// SPDX-License-Identifier: GPL-2.0
#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/fsi-sbefifo.h>
#include <linux/gfp.h>
#include <linux/idr.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/miscdevice.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/fsi-occ.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/unaligned.h>
#define OCC_SRAM_BYTES 4096
#define OCC_CMD_DATA_BYTES 4090
#define OCC_RESP_DATA_BYTES 4089
#define OCC_P9_SRAM_CMD_ADDR 0xFFFBE000
#define OCC_P9_SRAM_RSP_ADDR 0xFFFBF000
#define OCC_P10_SRAM_CMD_ADDR 0xFFFFD000
#define OCC_P10_SRAM_RSP_ADDR 0xFFFFE000
#define OCC_P10_SRAM_MODE 0x58 /* Normal mode, OCB channel 2 */
#define OCC_TIMEOUT_MS 1000
#define OCC_CMD_IN_PRG_WAIT_MS 50
enum versions { occ_p9, occ_p10 };
struct occ {
struct device *dev;
struct device *sbefifo;
char name[32];
int idx;
bool platform_hwmon;
u8 sequence_number;
void *buffer;
void *client_buffer;
size_t client_buffer_size;
size_t client_response_size;
enum versions version;
struct miscdevice mdev;
struct mutex occ_lock;
};
#define to_occ(x) container_of((x), struct occ, mdev)
struct occ_response {
u8 seq_no;
u8 cmd_type;
u8 return_status;
__be16 data_length;
u8 data[OCC_RESP_DATA_BYTES + 2]; /* two bytes checksum */
} __packed;
struct occ_client {
struct occ *occ;
struct mutex lock;
size_t data_size;
size_t read_offset;
u8 *buffer;
};
#define to_client(x) container_of((x), struct occ_client, xfr)
static DEFINE_IDA(occ_ida);
static int occ_open(struct inode *inode, struct file *file)
{
struct occ_client *client = kzalloc(sizeof(*client), GFP_KERNEL);
struct miscdevice *mdev = file->private_data;
struct occ *occ = to_occ(mdev);
if (!client)
return -ENOMEM;
client->buffer = (u8 *)__get_free_page(GFP_KERNEL);
if (!client->buffer) {
kfree(client);
return -ENOMEM;
}
client->occ = occ;
mutex_init(&client->lock);
file->private_data = client;
get_device(occ->dev);
/* We allocate a 1-page buffer, make sure it all fits */
BUILD_BUG_ON((OCC_CMD_DATA_BYTES + 3) > PAGE_SIZE);
BUILD_BUG_ON((OCC_RESP_DATA_BYTES + 7) > PAGE_SIZE);
return 0;
}
static ssize_t occ_read(struct file *file, char __user *buf, size_t len,
loff_t *offset)
{
struct occ_client *client = file->private_data;
ssize_t rc = 0;
if (!client)
return -ENODEV;
if (len > OCC_SRAM_BYTES)
return -EINVAL;
mutex_lock(&client->lock);
/* This should not be possible ... */
if (WARN_ON_ONCE(client->read_offset > client->data_size)) {
rc = -EIO;
goto done;
}
/* Grab how much data we have to read */
rc = min(len, client->data_size - client->read_offset);
if (copy_to_user(buf, client->buffer + client->read_offset, rc))
rc = -EFAULT;
else
client->read_offset += rc;
done:
mutex_unlock(&client->lock);
return rc;
}
static ssize_t occ_write(struct file *file, const char __user *buf,
size_t len, loff_t *offset)
{
struct occ_client *client = file->private_data;
size_t rlen, data_length;
ssize_t rc;
u8 *cmd;
if (!client)
return -ENODEV;
if (len > (OCC_CMD_DATA_BYTES + 3) || len < 3)
return -EINVAL;
mutex_lock(&client->lock);
/* Construct the command */
cmd = client->buffer;
/*
* Copy the user command (assume user data follows the occ command
* format)
* byte 0: command type
* bytes 1-2: data length (msb first)
* bytes 3-n: data
*/
if (copy_from_user(&cmd[1], buf, len)) {
rc = -EFAULT;
goto done;
}
/* Extract data length */
data_length = (cmd[2] << 8) + cmd[3];
if (data_length > OCC_CMD_DATA_BYTES) {
rc = -EINVAL;
goto done;
}
/* Submit command; 4 bytes before the data and 2 bytes after */
rlen = PAGE_SIZE;
