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From:   <alexandru.tachici@analog.com>
To:     <linux-hwmon@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <devicetree@vger.kernel.org>
CC:     <robh+dt@kernel.org>, <linux@roeck-us.net>,
        Alexandru Tachici <alexandru.tachici@analog.com>
Subject: [PATCH v6 7/9] hwmon: pmbus: adm1266: program firmware
Date:   Mon, 27 Jul 2020 08:31:19 +0300
Message-ID: <20200727053121.23288-8-alexandru.tachici@analog.com>
In-Reply-To: <20200727053121.23288-1-alexandru.tachici@analog.com>
References: <20200727053121.23288-1-alexandru.tachici@analog.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Alexandru Tachici <alexandru.tachici@analog.com>

Writing the firmware Intel hex file to the nvmem,
of the master adm1266,  with offset 0, will now
trigger the firmware programming of all cascaded
devices simultaneously through pmbus.

During this process all adm1266 sequencers will be
stopped and at the end will be issued a hard reset
(see AN-1453 Programming the firmware).

Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
---
 drivers/hwmon/pmbus/adm1266.c | 501 +++++++++++++++++++++++++++++++++-
 1 file changed, 500 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/pmbus/adm1266.c b/drivers/hwmon/pmbus/adm1266.c
index 34bd4e652729..376fc56abe04 100644
--- a/drivers/hwmon/pmbus/adm1266.c
+++ b/drivers/hwmon/pmbus/adm1266.c
@@ -9,6 +9,7 @@
 #include <linux/bitfield.h>
 #include <linux/crc8.h>
 #include <linux/debugfs.h>
+#include <linux/delay.h>
 #include <linux/gpio/driver.h>
 #include <linux/i2c.h>
 #include <linux/i2c-smbus.h>
@@ -18,18 +19,31 @@
 #include <linux/nvmem-consumer.h>
 #include <linux/nvmem-provider.h>
 #include "pmbus.h"
+#include <linux/property.h>
 #include <linux/slab.h>
 #include <linux/timekeeping.h>
 
+#define ADM1266_STORE_USER_ALL	0x15
+#define ADM1266_STATUS_MFR	0x80
+#define ADM1266_IC_DEVICE_REV	0xAE
 #define ADM1266_BLACKBOX_CONFIG	0xD3
 #define ADM1266_PDIO_CONFIG	0xD4
+#define ADM1266_SEQUENCE_CONFIG	0xD6
+#define ADM1266_SYSTEM_CONFIG	0xD7
+#define ADM1266_GO_COMMAND	0xD8
 #define ADM1266_READ_STATE	0xD9
 #define ADM1266_READ_BLACKBOX	0xDE
 #define ADM1266_SET_RTC		0xDF
+#define ADM1266_LOGIC_CONFIG	0xE0
 #define ADM1266_GPIO_CONFIG	0xE1
+#define ADM1266_USER_DATA	0xE3
 #define ADM1266_BLACKBOX_INFO	0xE6
 #define ADM1266_PDIO_STATUS	0xE9
 #define ADM1266_GPIO_STATUS	0xEA
+#define ADM1266_MEMORY_CONFIG	0xF8
+#define ADM1266_SWITCH_MEMORY	0xFA
+#define ADM1266_UPDATE_FW	0xFC
+#define ADM1266_FW_PASSWORD	0xFD
 
 /* ADM1266 GPIO defines */
 #define ADM1266_GPIO_NR			9
@@ -44,10 +58,35 @@
 #define ADM1266_PDIO_GLITCH_FILT(x)	FIELD_GET(GENMASK(12, 9), x)
 #define ADM1266_PDIO_OUT_CFG(x)		FIELD_GET(GENMASK(2, 0), x)
 
