diff options
Diffstat (limited to 'drivers/fsi/fsi-scom.c')
| -rw-r--r-- | drivers/fsi/fsi-scom.c | 662 |
1 files changed, 662 insertions, 0 deletions
diff --git a/drivers/fsi/fsi-scom.c b/drivers/fsi/fsi-scom.c new file mode 100644 index 000000000..75d1389e2 --- /dev/null +++ b/drivers/fsi/fsi-scom.c @@ -0,0 +1,662 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * SCOM FSI Client device driver + * + * Copyright (C) IBM Corporation 2016 + */ + +#include <linux/fsi.h> +#include <linux/module.h> +#include <linux/cdev.h> +#include <linux/delay.h> +#include <linux/fs.h> +#include <linux/uaccess.h> +#include <linux/slab.h> +#include <linux/list.h> + +#include <uapi/linux/fsi.h> + +#define FSI_ENGID_SCOM 0x5 + +/* SCOM engine register set */ +#define SCOM_DATA0_REG 0x00 +#define SCOM_DATA1_REG 0x04 +#define SCOM_CMD_REG 0x08 +#define SCOM_FSI2PIB_RESET_REG 0x18 +#define SCOM_STATUS_REG 0x1C /* Read */ +#define SCOM_PIB_RESET_REG 0x1C /* Write */ + +/* Command register */ +#define SCOM_WRITE_CMD 0x80000000 +#define SCOM_READ_CMD 0x00000000 + +/* Status register bits */ +#define SCOM_STATUS_ERR_SUMMARY 0x80000000 +#define SCOM_STATUS_PROTECTION 0x01000000 +#define SCOM_STATUS_PARITY 0x04000000 +#define SCOM_STATUS_PIB_ABORT 0x00100000 +#define SCOM_STATUS_PIB_RESP_MASK 0x00007000 +#define SCOM_STATUS_PIB_RESP_SHIFT 12 + +#define SCOM_STATUS_FSI2PIB_ERROR (SCOM_STATUS_PROTECTION | \ + SCOM_STATUS_PARITY | \ + SCOM_STATUS_PIB_ABORT) +#define SCOM_STATUS_ANY_ERR (SCOM_STATUS_FSI2PIB_ERROR | \ + SCOM_STATUS_PIB_RESP_MASK) +/* SCOM address encodings */ +#define XSCOM_ADDR_IND_FLAG BIT_ULL(63) +#define XSCOM_ADDR_INF_FORM1 BIT_ULL(60) + +/* SCOM indirect stuff */ +#define XSCOM_ADDR_DIRECT_PART 0x7fffffffull +#define XSCOM_ADDR_INDIRECT_PART 0x000fffff00000000ull +#define XSCOM_DATA_IND_READ BIT_ULL(63) +#define XSCOM_DATA_IND_COMPLETE BIT_ULL(31) +#define XSCOM_DATA_IND_ERR_MASK 0x70000000ull +#define XSCOM_DATA_IND_ERR_SHIFT 28 +#define XSCOM_DATA_IND_DATA 0x0000ffffull +#define XSCOM_DATA_IND_FORM1_DATA 0x000fffffffffffffull +#define XSCOM_ADDR_FORM1_LOW 0x000ffffffffull +#define XSCOM_ADDR_FORM1_HI 0xfff00000000ull +#define XSCOM_ADDR_FORM1_HI_SHIFT 20 + +/* Retries */ +#define SCOM_MAX_RETRIES 100 /* Retries on busy */ +#define SCOM_MAX_IND_RETRIES 10 /* Retries indirect not ready */ + +struct scom_device { + struct list_head link; + struct fsi_device *fsi_dev; + struct device dev; + struct cdev cdev; + struct mutex lock; + bool dead; +}; + +static int __put_scom(struct scom_device *scom_dev, uint64_t value, + uint32_t addr, uint32_t *status) +{ + __be32 data, raw_status; + int rc; + + data = cpu_to_be32((value >> 32) & 0xffffffff); + rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA0_REG, &data, + sizeof(uint32_t)); + if (rc) + return rc; + + data = cpu_to_be32(value & 0xffffffff); + rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA1_REG, &data, + sizeof(uint32_t)); + if (rc) + return rc; + + data = cpu_to_be32(SCOM_WRITE_CMD | addr); + rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data, + sizeof(uint32_t)); + if (rc) + return rc; + rc = fsi_device_read(scom_dev->fsi_dev, SCOM_STATUS_REG, &raw_status, + sizeof(uint32_t)); + if (rc) + return rc; + *status = be32_to_cpu(raw_status); + + return 0; +} + +static int __get_scom(struct