rc = fsi_occ_submit(client->occ->dev, cmd, data_length + 6, cmd,
&rlen);
if (rc)
goto done;
/* Set read tracking data */
client->data_size = rlen;
client->read_offset = 0;
/* Done */
rc = len;
done:
mutex_unlock(&client->lock);
return rc;
}
static int occ_release(struct inode *inode, struct file *file)
{
struct occ_client *client = file->private_data;
put_device(client->occ->dev);
free_page((unsigned long)client->buffer);
kfree(client);
return 0;
}
static const struct file_operations occ_fops = {
.owner = THIS_MODULE,
.open = occ_open,
.read = occ_read,
.write = occ_write,
.release = occ_release,
};
static void occ_save_ffdc(struct occ *occ, __be32 *resp, size_t parsed_len,
size_t resp_len)
{
if (resp_len > parsed_len) {
size_t dh = resp_len - parsed_len;
size_t ffdc_len = (dh - 1) * 4; /* SBE words are four bytes */
__be32 *ffdc = &resp[parsed_len];
if (ffdc_len > occ->client_buffer_size)
ffdc_len = occ->client_buffer_size;
memcpy(occ->client_buffer, ffdc, ffdc_len);
occ->client_response_size = ffdc_len;
}
}
static int occ_verify_checksum(struct occ *occ, struct occ_response *resp,
u16 data_length)
{
/* Fetch the two bytes after the data for the checksum. */
u16 checksum_resp = get_unaligned_be16(&resp->data[data_length]);
u16 checksum;
u16 i;
checksum = resp->seq_no;
checksum += resp->cmd_type;
checksum += resp->return_status;
checksum += (data_length >> 8) + (data_length & 0xFF);
for (i = 0; i < data_length; ++i)
checksum += resp->data[i];
if (checksum != checksum_resp) {
dev_err(occ->dev, "Bad checksum: %04x!=%04x\n", checksum,
checksum_resp);
return -EBADE;
}
return 0;
}
static int occ_getsram(struct occ *occ, u32 offset, void *data, ssize_t len)
{
u32 data_len = ((len + 7) / 8) * 8; /* must be multiples of 8 B */
size_t cmd_len, parsed_len, resp_data_len;
size_t resp_len = OCC_MAX_RESP_WORDS;
__be32 *resp = occ->buffer;
__be32 cmd[6];
int idx = 0, rc;
/*
* Magic sequence to do SBE getsram command. SBE will fetch data from
* specified SRAM address.
*/
switch (occ->version) {
default:
case occ_p9:
cmd_len = 5;
cmd[2] = cpu_to_be32(1); /* Normal mode */
cmd[3] = cpu_to_be32(OCC_P9_SRAM_RSP_ADDR + offset);
break;
case occ_p10:
idx = 1;
cmd_len = 6;
cmd[2] = cpu_to_be32(OCC_P10_SRAM_MODE);
cmd[3] = 0;
cmd[4] = cpu_to_be32(OCC_P10_SRAM_RSP_ADDR + offset);
break;
}
cmd[0] = cpu_to_be32(cmd_len);
cmd[1] = cpu_to_be32(SBEFIFO_CMD_GET_OCC_SRAM);
cmd[4 + idx] = cpu_to_be32(data_len);
rc = sbefifo_submit(occ->sbefifo, cmd, cmd_len, resp, &resp_len);
if (rc)
return rc;
rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_GET_OCC_SRAM,
resp, resp_len, &parsed_len);
if (rc > 0) {
dev_err(occ->dev, "SRAM read returned failure status: %08x\n",
rc);
occ_save_ffdc(occ, resp, parsed_len, resp_len);
return -ECOMM;
} else if (rc) {
return rc;
}
resp_data_len = be32_to_cpu(resp[parsed_len - 1]);
if (resp_data_len != data_len) {
dev_err(occ->dev, "SRAM read expected %d bytes got %zd\n",
data_len, resp_data_len);
rc = -EBADMSG;
} else {
memcpy(data, resp, len);
}
return rc;
}
static int occ_putsram(struct occ *occ, const void *data, ssize_t len,
u8 seq_no, u16 checksum)
{
u32 data_len = ((len + 7) / 8) * 8; /* must be multiples of 8 B */
size_t cmd_len, parsed_len, resp_data_len;
size_t resp_len = OCC_MAX_RESP_WORDS;
__be32 *buf = occ->buffer;
u8 *byte_buf;
int idx = 0, rc;
cmd_len = (occ->version == occ_p10) ? 6 : 5;
cmd_len += data_len >> 2;
/*
* Magic sequence to do SBE putsram command. SBE will transfer
* data to specified SRAM address.
