diff options
Diffstat (limited to 'drivers/char/ipmi/kcs_bmc.c')
| -rw-r--r-- | drivers/char/ipmi/kcs_bmc.c | 458 |
1 files changed, 458 insertions, 0 deletions
diff --git a/drivers/char/ipmi/kcs_bmc.c b/drivers/char/ipmi/kcs_bmc.c new file mode 100644 index 000000000..f292e74bd --- /dev/null +++ b/drivers/char/ipmi/kcs_bmc.c @@ -0,0 +1,458 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2015-2018, Intel Corporation. + */ + +#define pr_fmt(fmt) "kcs-bmc: " fmt + +#include <linux/errno.h> +#include <linux/io.h> +#include <linux/ipmi_bmc.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/poll.h> +#include <linux/sched.h> +#include <linux/slab.h> + +#include "kcs_bmc.h" + +#define DEVICE_NAME "ipmi-kcs" + +#define KCS_MSG_BUFSIZ 1000 + +#define KCS_ZERO_DATA 0 + + +/* IPMI 2.0 - Table 9-1, KCS Interface Status Register Bits */ +#define KCS_STATUS_STATE(state) (state << 6) +#define KCS_STATUS_STATE_MASK GENMASK(7, 6) +#define KCS_STATUS_CMD_DAT BIT(3) +#define KCS_STATUS_SMS_ATN BIT(2) +#define KCS_STATUS_IBF BIT(1) +#define KCS_STATUS_OBF BIT(0) + +/* IPMI 2.0 - Table 9-2, KCS Interface State Bits */ +enum kcs_states { + IDLE_STATE = 0, + READ_STATE = 1, + WRITE_STATE = 2, + ERROR_STATE = 3, +}; + +/* IPMI 2.0 - Table 9-3, KCS Interface Control Codes */ +#define KCS_CMD_GET_STATUS_ABORT 0x60 +#define KCS_CMD_WRITE_START 0x61 +#define KCS_CMD_WRITE_END 0x62 +#define KCS_CMD_READ_BYTE 0x68 + +static inline u8 read_data(struct kcs_bmc *kcs_bmc) +{ + return kcs_bmc->io_inputb(kcs_bmc, kcs_bmc->ioreg.idr); +} + +static inline void write_data(struct kcs_bmc *kcs_bmc, u8 data) +{ + kcs_bmc->io_outputb(kcs_bmc, kcs_bmc->ioreg.odr, data); +} + +static inline u8 read_status(struct kcs_bmc *kcs_bmc) +{ + return kcs_bmc->io_inputb(kcs_bmc, kcs_bmc->ioreg.str); +} + +static inline void write_status(struct kcs_bmc *kcs_bmc, u8 data) +{ + kcs_bmc->io_outputb(kcs_bmc, kcs_bmc->ioreg.str, data); +} + +static void update_status_bits(struct kcs_bmc *kcs_bmc, u8 mask, u8 val) +{ + u8 tmp = read_status(kcs_bmc); + + tmp &= ~mask; + tmp |= val & mask; + + write_status(kcs_bmc, tmp); +} + +static inline void set_state(struct kcs_bmc *kcs_bmc, u8 state) +{ + update_status_bits(kcs_bmc, KCS_STATUS_STATE_MASK, + KCS_STATUS_STATE(state)); +} + +static void kcs_force_abort(struct kcs_bmc *kcs_bmc) +{ + set_state(kcs_bmc, ERROR_STATE); + read_data(kcs_bmc); + write_data(kcs_bmc, KCS_ZERO_DATA); + + kcs_bmc->phase = KCS_PHASE_ERROR; + kcs_bmc->data_in_avail = false; + kcs_bmc->data_in_idx = 0; +} + +static void kcs_bmc_handle_data(struct kcs_bmc *kcs_bmc) +{ + u8 data; + + switch (kcs_bmc->phase) { + case KCS_PHASE_WRITE_START: + kcs_bmc->phase = KCS_PHASE_WRITE_DATA; + fallthrough; + + case KCS_PHASE_WRITE_DATA: + if (kcs_bmc->data_in_idx < KCS_MSG_BUFSIZ) { + set_state(kcs_bmc, WRITE_STATE); + write_data(kcs_bmc, KCS_ZERO_DATA); + kcs_bmc->data_in[kcs_bmc->data_in_idx++] = + read_data(kcs_bmc); + } else { + kcs_force_abort(kcs_bmc); + kcs_bmc->error = KCS_LENGTH_ERROR; + } + break; + + case KCS_PHASE_WRITE_END_CMD: + if (kcs_bmc->data_in_idx < KCS_MSG_BUFSIZ) { + set_state(kcs_bmc, READ_STATE); + kcs_bmc->data_in[kcs_bmc->data_in_idx++] = + read_data(kcs_bmc); + kcs_bmc->phase = KCS_PHASE_WRITE_DONE; + kcs_bmc->data_in_avail = true; + wake_up_interruptible(&kcs_bmc->queue); + } else { + kcs_force_abort(kcs_bmc); + kcs_bmc->error = KCS_LENGTH_ERROR; + } + break; + + case KCS_PHASE_READ: + if (kcs_bmc->data_out_idx == kcs_bmc->data_out_len) + set_state(kcs_bmc, IDLE_STATE); + + data = read_data(kcs_bmc); + if (data != KCS_CMD_READ_BYTE) { + set_state(kcs_bmc, ERROR_STATE); + write_data(kcs_bmc, KCS_ZERO_DATA); + break; + } + + if (kcs_bmc->data_out_idx == kcs_bmc->data_out_len) { + write_data(kcs_bmc, KCS_ZERO_DATA); + kcs_bmc->phase = KCS_PHASE_IDLE; + break; + } + + write_data(kcs_bmc, + kcs_bmc->data_out[kcs_bmc->data_out_idx++]); + break; + + case KCS_PHASE_ABORT_ERROR1: + set_state(kcs_bmc, READ_STATE); + read_data(kcs_bmc); + write_data(kcs_bmc, kcs_bmc->error); + kcs_bmc->phase = KCS_PHASE_ABORT_ERROR2; + break; + + case KCS_PHASE_ABORT_ERROR2: + set_state(kcs_bmc, IDLE_STATE); + read_data(kcs_bmc); + write_data(kcs_bmc, KCS_ZERO_DATA); + kcs_bmc->phase = KCS_PHASE_IDLE; + break; + + default: + kcs_force_abort(kcs_bmc); + break; + } +} + +static void kcs_bmc_handle_cmd(struct kcs_bmc *kcs_bmc) +{ + u8 cmd; + + set_state(kcs_bmc, WRITE_STATE); + write_data(kcs_bmc, KCS_ZERO_DATA); + + cmd = read_data(kcs_bmc); + switch (cmd) { + case KCS_CMD_WRITE_START: + kcs_bmc->phase = KCS_PHASE_WRITE_START; + kcs_bmc->error = KCS_NO_ERROR; + kcs_bmc->data_in_avail = false; + kcs_bmc->data_in_idx = 0; + break; + + case KCS_CMD_WRITE_END: + if (kcs_bmc->phase != KCS_PHASE_WRITE_DATA) { + kcs_force_abort(kcs_bmc); + break; + } + + kcs_bmc->phase = KCS_PHASE_WRITE_END_CMD; + break; + + case KCS_CMD_GET_STATUS_ABORT: + if (kcs_bmc->error == KCS_NO_ERROR) + kcs_bmc->error = KCS_ABORTED_BY_COMMAND; + + kcs_bmc->phase = KCS_PHASE_ABORT_ERROR1; + kcs_bmc->data_in_avail = false; + kcs_bmc->data_in_idx = 0; + break; + + default: + kcs_force_abort(kcs_bmc); + kcs_bmc->error = KCS_ILLEGAL_CONTROL_CODE; + break; + } +} + +int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc) +{ + unsigned long flags; + int ret = -ENODATA; + u8 status; + + spin_lock_irqsave(&kcs_bmc->lock, flags); + + status = read_status(kcs_bmc); + if (status & KCS_STATUS_IBF) { + if (!kcs_bmc->running) + kcs_force_abort(kcs_bmc); + else if (status & KCS_STATUS_CMD_DAT) + kcs_bmc_handle_cmd(kcs_bmc); + else + kcs_bmc_handle_data(kcs_bmc); + + ret = 0; + } + + spin_unlock_irqrestore(&kcs_bmc->lock, flags); + + return ret; +} +EXPORT_SYMBOL(kcs_bmc_handle_event); + +static inline struct kcs_bmc *to_kcs_bmc(struct file *filp) +{ + return container_of(filp->private_data, struct kcs_bmc, miscdev); +} + +static int kcs_bmc_open(struct inode *inode, struct file *filp) +{ + struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp); + int ret = 0; + + spin_lock_irq(&kcs_bmc->lock); + if (!kcs_bmc->running) + kcs_bmc->running = 1; + else + ret = -EBUSY; + spin_unlock_irq(&kcs_bmc->lock); + + return ret; +} + +static __poll_t kcs_bmc_poll(struct file *filp, poll_table *wait) +{ + struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp); + __poll_t mask = 0; + + poll_wait(filp, &kcs_bmc->queue, wait); + + spin_lock_irq(&kcs_bmc->lock); + if (kcs_bmc->data_in_avail) + mask |= EPOLLIN; + spin_unlock_irq(&kcs_bmc->lock); + + return mask; +} + +static ssize_t kcs_bmc_read(struct file *filp, char __user *buf, + size_t count, loff_t *ppos) +{ + struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp); + bool data_avail; + size_t data_len; + ssize_t ret; + + if (!