scom_device *scom_dev, uint64_t *value, + uint32_t addr, uint32_t *status) +{ + __be32 data, raw_status; + int rc; + + + *value = 0ULL; + data = cpu_to_be32(SCOM_READ_CMD | addr); + rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data, + sizeof(uint32_t)); + if (rc) + return rc; + rc = fsi_device_read(scom_dev->fsi_dev, SCOM_STATUS_REG, &raw_status, + sizeof(uint32_t)); + if (rc) + return rc; + + /* + * Read the data registers even on error, so we don't have + * to interpret the status register here. + */ + rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA0_REG, &data, + sizeof(uint32_t)); + if (rc) + return rc; + *value |= (uint64_t)be32_to_cpu(data) << 32; + rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA1_REG, &data, + sizeof(uint32_t)); + if (rc) + return rc; + *value |= be32_to_cpu(data); + *status = be32_to_cpu(raw_status); + + return rc; +} + +static int put_indirect_scom_form0(struct scom_device *scom, uint64_t value, + uint64_t addr, uint32_t *status) +{ + uint64_t ind_data, ind_addr; + int rc, retries, err = 0; + + if (value & ~XSCOM_DATA_IND_DATA) + return -EINVAL; + + ind_addr = addr & XSCOM_ADDR_DIRECT_PART; + ind_data = (addr & XSCOM_ADDR_INDIRECT_PART) | value; + rc = __put_scom(scom, ind_data, ind_addr, status); + if (rc || (*status & SCOM_STATUS_ANY_ERR)) + return rc; + + for (retries = 0; retries < SCOM_MAX_IND_RETRIES; retries++) { + rc = __get_scom(scom, &ind_data, addr, status); + if (rc || (*status & SCOM_STATUS_ANY_ERR)) + return rc; + + err = (ind_data & XSCOM_DATA_IND_ERR_MASK) >> XSCOM_DATA_IND_ERR_SHIFT; + *status = err << SCOM_STATUS_PIB_RESP_SHIFT; + if ((ind_data & XSCOM_DATA_IND_COMPLETE) || (err != SCOM_PIB_BLOCKED)) + return 0; + + msleep(1); + } + return rc; +} + +static int put_indirect_scom_form1(struct scom_device *scom, uint64_t value, + uint64_t addr, uint32_t *status) +{ + uint64_t ind_data, ind_addr; + + if (value & ~XSCOM_DATA_IND_FORM1_DATA) + return -EINVAL; + + ind_addr = addr & XSCOM_ADDR_FORM1_LOW; + ind_data = value | (addr & XSCOM_ADDR_FORM1_HI) << XSCOM_ADDR_FORM1_HI_SHIFT; + return __put_scom(scom, ind_data, ind_addr, status); +} + +static int get_indirect_scom_form0(struct scom_device *scom, uint64_t *value, + uint64_t addr, uint32_t *status) +{ + uint64_t ind_data, ind_addr; + int rc, retries, err = 0; + + ind_addr = addr & XSCOM_ADDR_DIRECT_PART; + ind_data = (addr & XSCOM_ADDR_INDIRECT_PART) | XSCOM_DATA_IND_READ; + rc = __put_scom(scom, ind_data, ind_addr, status); + if (rc || (*status & SCOM_STATUS_ANY_ERR)) + return rc; + + for (retries = 0; retries < SCOM_MAX_IND_RETRIES; retries++) { + rc = __get_scom(scom, &ind_data, addr, status); + if (rc || (*status & SCOM_STATUS_ANY_ERR)) + return rc; + + err = (ind_data & XSCOM_DATA_IND_ERR_MASK) >> XSCOM_DATA_IND_ERR_SHIFT; + *status = err << SCOM_STATUS_PIB_RESP_SHIFT; + *value = ind_data & XSCOM_DATA_IND_DATA; + + if ((ind_data & XSCOM_DATA_IND_COMPLETE) || (err != SCOM_PIB_BLOCKED)) + return 0; + + msleep(1); + } + return rc; +} + +static int raw_put_scom(struct scom_device *scom, uint64_t value, + uint64_t addr, uint32_t *status) +{ + if (addr & XSCOM_ADDR_IND_FLAG) { + if (addr & XSCOM_ADDR_INF_FORM1) + return put_indirect_scom_form1(scom, value, addr, status); + else + return put_indirect_scom_form0(scom, value, addr, status); + } else + return __put_scom(scom, value, addr, status); +} + +static int raw_get_scom(struct scom_device *scom, uint64_t *value, + uint64_t addr, uint32_t *status) +{ + if (addr & XSCOM_ADDR_IND_FLAG) { + if (addr & XSCOM_ADDR_INF_FORM1) + return -ENXIO; + return get_indirect_scom_form0(scom, value, addr, status); + } else + return __get_scom(scom, value, addr, status); +} + +static int handle_fsi2pib_status(struct scom_device *scom, uint32_t status) +{ + uint32_t dummy = -1; + + if (status & SCOM_STATUS_FSI2PIB_ERROR) + fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy, + sizeof(uint32_t)); + + if (status & SCOM_STATUS_PROTECTION) + return -EPERM; + if (status & SCOM_STATUS_PARITY) + return -EIO; + /* Return -EBUSY on PIB abort to force a retry */ + if (status & SCOM_STATUS_PIB_ABORT) + return -EBUSY; + return 0; +} + +static int handle_pib_status(struct scom_device *scom, uint8_t status) +{ + uint32_t dummy = -1; + + if (status == SCOM_PIB_SUCCESS) + return 0; + if (status == SCOM_PIB_BLOCKED) + return -EBUSY; + + /* Reset the bridge */ + fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy, + sizeof(uint32_t)); + + switch(status) { + case SCOM_PIB_OFFLINE: + return -ENODEV; + case SCOM_PIB_BAD_ADDR: + return -ENXIO; + case SCOM_PIB_TIMEOUT: + return -ETIMEDOUT; + case SCOM_PIB_PARTIAL: + case SCOM_PIB_CLK_ERR: + case SCOM_PIB_PARITY_ERR: + default: + return -EIO; + } +} + +static int put_scom(struct scom_device *scom, uint64_t value, + uint64_t addr) +{ + uint32_t status, dummy = -1; + int rc, retries; + + for (retries = 0; retries < SCOM_MAX_RETRIES; retries++) { + rc = raw_put_scom(scom, value, addr, &status); + if (rc) { + /* Try resetting the bridge if FSI fails */ + if (rc != -ENODEV && retries == 0) { + fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, + &dummy, sizeof(uint32_t)); + rc = -EBUSY; + } else + return rc; + } else + rc = handle_fsi2pib_status(scom, status); + if (rc && rc != -EBUSY) + break; + if (rc == 0) { + rc = handle_pib_status(scom, + (status & SCOM_STATUS_PIB_RESP_MASK) + >> SCOM_STATUS_PIB_RESP_SHIFT); + if (rc && rc != -EBUSY) + break; + } + if (rc == 0) + break; + msleep(1); + } + return rc; +} + +static int get_scom(struct scom_device *scom, uint64_t *value, + uint64_t addr) +{ + uint32_t status, dummy = -1; + int rc, retries; + + for (retries = 0; retries < SCOM_MAX_RETRIES; retries++) { + rc = raw_get_scom(scom, value, addr, &status); + if (rc) { + /* Try resetting the bridge if FSI fails */ + if (rc != -ENODEV && retries == 0) { + fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, + &dummy, sizeof(uint32_t)); + rc = -EBUSY; + } else + return rc; + } else + rc = handle_fsi2pib_status(scom, status); + if (rc && rc != -EBUSY) + break; + if (rc == 0) { + rc = handle_pib_status(scom, + (status & SCOM_STATUS_PIB_RESP_MASK) + >> SCOM_STATUS_PIB_RESP_SHIFT); + if (rc && rc != -EBUSY) + break; + } + if (rc == 0) + break; + msleep(1); + } + return rc; +} + +static ssize_t scom_read(struct file *filep, char __user *buf, size_t len, + loff_t *offset) +{ + struct scom_device *scom = filep->private_data; + struct device *dev = &scom->fsi_dev->dev; + uint64_t val; + int rc; + + if (len != sizeof(uint64_t)) + return -EINVAL; + + mutex_lock(&scom->lock); + if (scom->dead) + rc = -ENODEV; + else + rc = get_scom(scom, &val, *offset); + mutex_unlock(&scom->lock); + if (rc) { + dev_dbg(dev, "get_scom fail:%d\n", rc); + return rc; + } + + rc = copy_to_user(buf, &val, len); + if (rc) + dev_dbg(dev, "copy to user failed:%d\n", rc); + + return rc ? rc : len; +} + +static ssize_t scom_write(struct file *filep, const char __user *buf, + size_t len, loff_t *offset) +{ + int rc; + struct scom_device *scom = filep->private_data; + struct device *dev = &scom->fsi_dev->dev; + uint64_t val; + + if (len != sizeof(uint64_t)) + return -EINVAL; + + rc = copy_from_user(&val, buf, len); + if (rc) { + dev_dbg(dev, "copy from user failed:%d\n", rc); + return -EINVAL; + } + + mutex_lock(&scom->lock); + if (scom->dead) + rc = -ENODEV; + else + rc = put_scom(scom, val, *offset); + mutex_unlock(&scom->lock); + if (rc) { + dev_dbg(dev, "put_scom failed with:%d\n", rc); + return rc; + } + + return len; +} + +static loff_t scom_llseek(struct file *file, loff_t offset, int whence) +{ + switch (whence) { + case SEEK_CUR: + break; + case SEEK_SET: + file->f_pos = offset; + break; + default: + return -EINVAL; + } + + return offset; +} + +static void raw_convert_status(struct scom_access *acc, uint32_t status) +{ + acc->pib_status = (status & SCOM_STATUS_PIB_RESP_MASK) >> + SCOM_STATUS_PIB_RESP_SHIFT; + acc->intf_errors = 0; + + if (status & SCOM_STATUS_PROTECTION) + acc->intf_errors |= SCOM_INTF_ERR_PROTECTION; + else if (status & SCOM_STATUS_PARITY) + acc->intf_errors |= SCOM_INTF_ERR_PARITY; + else if (status & SCOM_STATUS_PIB_ABORT) + acc->intf_errors |= SCOM_INTF_ERR_ABORT; + else if (status & SCOM_STATUS_ERR_SUMMARY) + acc->intf_errors |= SCOM_INTF_ERR_UNKNOWN; +} + +static int scom_raw_read(struct scom_device *scom, void __user *argp) +{ + struct scom_access acc; + uint32_t status; + int rc; + + if (copy_from_user(&acc, argp, sizeof(struct scom_access))) + return -EFAULT; + + rc = raw_get_scom(scom, &acc.data, acc.addr, &status); + if (rc) + return rc; + raw_convert_status(&acc, status); + if (copy_to_user(argp, &acc, sizeof(struct scom_access))) + return -EFAULT; + return 0; +} + +static int scom_raw_write(struct scom_device *scom, void __user *argp) +{ + u64 prev_data, mask, data; + struct scom_access acc; + uint32_t status; + int rc; + + if (copy_from_user(&acc, argp, sizeof(struct scom_access))) + return -EFAULT; + + if (acc.mask) { + rc = raw_get_scom(scom, &prev_data, acc.addr, &status); + if (rc) + return rc; + if (status & SCOM_STATUS_ANY_ERR) + goto fail; + mask = acc.mask; + } else { + prev_data = mask = -1ull; + } + data = (prev_data & ~mask) | (acc.data & mask); + rc = raw_put_scom(scom, data, acc.addr, &status); + if (rc) + return rc; + fail: + raw_convert_status(&acc, status); + if (copy_to_user(argp, &acc, sizeof(struct scom_access))) + return -EFAULT; + return 0; +} + +static int scom_reset(struct scom_device *scom, void __user *argp) +{ + uint32_t flags, dummy = -1; + int rc = 0; + + if (get_user(flags, (__u32 __user *)argp)) + return -EFAULT; + if (flags & SCOM_RESET_PIB) + rc = fsi_device_write(scom->fsi_dev, SCOM_PIB_RESET_REG, &dummy, + sizeof(uint32_t)); + if (!rc && (flags & (SCOM_RESET_PIB | SCOM_RESET_INTF))) + rc = fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy, + sizeof(uint32_t)); + return rc; +} + +static int scom_check(struct