*/
buf[0] = cpu_to_be32(cmd_len);
buf[1] = cpu_to_be32(SBEFIFO_CMD_PUT_OCC_SRAM);
switch (occ->version) {
default:
case occ_p9:
buf[2] = cpu_to_be32(1); /* Normal mode */
buf[3] = cpu_to_be32(OCC_P9_SRAM_CMD_ADDR);
break;
case occ_p10:
idx = 1;
buf[2] = cpu_to_be32(OCC_P10_SRAM_MODE);
buf[3] = 0;
buf[4] = cpu_to_be32(OCC_P10_SRAM_CMD_ADDR);
break;
}
buf[4 + idx] = cpu_to_be32(data_len);
memcpy(&buf[5 + idx], data, len);
byte_buf = (u8 *)&buf[5 + idx];
/*
* Overwrite the first byte with our sequence number and the last two
* bytes with the checksum.
*/
byte_buf[0] = seq_no;
byte_buf[len - 2] = checksum >> 8;
byte_buf[len - 1] = checksum & 0xff;
rc = sbefifo_submit(occ->sbefifo, buf, cmd_len, buf, &resp_len);
if (rc)
return rc;
rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM,
buf, resp_len, &parsed_len);
if (rc > 0) {
dev_err(occ->dev, "SRAM write returned failure status: %08x\n",
rc);
occ_save_ffdc(occ, buf, parsed_len, resp_len);
return -ECOMM;
} else if (rc) {
return rc;
}
if (parsed_len != 1) {
dev_err(occ->dev, "SRAM write response length invalid: %zd\n",
parsed_len);
rc = -EBADMSG;
} else {
resp_data_len = be32_to_cpu(buf[0]);
if (resp_data_len != data_len) {
dev_err(occ->dev,
"SRAM write expected %d bytes got %zd\n",
data_len, resp_data_len);
rc = -EBADMSG;
}
}
return rc;
}
static int occ_trigger_attn(struct occ *occ)
{
__be32 *buf = occ->buffer;
size_t cmd_len, parsed_len, resp_data_len;
size_t resp_len = OCC_MAX_RESP_WORDS;
int idx = 0, rc;
switch (occ->version) {
default:
case occ_p9:
cmd_len = 7;
buf[2] = cpu_to_be32(3); /* Circular mode */
buf[3] = 0;
break;
case occ_p10:
idx = 1;
cmd_len = 8;
buf[2] = cpu_to_be32(0xd0); /* Circular mode, OCB Channel 1 */
buf[3] = 0;
buf[4] = 0;
break;
}
buf[0] = cpu_to_be32(cmd_len); /* Chip-op length in words */
buf[1] = cpu_to_be32(SBEFIFO_CMD_PUT_OCC_SRAM);
buf[4 + idx] = cpu_to_be32(8); /* Data length in bytes */
buf[5 + idx] = cpu_to_be32(0x20010000); /* Trigger OCC attention */
buf[6 + idx] = 0;
rc = sbefifo_submit(occ->sbefifo, buf, cmd_len, buf, &resp_len);
if (rc)
return rc;
rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM,
buf, resp_len, &parsed_len);
if (rc > 0) {
dev_err(occ->dev, "SRAM attn returned failure status: %08x\n",
rc);
occ_save_ffdc(occ, buf, parsed_len, resp_len);
return -ECOMM;
} else if (rc) {
return rc;
}
if (parsed_len != 1) {
dev_err(occ->dev, "SRAM attn response length invalid: %zd\n",
parsed_len);
rc = -EBADMSG;
} else {
resp_data_len = be32_to_cpu(buf[0]);
if (resp_data_len != 8) {
dev_err(occ->dev,
"SRAM attn expected 8 bytes got %zd\n",
resp_data_len);
rc = -EBADMSG;
}
}
return rc;
}
static bool fsi_occ_response_not_ready(struct occ_response *resp, u8 seq_no,
u8 cmd_type)
{
return resp->return_status == OCC_RESP_CMD_IN_PRG ||
resp->return_status == OCC_RESP_CRIT_INIT ||
resp->seq_no != seq_no || resp->cmd_type != cmd_type;
}
int fsi_occ_submit(struct device *dev, const void *request, size_t req_len,
void *response, size_t *resp_len)
{
const unsigned long timeout = msecs_to_jiffies(OCC_TIMEOUT_MS);
const unsigned long wait_time =
msecs_to_jiffies(OCC_CMD_IN_PRG_WAIT_MS);
struct occ *occ = dev_get_drvdata(dev);
struct occ_response *resp = response;
size_t user_resp_len = *resp_len;
u8 seq_no;
u8 cmd_type;
u16 checksum = 0;
u16 resp_data_length;
const u8 *byte_request = (const u8 *)request;
unsigned long end;
int rc;
size_t i;
*resp_len = 0;
if (!occ)
return -ENODEV;
if (user_resp_len < 7) {
dev_dbg(dev, "Bad resplen %zd\n", user_resp_len);
