Koul
Browse files

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: default avatarPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: default avatarRander Wang <rander.wang@intel.com>
Signed-off-by: default avatarBard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20240603065841.4860-1-yung-chuan.liao@linux.intel.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 1613e604

drivers/soundwire/debugfs.c

+150 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 


#include <linux/device.h>

#include <linux/debugfs.h>

#include <linux/firmware.h>

#include <linux/mod_devicetable.h>

#include <linux/pm_runtime.h>

#include <linux/slab.h>
@@ -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;

}