+/* ADM1266 FW_PASSWORD defines*/
+#define ADM1266_PASSWD_CMD_LEN	17
+#define ADM1266_CHANGE_PASSWORD	1
+#define ADM1266_UNLOCK_DEV	2
+#define ADM1266_LOCK_DEV	3
+
+/* ADM1266 STATUS_MFR defines */
+#define ADM1266_STATUS_PART_LOCKED(x)	FIELD_GET(BIT(2), x)
+
+/* ADM1266 GO_COMMAND defines */
+#define ADM1266_GO_COMMAND_STOP		BIT(0)
+#define ADM1266_GO_COMMAND_SEQ_RES	BIT(1)
+#define ADM1266_GO_COMMAND_HARD_RES	BIT(2)
+
+#define ADM1266_FIRMWARE_OFFSET		0x00000
+#define ADM1266_FIRMWARE_SIZE		131072
 #define ADM1266_BLACKBOX_OFFSET		0x7F700
 #define ADM1266_BLACKBOX_SIZE		64
 
 #define ADM1266_PMBUS_BLOCK_MAX		255
+#define ADM1266_MAX_DEVICES		16
+
+static LIST_HEAD(registered_masters);
+static DEFINE_MUTEX(registered_masters_lock);
+
+struct adm1266_data_ref {
+	struct adm1266_data *data;
+	struct list_head list;
+};
 
 struct adm1266_data {
 	struct pmbus_driver_info info;
@@ -57,6 +96,10 @@ struct adm1266_data {
 	struct dentry *debugfs_dir;
 	struct nvmem_config nvmem_config;
 	struct nvmem_device *nvmem;
+	bool master_dev;
+	struct list_head cascaded_devices_list;
+	struct mutex cascaded_devices_mutex; /* lock cascaded_devices_list */
+	u8 nr_devices;
 	u8 *dev_mem;
 	struct mutex buf_mutex;
 	u8 write_buf[ADM1266_PMBUS_BLOCK_MAX + 1] ____cacheline_aligned;
@@ -69,6 +112,11 @@ static const struct nvmem_cell_info adm1266_nvmem_cells[] = {
 		.offset         = ADM1266_BLACKBOX_OFFSET,
 		.bytes          = 2048,
 	},
+	{
+		.name           = "firmware",
+		.offset         = ADM1266_FIRMWARE_OFFSET,
+		.bytes          = ADM1266_FIRMWARE_SIZE,
+	},
 };
 
 DECLARE_CRC8_TABLE(pmbus_crc_table);
@@ -123,6 +171,27 @@ static int adm1266_pmbus_group_command(struct adm1266_data *data, struct i2c_cli
 	return ret;
 }
 
+static int adm1266_group_cmd(struct adm1266_data *data, u8 cmd, u8 *write_data, u8 w_len,
+			     bool to_slaves)
+{
+	struct i2c_client *clients[ADM1266_MAX_DEVICES];
+	struct adm1266_data_ref *slave_ref;
+	int i = 0;
+
+	clients[i] = data->client;
+	i++;
+
+	if (!to_slaves)
+		return adm1266_pmbus_group_command(data, clients, 1, cmd, w_len, write_data);
+
+	list_for_each_entry(slave_ref, &data->cascaded_devices_list, list) {
+		clients[i] = slave_ref->data->client;
+		i++;
+	}
+
+	return adm1266_pmbus_group_command(data, clients, i, cmd, w_len, write_data);
+}
+
 /*
  * Different from Block Read as it sends data and waits for the slave to
  * return a value dependent on that data. The protocol is simply a Write Block
@@ -449,6 +518,9 @@ static int adm1266_read_mem_cell(struct adm1266_data *data, const struct nvmem_c
 		if (ret)
 			dev_err(&data->client->dev, "Could not read blackbox!");
 		return ret;
+	case ADM1266_FIRMWARE_OFFSET:
+		/* firmware is write-only */
+		return 0;
 	default:
 		return -EINVAL;
 	}
@@ -477,14 +549,411 @@ static int adm1266_nvmem_read(void *priv, unsigned int offset, void *val,
 	return 0;
 }
 
