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- // 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/module.h>
- #include <linux/mutex.h>
- #include <linux/fsi-occ.h>
- #include <linux/of.h>
- #include <linux/platform_device.h>
- #include <linux/sched.h>
- #include <linux/slab.h>
- #include <linux/uaccess.h>
- #include <asm/unaligned.h>
- #define OCC_SRAM_BYTES 4096
- #define OCC_CMD_DATA_BYTES 4090
- #define OCC_RESP_DATA_BYTES 4089
- #define OCC_SRAM_CMD_ADDR 0xFFFBE000
- #define OCC_SRAM_RSP_ADDR 0xFFFBF000
- /*
- * Assume we don't have much FFDC, if we do we'll overflow and
- * fail the command. This needs to be big enough for simple
- * commands as well.
- */
- #define OCC_SBE_STATUS_WORDS 32
- #define OCC_TIMEOUT_MS 1000
- #define OCC_CMD_IN_PRG_WAIT_MS 50
- struct occ {
- struct device *dev;
- struct device *sbefifo;
- char name[32];
- int idx;
- 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;
- /* 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;
- u16 checksum = 0;
- ssize_t rc, i;
- 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;
- /* Sequence number (we could increment and compare with response) */
- cmd[0] = 1;
- /*
- * 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;
- }
- /* Calculate checksum */
- for (i = 0; i < data_length + 4; ++i)
- checksum += cmd[i];
- cmd[data_length + 4] = checksum >> 8;
- cmd[data_length + 5] = checksum & 0xFF;
- /* Submit command */
- 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;
- 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 int occ_verify_checksum(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)
- return -EBADMSG;
- return 0;
- }
- static int occ_getsram(struct occ *occ, u32 address, void *data, ssize_t len)
- {
- u32 data_len = ((len + 7) / 8) * 8; /* must be multiples of 8 B */
- size_t resp_len, resp_data_len;
- __be32 *resp, cmd[5];
- int rc;
- /*
- * Magic sequence to do SBE getsram command. SBE will fetch data from
- * specified SRAM address.
- */
- cmd[0] = cpu_to_be32(0x5);
- cmd[1] = cpu_to_be32(SBEFIFO_CMD_GET_OCC_SRAM);
- cmd[2] = cpu_to_be32(1);
- cmd[3] = cpu_to_be32(address);
- cmd[4] = cpu_to_be32(data_len);
- resp_len = (data_len >> 2) + OCC_SBE_STATUS_WORDS;
- resp = kzalloc(resp_len << 2, GFP_KERNEL);
- if (!resp)
- return -ENOMEM;
- rc = sbefifo_submit(occ->sbefifo, cmd, 5, resp, &resp_len);
- if (rc)
- goto free;
- rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_GET_OCC_SRAM,
- resp, resp_len, &resp_len);
- if (rc)
- goto free;
- resp_data_len = be32_to_cpu(resp[resp_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);
- }
- free:
- /* Convert positive SBEI status */
- if (rc > 0) {
- dev_err(occ->dev, "SRAM read returned failure status: %08x\n",
- rc);
- rc = -EBADMSG;
- }
- kfree(resp);
- return rc;
- }
- static int occ_putsram(struct occ *occ, u32 address, const void *data,
- ssize_t len)
- {
- size_t cmd_len, buf_len, resp_len, resp_data_len;
- u32 data_len = ((len + 7) / 8) * 8; /* must be multiples of 8 B */
- __be32 *buf;
- int rc;
- /*
- * We use the same buffer for command and response, make
- * sure it's big enough
- */
- resp_len = OCC_SBE_STATUS_WORDS;
- cmd_len = (data_len >> 2) + 5;
- buf_len = max(cmd_len, resp_len);
- buf = kzalloc(buf_len << 2, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
- /*
- * 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);
- buf[2] = cpu_to_be32(1);
- buf[3] = cpu_to_be32(address);
- buf[4] = cpu_to_be32(data_len);
- memcpy(&buf[5], data, len);
- rc = sbefifo_submit(occ->sbefifo, buf, cmd_len, buf, &resp_len);
- if (rc)
- goto free;
- rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM,
- buf, resp_len, &resp_len);
- if (rc)
- goto free;
- if (resp_len != 1) {
- dev_err(occ->dev, "SRAM write response length invalid: %zd\n",
- resp_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;
- }
- }
- free:
- /* Convert positive SBEI status */
- if (rc > 0) {
- dev_err(occ->dev, "SRAM write returned failure status: %08x\n",
- rc);
- rc = -EBADMSG;
- }
- kfree(buf);
- return rc;
- }
- static int occ_trigger_attn(struct occ *occ)
- {
- __be32 buf[OCC_SBE_STATUS_WORDS];
- size_t resp_len, resp_data_len;
- int rc;
- BUILD_BUG_ON(OCC_SBE_STATUS_WORDS < 7);
