// 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");