+static int adm1266_unlock_device(struct adm1266_data *data)
+{
+	struct i2c_client *client = data->client;
+	u8 passwd_cmd[ADM1266_PASSWD_CMD_LEN];
+	int reg_val;
+	int ret;
+	int i;
+
+	memset(passwd_cmd, 0xFF, ADM1266_PASSWD_CMD_LEN);
+	passwd_cmd[ADM1266_PASSWD_CMD_LEN - 1] = ADM1266_UNLOCK_DEV;
+
+	/* password needs to be written twice correctly*/
+	for (i = 0; i < 2; i++) {
+		ret = i2c_smbus_write_block_data(client, ADM1266_FW_PASSWORD,
+						 ADM1266_PASSWD_CMD_LEN, passwd_cmd);
+		if (ret < 0) {
+			dev_err(&client->dev, "Could not write password.");
+			return ret;
+		}
+
+		/* 50 ms delay between subsequent password writes are needed*/
+		msleep(50);
+	}
+
+	/* check if device is unlocked */
+	reg_val = pmbus_read_byte_data(client, 0, ADM1266_STATUS_MFR);
+	if (reg_val < 0) {
+		dev_err(&client->dev, "Could not read status.");
+		return reg_val;
+	}
+	if (ADM1266_STATUS_PART_LOCKED(reg_val)) {
+		dev_err(&client->dev, "Device locked.");
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
+static int adm1266_unlock_all_dev(struct adm1266_data *data)
+{
+	struct adm1266_data_ref *slave_ref;
+	int ret;
+
+	ret = adm1266_unlock_device(data);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Could not unlock master.");
+		return ret;
+	}
+
+	list_for_each_entry(slave_ref, &data->cascaded_devices_list, list) {
+		ret = adm1266_unlock_device(slave_ref->data);
+		if (ret < 0) {
+			dev_err(&data->client->dev, "Could not unlock slave addr: %d.",
+				slave_ref->data->client->addr);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int adm1266_lock_device(struct adm1266_data *data)
+{
+	struct i2c_client *client = data->client;
+	u8 passwd_cmd[ADM1266_PASSWD_CMD_LEN];
+	int reg_val;
+	int ret;
+
+	memset(passwd_cmd, 0, ADM1266_PASSWD_CMD_LEN);
+	passwd_cmd[ADM1266_PASSWD_CMD_LEN - 1] = ADM1266_LOCK_DEV;
+
+	ret = i2c_smbus_write_block_data(client, ADM1266_FW_PASSWORD, ADM1266_PASSWD_CMD_LEN,
+					 passwd_cmd);
+	if (ret < 0)
+		return ret;
+
+	msleep(50);
+
+	/* check if device is now locked */
+	reg_val = pmbus_read_byte_data(client, 0, ADM1266_STATUS_MFR);
+	if (reg_val < 0)
+		return reg_val;
+
+	if (!ADM1266_STATUS_PART_LOCKED(reg_val))
+		return -EBUSY;
+
+	return 0;
+}
+
+static void adm1266_lock_all_dev(struct adm1266_data *data)
+{
+	struct adm1266_data_ref *slave_ref;
+	int ret;
+
+	ret = adm1266_lock_device(data);
+	if (ret < 0)
+		dev_warn(&data->client->dev, "Could not lock dev: %s.",
+			 dev_name(&data->client->dev));
+
+	list_for_each_entry(slave_ref, &data->cascaded_devices_list, list) {
+		ret = adm1266_lock_device(slave_ref->data);
+		if (ret < 0)
+			dev_warn(&slave_ref->data->client->dev, "Could not lock dev: %s.",
+				 dev_name(&slave_ref->data->client->dev));
+	}
+}
+
+static const int write_delays[][3] = {
+	{ADM1266_SYSTEM_CONFIG, 400, 1},
+	{ADM1266_USER_DATA, 100, 1},
+	{ADM1266_LOGIC_CONFIG, 200, 1},
+	{ADM1266_SEQUENCE_CONFIG, 2500, 1},
+	{ADM1266_UPDATE_FW, 2000, 1},
+	{ADM1266_MEMORY_CONFIG, 100, 0},
+	{ADM1266_STORE_USER_ALL, 300, 0},
+};
+
+static int adm1266_write_hex(struct adm1266_data *data,
+			     unsigned int offset, unsigned int size)
+{
+	const u8 *ending_str = ":00000001FF";
+	u8 *hex_cmd = data->dev_mem + offset;
+	u8 *fw_end = data->dev_mem + offset + size;
+	unsigned int write_delay;
+	u8 write_buf[ADM1266_PMBUS_BLOCK_MAX + 1];
+	u8 first_writes[7];
+	u8 byte_count;
+	u8 reg_address;
+	int ret;
+	int i;
+
+	memset(first_writes, 1, 7);
+
+	while (hex_cmd < fw_end) {
+		hex_cmd = strnchr(hex_cmd, size, ':');
+
+		if (!hex_cmd || hex_cmd >= fw_end) {