return -EINVAL;
}
cmd_type = byte_request[1];
/* Checksum the request, ignoring first byte (sequence number). */
for (i = 1; i < req_len - 2; ++i)
checksum += byte_request[i];
rc = mutex_lock_interruptible(&occ->occ_lock);
if (rc)
return rc;
occ->client_buffer = response;
occ->client_buffer_size = user_resp_len;
occ->client_response_size = 0;
if (!occ->buffer) {
rc = -ENOENT;
goto done;
}
/*
* Get a sequence number and update the counter. Avoid a sequence
* number of 0 which would pass the response check below even if the
* OCC response is uninitialized. Any sequence number the user is
* trying to send is overwritten since this function is the only common
* interface to the OCC and therefore the only place we can guarantee
* unique sequence numbers.
*/
seq_no = occ->sequence_number++;
if (!occ->sequence_number)
occ->sequence_number = 1;
checksum += seq_no;
rc = occ_putsram(occ, request, req_len, seq_no, checksum);
if (rc)
goto done;
rc = occ_trigger_attn(occ);
if (rc)
goto done;
end = jiffies + timeout;
while (true) {
/* Read occ response header */
rc = occ_getsram(occ, 0, resp, 8);
if (rc)
goto done;
if (fsi_occ_response_not_ready(resp, seq_no, cmd_type)) {
if (time_after(jiffies, end)) {
dev_err(occ->dev,
"resp timeout status=%02x seq=%d cmd=%d, our seq=%d cmd=%d\n",
resp->return_status, resp->seq_no,
resp->cmd_type, seq_no, cmd_type);
rc = -ETIMEDOUT;
goto done;
}
set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(wait_time);
} else {
/* Extract size of response data */
resp_data_length =
get_unaligned_be16(&resp->data_length);
/*
* Message size is data length + 5 bytes header + 2
* bytes checksum
*/
if ((resp_data_length + 7) > user_resp_len) {
rc = -EMSGSIZE;
goto done;
}
/*
* Get the entire response including the header again,
* in case it changed
*/
if (resp_data_length > 1) {
rc = occ_getsram(occ, 0, resp,
resp_data_length + 7);
if (rc)
goto done;
if (!fsi_occ_response_not_ready(resp, seq_no,
cmd_type))
break;
} else {
break;
}
}
}
dev_dbg(dev, "resp_status=%02x resp_data_len=%d\n",
resp->return_status, resp_data_length);
rc = occ_verify_checksum(occ, resp, resp_data_length);
if (rc)
goto done;
occ->client_response_size = resp_data_length + 7;
done:
*resp_len = occ->client_response_size;
mutex_unlock(&occ->occ_lock);
return rc;
}
EXPORT_SYMBOL_GPL(fsi_occ_submit);
static int occ_unregister_platform_child(struct device *dev, void *data)
{
struct platform_device *hwmon_dev = to_platform_device(dev);
platform_device_unregister(hwmon_dev);
return 0;
}
static int occ_unregister_of_child(struct device *dev, void *data)
{
struct platform_device *hwmon_dev = to_platform_device(dev);
of_device_unregister(hwmon_dev);
if (dev->of_node)
of_node_clear_flag(dev->of_node, OF_POPULATED);
return 0;
}
static int occ_probe(struct platform_device *pdev)
{
int rc;
u32 reg;
char child_name[32];
struct occ *occ;
struct platform_device *hwmon_dev = NULL;
struct device_node *hwmon_node;
struct device *dev = &pdev->dev;
struct platform_device_info hwmon_dev_info = {
.parent = dev,
.name = "occ-hwmon",
};
occ = devm_kzalloc(dev, sizeof(*occ), GFP_KERNEL);
if (!occ)
return -ENOMEM;
/* SBE words are always four bytes */
occ->buffer = kvmalloc(OCC_MAX_RESP_WORDS * 4, GFP_KERNEL);
if (!occ->buffer)
return -ENOMEM;
occ->version = (uintptr_t)of_device_get_match_data(dev);
occ->dev = dev;
occ->sbefifo = dev->parent;
/*
* Quickly derive a pseudo-random number from jiffies so that
* re-probing the driver doesn't accidentally overlap sequence numbers.