- resp_len = OCC_SBE_STATUS_WORDS;
- buf[0] = cpu_to_be32(0x5 + 0x2); /* Chip-op length in words */
- buf[1] = cpu_to_be32(SBEFIFO_CMD_PUT_OCC_SRAM);
- buf[2] = cpu_to_be32(0x3); /* Mode: Circular */
- buf[3] = cpu_to_be32(0x0); /* Address: ignore in mode 3 */
- buf[4] = cpu_to_be32(0x8); /* Data length in bytes */
- buf[5] = cpu_to_be32(0x20010000); /* Trigger OCC attention */
- buf[6] = 0;
- rc = sbefifo_submit(occ->sbefifo, buf, 7, buf, &resp_len);
- if (rc)
- goto error;
- rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM,
- buf, resp_len, &resp_len);
- if (rc)
- goto error;
- if (resp_len != 1) {
- dev_err(occ->dev, "SRAM attn response length invalid: %zd\n",
- resp_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;
- }
- }
- error:
- /* Convert positive SBEI status */
- if (rc > 0) {
- dev_err(occ->dev, "SRAM attn returned failure status: %08x\n",
- rc);
- rc = -EBADMSG;
- }
- return rc;
- }
- 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;
- u8 seq_no;
- u16 resp_data_length;
- unsigned long start;
- int rc;
- if (!occ)
- return -ENODEV;
- if (*resp_len < 7) {
- dev_dbg(dev, "Bad resplen %zd\n", *resp_len);
- return -EINVAL;
- }
- mutex_lock(&occ->occ_lock);
- /* Extract the seq_no from the command (first byte) */
- seq_no = *(const u8 *)request;
- rc = occ_putsram(occ, OCC_SRAM_CMD_ADDR, request, req_len);
- if (rc)
- goto done;
- rc = occ_trigger_attn(occ);
- if (rc)
- goto done;
- /* Read occ response header */
- start = jiffies;
- do {
- rc = occ_getsram(occ, OCC_SRAM_RSP_ADDR, resp, 8);
- if (rc)
- goto done;
- if (resp->return_status == OCC_RESP_CMD_IN_PRG ||
- resp->return_status == OCC_RESP_CRIT_INIT ||
- resp->seq_no != seq_no) {
- rc = -ETIMEDOUT;
- if (time_after(jiffies, start + timeout)) {
- dev_err(occ->dev, "resp timeout status=%02x "
- "resp seq_no=%d our seq_no=%d\n",
- resp->return_status, resp->seq_no,
- seq_no);
- goto done;
- }
- set_current_state(TASK_UNINTERRUPTIBLE);
- schedule_timeout(wait_time);
- }
- } while (rc);
- /* 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) > *resp_len) {
- rc = -EMSGSIZE;
- goto done;
- }
- dev_dbg(dev, "resp_status=%02x resp_data_len=%d\n",
- resp->return_status, resp_data_length);
- /* Grab the rest */
- if (resp_data_length > 1) {
- /* already got 3 bytes resp, also need 2 bytes checksum */
- rc = occ_getsram(occ, OCC_SRAM_RSP_ADDR + 8,
- &resp->data[3], resp_data_length - 1);
- if (rc)
- goto done;
- }
- *resp_len = resp_data_length + 7;
- rc = occ_verify_checksum(resp, resp_data_length);
- done:
- mutex_unlock(&occ->occ_lock);
- return rc;
- }
- EXPORT_SYMBOL_GPL(fsi_occ_submit);
- static int occ_unregister_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_probe(struct platform_device *pdev)
- {
- int rc;
- u32 reg;
- struct occ *occ;
- struct platform_device *hwmon_dev;
- 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;
- occ->dev = dev;
- occ->sbefifo = dev->parent;
- 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_simple_get(&occ_ida, reg, reg + 1,
- GFP_KERNEL);
- if (occ->idx < 0)
- occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
- GFP_KERNEL);
- } else {
- occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
- GFP_KERNEL);
- }
- } else {
- occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX, 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_simple_remove(&occ_ida, occ->idx);
- return rc;
- }
- 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 int occ_remove(struct platform_device *pdev)
- {
- struct occ *occ = platform_get_drvdata(pdev);
- misc_deregister(&occ->mdev);
- device_for_each_child(&pdev->dev, NULL, occ_unregister_child);
- ida_simple_remove(&occ_ida, occ->idx);
- return 0;
- }
- static const struct of_device_id occ_match[] = {
- { .compatible = "ibm,p9-occ" },
- { },
- };
- MODULE_DEVICE_TABLE(of, occ_match);
- static struct platform_driver occ_driver = {
- .driver = {
- .name = "occ",
- .of_match_table = occ_match,
- },
- .probe = occ_probe,
- .remove = 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 <eajames@linux.ibm.com>");
- MODULE_DESCRIPTION("BMC P9 OCC driver");
- MODULE_LICENSE("GPL");
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