+			dev_err(&data->client->dev, "Firmware ending missing.");
+			return -EINVAL;
+		}
+
+		if (!strncmp(hex_cmd, ending_str, strlen(ending_str)))
+			break;
+
+		hex_cmd++;
+
+		ret = hex2bin(&byte_count, hex_cmd, 1);
+		if (ret < 0)
+			return ret;
+
+		ret = hex2bin(&reg_address, hex_cmd + 4, 1);
+		if (ret < 0)
+			return ret;
+
+		ret = hex2bin(write_buf, hex_cmd + 8, byte_count);
+		if (ret < 0)
+			return ret;
+
+		ret = adm1266_group_cmd(data, reg_address, write_buf, byte_count, true);
+		if (ret < 0) {
+			dev_err(&data->client->dev, "Firmware write error: %d.", ret);
+			return ret;
+		}
+
+		/* write to eeprom with specified delays */
+		write_delay = 40;
+		for (i = 0; i < 7; i++) {
+			if (reg_address == write_delays[i][0]) {
+				if (write_delays[i][2] && first_writes[i]) {
+					first_writes[i] = 0;
+					write_delay = write_delays[i][1];
+				}
+
+				if (!write_delays[i][2])
+					write_delay = write_delays[i][1];
+			}
+		}
+		msleep(write_delay);
+	}
+
+	return 0;
+}
+
+static int adm1266_program_firmware(struct adm1266_data *data)
+{
+	u8 write_data[3];
+	int ret;
+
+	write_data[0] = ADM1266_GO_COMMAND_STOP | ADM1266_GO_COMMAND_SEQ_RES;
+	write_data[1] = 0x0;
+	ret = adm1266_group_cmd(data, ADM1266_GO_COMMAND, write_data, 2, true);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Could not stop all devs.");
+		return ret;
+	}
+
+	/* after issuing a stop command, wait 100 ms */
+	msleep(100);
+
+	ret = adm1266_unlock_all_dev(data);
+	if (ret < 0)
+		goto lock_all_devices;
+
+	write_data[0] = 0x2;
+	write_data[1] = 0x0;
+	write_data[2] = 0x0;
+	ret = adm1266_group_cmd(data, ADM1266_UPDATE_FW, write_data, 3, true);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Could not set bootloader mode.");
+		goto lock_all_devices;
+	}
+
+	/* wait for adm1266 to enter bootloader mode */
+	msleep(2000);
+
+	ret = adm1266_write_hex(data, ADM1266_FIRMWARE_OFFSET,
+				ADM1266_FIRMWARE_SIZE);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Could not write hex.");
+		goto lock_all_devices;
+	}
+
+	write_data[0] = ADM1266_GO_COMMAND_HARD_RES;
+	ret = adm1266_group_cmd(data, ADM1266_GO_COMMAND, write_data, 2, true);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Could not reset all devs.");
+		goto lock_all_devices;
+	}
+
+lock_all_devices:
+	adm1266_lock_all_dev(data);
+
+	return ret;
+}
+
+/* check if firmware/config write has ended */
+static bool adm1266_check_ending(struct adm1266_data *data, unsigned int offset,
+				 unsigned int size)
+{
+	const u8 *ending_str = ":00000001FF";
+	u8 *hex_cmd = data->dev_mem + offset;
+	u8 *fw_end = data->dev_mem + offset + size;
+
+	hex_cmd = strnchr(hex_cmd, size, ':');
+	for (; hex_cmd && hex_cmd < fw_end;
+	     hex_cmd = strnchr(hex_cmd, size, ':')) {
+		if (!strncmp(hex_cmd, ending_str, strlen(ending_str)))
+			return true;
+
+		hex_cmd++;
+	}
+
+	return false;
+}
+
+static int adm1266_write_mem_cell(struct adm1266_data *data,
+				  const struct nvmem_cell_info *mem_cell,
+				  unsigned int offset,
+				  u8 *val,
+				  size_t bytes)
+{
+	unsigned int cell_end = mem_cell->offset + mem_cell->bytes;
+	unsigned int cell_start = mem_cell->offset;
+	int (*program_func)(struct adm1266_data *data);
+	bool fw_writen;
+
+	switch (mem_cell->offset) {
+	case ADM1266_FIRMWARE_OFFSET:
+		if (!data->master_dev) {
+			dev_err(&data->client->dev,
+				"Only master programs the firmware.");
+			return -EINVAL;
+		}
+
+		program_func = &adm1266_program_firmware;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (offset < cell_start || offset + bytes >= cell_end)