scom_device *scom, void __user *argp) +{ + /* Still need to find out how to get "protected" */ + return put_user(SCOM_CHECK_SUPPORTED, (__u32 __user *)argp); +} + +static long scom_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct scom_device *scom = file->private_data; + void __user *argp = (void __user *)arg; + int rc = -ENOTTY; + + mutex_lock(&scom->lock); + if (scom->dead) { + mutex_unlock(&scom->lock); + return -ENODEV; + } + switch(cmd) { + case FSI_SCOM_CHECK: + rc = scom_check(scom, argp); + break; + case FSI_SCOM_READ: + rc = scom_raw_read(scom, argp); + break; + case FSI_SCOM_WRITE: + rc = scom_raw_write(scom, argp); + break; + case FSI_SCOM_RESET: + rc = scom_reset(scom, argp); + break; + } + mutex_unlock(&scom->lock); + return rc; +} + +static int scom_open(struct inode *inode, struct file *file) +{ + struct scom_device *scom = container_of(inode->i_cdev, struct scom_device, cdev); + + file->private_data = scom; + + return 0; +} + +static const struct file_operations scom_fops = { + .owner = THIS_MODULE, + .open = scom_open, + .llseek = scom_llseek, + .read = scom_read, + .write = scom_write, + .unlocked_ioctl = scom_ioctl, +}; + +static void scom_free(struct device *dev) +{ + struct scom_device *scom = container_of(dev, struct scom_device, dev); + + put_device(&scom->fsi_dev->dev); + kfree(scom); +} + +static int scom_probe(struct device *dev) +{ + struct fsi_device *fsi_dev = to_fsi_dev(dev); + struct scom_device *scom; + int rc, didx; + + scom = kzalloc(sizeof(*scom), GFP_KERNEL); + if (!scom) + return -ENOMEM; + dev_set_drvdata(dev, scom); + mutex_init(&scom->lock); + + /* Grab a reference to the device (parent of our cdev), we'll drop it later */ + if (!get_device(dev)) { + kfree(scom); + return -ENODEV; + } + scom->fsi_dev = fsi_dev; + + /* Create chardev for userspace access */ + scom->dev.type = &fsi_cdev_type; + scom->dev.parent = dev; + scom->dev.release = scom_free; + device_initialize(&scom->dev); + + /* Allocate a minor in the FSI space */ + rc = fsi_get_new_minor(fsi_dev, fsi_dev_scom, &scom->dev.devt, &didx); + if (rc) + goto err; + + dev_set_name(&scom->dev, "scom%d", didx); + cdev_init(&scom->cdev, &scom_fops); + rc = cdev_device_add(&scom->cdev, &scom->dev); + if (rc) { + dev_err(dev, "Error %d creating char device %s\n", + rc, dev_name(&scom->dev)); + goto err_free_minor; + } + + return 0; + err_free_minor: + fsi_free_minor(scom->dev.devt); + err: + put_device(&scom->dev); + return rc; +} + +static int scom_remove(struct device *dev) +{ + struct scom_device *scom = dev_get_drvdata(dev); + + mutex_lock(&scom->lock); + scom->dead = true; + mutex_unlock(&scom->lock); + cdev_device_del(&scom->cdev, &scom->dev); + fsi_free_minor(scom->dev.devt); + put_device(&scom->dev); + + return 0; +} + +static const struct fsi_device_id scom_ids[] = { + { + .engine_type = FSI_ENGID_SCOM, + .version = FSI_VERSION_ANY, + }, + { 0 } +}; + +static struct fsi_driver scom_drv = { + .id_table = scom_ids, + .drv = { + .name = "scom", + .bus = &fsi_bus_type, + .probe = scom_probe, + .remove = scom_remove, + } +}; + +static int scom_init(void) +{ + return fsi_driver_register(&scom_drv); +} + +static void scom_exit(void) +{ + fsi_driver_unregister(&scom_drv); +} + +module_init(scom_init); +module_exit(scom_exit); +MODULE_LICENSE("GPL"); |