*/
occ->sequence_number = (u8)((jiffies % 0xff) + 1);
mutex_init(&occ->occ_lock);
if (dev->of_node) {
rc = of_property_read_u32(dev->of_node, "reg", ®);
if (!rc) {
/* make sure we don't have a duplicate from dts */
occ->idx = ida_alloc_range(&occ_ida, reg, reg,
GFP_KERNEL);
if (occ->idx < 0)
occ->idx = ida_alloc_min(&occ_ida, 1,
GFP_KERNEL);
} else {
occ->idx = ida_alloc_min(&occ_ida, 1, GFP_KERNEL);
}
} else {
occ->idx = ida_alloc_min(&occ_ida, 1, GFP_KERNEL);
}
platform_set_drvdata(pdev, occ);
snprintf(occ->name, sizeof(occ->name), "occ%d", occ->idx);
occ->mdev.fops = &occ_fops;
occ->mdev.minor = MISC_DYNAMIC_MINOR;
occ->mdev.name = occ->name;
occ->mdev.parent = dev;
rc = misc_register(&occ->mdev);
if (rc) {
dev_err(dev, "failed to register miscdevice: %d\n", rc);
ida_free(&occ_ida, occ->idx);
kvfree(occ->buffer);
return rc;
}
hwmon_node = of_get_child_by_name(dev->of_node, hwmon_dev_info.name);
if (hwmon_node) {
snprintf(child_name, sizeof(child_name), "%s.%d", hwmon_dev_info.name, occ->idx);
hwmon_dev = of_platform_device_create(hwmon_node, child_name, dev);
of_node_put(hwmon_node);
}
if (!hwmon_dev) {
occ->platform_hwmon = true;
hwmon_dev_info.id = occ->idx;
hwmon_dev = platform_device_register_full(&hwmon_dev_info);
if (IS_ERR(hwmon_dev))
dev_warn(dev, "failed to create hwmon device\n");
}
return 0;
}
static void occ_remove(struct platform_device *pdev)
{
struct occ *occ = platform_get_drvdata(pdev);
misc_deregister(&occ->mdev);
mutex_lock(&occ->occ_lock);
kvfree(occ->buffer);
occ->buffer = NULL;
mutex_unlock(&occ->occ_lock);
if (occ->platform_hwmon)
device_for_each_child(&pdev->dev, NULL, occ_unregister_platform_child);
else
device_for_each_child(&pdev->dev, NULL, occ_unregister_of_child);
ida_free(&occ_ida, occ->idx);
}
static const struct of_device_id occ_match[] = {
{
.compatible = "ibm,p9-occ",
.data = (void *)occ_p9
},
{
.compatible = "ibm,p10-occ",
.data = (void *)occ_p10
},
{ },
};
MODULE_DEVICE_TABLE(of, occ_match);
static struct platform_driver occ_driver = {
.driver = {
.name = "occ",
.of_match_table = occ_match,
},
.probe = occ_probe,
.remove_new = occ_remove,
};
static int occ_init(void)
{
return platform_driver_register(&occ_driver);
}
static void occ_exit(void)
{
platform_driver_unregister(&occ_driver);
ida_destroy(&occ_ida);
}
module_init(occ_init);
module_exit(occ_exit);
MODULE_AUTHOR("Eddie James <[email protected]>");
MODULE_DESCRIPTION("BMC P9 OCC driver");
MODULE_LICENSE("GPL");
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