+		return -EINVAL;
+
+	if (offset == mem_cell->offset)
+		memset(data->dev_mem + mem_cell->offset, 0, mem_cell->bytes);
+
+	memcpy(data->dev_mem + offset, val, bytes);
+
+	fw_writen = adm1266_check_ending(data, mem_cell->offset,
+					 mem_cell->bytes);
+
+	if (fw_writen)
+		return program_func(data);
+
+	return 0;
+}
+
+static int adm1266_nvmem_write(void *priv, unsigned int offset, void *val,
+			       size_t bytes)
+{
+	const struct nvmem_cell_info *mem_cell;
+	struct adm1266_data *data = priv;
+	int ret;
+	int i;
+
+	for (i = 0; i < data->nvmem_config.ncells; i++) {
+		mem_cell = &adm1266_nvmem_cells[i];
+
+		if (!adm1266_cell_is_accessed(mem_cell, offset, bytes))
+			continue;
+
+		ret = adm1266_write_mem_cell(data, mem_cell, offset,
+					     val, bytes);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int adm1266_register_slave(struct adm1266_data *slave,
+				  struct adm1266_data *master)
+{
+	struct adm1266_data_ref *slave_ref;
+
+	slave_ref = devm_kzalloc(&slave->client->dev,
+				 sizeof(*slave_ref), GFP_KERNEL);
+	if (!slave_ref)
+		return -ENOMEM;
+
+	slave_ref->data = slave;
+	INIT_LIST_HEAD(&slave_ref->list);
+
+	mutex_lock(&master->cascaded_devices_mutex);
+	list_add_tail(&slave_ref->list, &master->cascaded_devices_list);
+	mutex_unlock(&master->cascaded_devices_mutex);
+
+	return 0;
+}
+
+static int adm1266_register(struct adm1266_data *data)
+{
+	struct fwnode_reference_args master_fwnode_ref;
+	const struct fwnode_handle *fw;
+	const struct fwnode_handle *master_fw;
+	struct adm1266_data_ref *master_ref;
+	int ret;
+
+	fw = dev_fwnode(&data->client->dev);
+	INIT_LIST_HEAD(&data->cascaded_devices_list);
+
+	/* master devices do not have this property */
+	if (!fwnode_property_present(fw, "adi,master-adm1266")) {
+		data->master_dev = true;
+
+		master_ref = devm_kzalloc(&data->client->dev,
+					  sizeof(*master_ref), GFP_KERNEL);
+		if (!master_ref)
+			return -ENOMEM;
+
+		master_ref->data = data;
+		INIT_LIST_HEAD(&master_ref->list);
+
+		mutex_lock(&registered_masters_lock);
+		list_add(&master_ref->list, &registered_masters);
+		mutex_unlock(&registered_masters_lock);
+	}
+
+	if (data->master_dev)
+		return 0;
+
+	ret = fwnode_property_get_reference_args(fw, "adi,master-adm1266",
+						 NULL, 0, 0,
+						 &master_fwnode_ref);
+	if (ret < 0) {
+		dev_err(&data->client->dev,
+			"Could not read adi,master-adm1266 property");
+		return ret;
+	}
+
+	mutex_lock(&registered_masters_lock);
+
+	/* search for the corresponding master of this slave */
+	list_for_each_entry(master_ref, &registered_masters, list) {
+		master_fw = dev_fwnode(&master_ref->data->client->dev);
+
+		if (master_fw == master_fwnode_ref.fwnode) {
+			mutex_unlock(&registered_masters_lock);
+			return adm1266_register_slave(data, master_ref->data);
+		}
+	}
+
+	mutex_unlock(&registered_masters_lock);
+
+	return -EPROBE_DEFER;
+}
+
 static int adm1266_config_nvmem(struct adm1266_data *data)
 {
 	data->nvmem_config.name = dev_name(&data->client->dev);
 	data->nvmem_config.dev = &data->client->dev;
 	data->nvmem_config.root_only = true;
-	data->nvmem_config.read_only = true;
 	data->nvmem_config.owner = THIS_MODULE;
 	data->nvmem_config.reg_read = adm1266_nvmem_read;
+	data->nvmem_config.reg_write = adm1266_nvmem_write;
 	data->nvmem_config.cells = adm1266_nvmem_cells;
 	data->nvmem_config.ncells = ARRAY_SIZE(adm1266_nvmem_cells);
 	data->nvmem_config.priv = data;
@@ -528,6 +997,21 @@ static int adm1266_set_rtc(struct adm1266_data *data)
 					  write_buf);
 }
 
+static int adm1266_firmware_present(struct i2c_client *client)
+{
+	u8 read_buf[I2C_SMBUS_BLOCK_MAX];
+	int ret;
+
+	ret = i2c_smbus_read_i2c_block_data(client, ADM1266_IC_DEVICE_REV,
+					    8, read_buf);
+	if (ret < 0) {
+		dev_err(&client->dev, "Could not read firmware revision.");
+		return ret;
+	}
+
+	return !!(read_buf[0] | read_buf[1] | read_buf[2]);
+}
+
 static int adm1266_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
 	struct adm1266_data *data;
@@ -546,6 +1030,21 @@ static int adm1266_probe(struct i2c_client *client, const struct i2c_device_id *
 
 	crc8_populate_msb(pmbus_crc_table, 0x7);
 	mutex_init(&data->buf_mutex);
+	mutex_init(&data->cascaded_devices_mutex);
+
+	ret = adm1266_register(data);
+	if (ret < 0)
+		return ret;
+
+	ret = adm1266_firmware_present(client);
+	if (ret < 0)
+		return ret;
+
+	if (!ret) {
+		dev_notice(&client->dev, "Chip firmware not written.");
+		return adm1266_config_nvmem(data);
+	}
+
 
 	ret = adm1266_config_gpio(data);
 	if (ret < 0)
-- 
2.20.1