(filp->f_flags & O_NONBLOCK)) + wait_event_interruptible(kcs_bmc->queue, + kcs_bmc->data_in_avail); + + mutex_lock(&kcs_bmc->mutex); + + spin_lock_irq(&kcs_bmc->lock); + data_avail = kcs_bmc->data_in_avail; + if (data_avail) { + data_len = kcs_bmc->data_in_idx; + memcpy(kcs_bmc->kbuffer, kcs_bmc->data_in, data_len); + } + spin_unlock_irq(&kcs_bmc->lock); + + if (!data_avail) { + ret = -EAGAIN; + goto out_unlock; + } + + if (count < data_len) { + pr_err("channel=%u with too large data : %zu\n", + kcs_bmc->channel, data_len); + + spin_lock_irq(&kcs_bmc->lock); + kcs_force_abort(kcs_bmc); + spin_unlock_irq(&kcs_bmc->lock); + + ret = -EOVERFLOW; + goto out_unlock; + } + + if (copy_to_user(buf, kcs_bmc->kbuffer, data_len)) { + ret = -EFAULT; + goto out_unlock; + } + + ret = data_len; + + spin_lock_irq(&kcs_bmc->lock); + if (kcs_bmc->phase == KCS_PHASE_WRITE_DONE) { + kcs_bmc->phase = KCS_PHASE_WAIT_READ; + kcs_bmc->data_in_avail = false; + kcs_bmc->data_in_idx = 0; + } else { + ret = -EAGAIN; + } + spin_unlock_irq(&kcs_bmc->lock); + +out_unlock: + mutex_unlock(&kcs_bmc->mutex); + + return ret; +} + +static ssize_t kcs_bmc_write(struct file *filp, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp); + ssize_t ret; + + /* a minimum response size '3' : netfn + cmd + ccode */ + if (count < 3 || count > KCS_MSG_BUFSIZ) + return -EINVAL; + + mutex_lock(&kcs_bmc->mutex); + + if (copy_from_user(kcs_bmc->kbuffer, buf, count)) { + ret = -EFAULT; + goto out_unlock; + } + + spin_lock_irq(&kcs_bmc->lock); + if (kcs_bmc->phase == KCS_PHASE_WAIT_READ) { + kcs_bmc->phase = KCS_PHASE_READ; + kcs_bmc->data_out_idx = 1; + kcs_bmc->data_out_len = count; + memcpy(kcs_bmc->data_out, kcs_bmc->kbuffer, count); + write_data(kcs_bmc, kcs_bmc->data_out[0]); + ret = count; + } else { + ret = -EINVAL; + } + spin_unlock_irq(&kcs_bmc->lock); + +out_unlock: + mutex_unlock(&kcs_bmc->mutex); + + return ret; +} + +static long kcs_bmc_ioctl(struct file *filp, unsigned int cmd, + unsigned long arg) +{ + struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp); + long ret = 0; + + spin_lock_irq(&kcs_bmc->lock); + + switch (cmd) { + case IPMI_BMC_IOCTL_SET_SMS_ATN: + update_status_bits(kcs_bmc, KCS_STATUS_SMS_ATN, + KCS_STATUS_SMS_ATN); + break; + + case IPMI_BMC_IOCTL_CLEAR_SMS_ATN: + update_status_bits(kcs_bmc, KCS_STATUS_SMS_ATN, + 0); + break; + + case IPMI_BMC_IOCTL_FORCE_ABORT: + kcs_force_abort(kcs_bmc); + break; + + default: + ret = -EINVAL; + break; + } + + spin_unlock_irq(&kcs_bmc->lock); + + return ret; +} + +static int kcs_bmc_release(struct inode *inode, struct file *filp) +{ + struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp); + + spin_lock_irq(&kcs_bmc->lock); + kcs_bmc->running = 0; + kcs_force_abort(kcs_bmc); + spin_unlock_irq(&kcs_bmc->lock); + + return 0; +} + +static const struct file_operations kcs_bmc_fops = { + .owner = THIS_MODULE, + .open = kcs_bmc_open, + .read = kcs_bmc_read, + .write = kcs_bmc_write, + .release = kcs_bmc_release, + .poll = kcs_bmc_poll, + .unlocked_ioctl = kcs_bmc_ioctl, +}; + +struct kcs_bmc *kcs_bmc_alloc(struct device *dev, int sizeof_priv, u32 channel) +{ + struct kcs_bmc *kcs_bmc; + + kcs_bmc = devm_kzalloc(dev, sizeof(*kcs_bmc) + sizeof_priv, GFP_KERNEL); + if (!kcs_bmc) + return NULL; + + spin_lock_init(&kcs_bmc->lock); + kcs_bmc->channel = channel; + + mutex_init(&kcs_bmc->mutex); + init_waitqueue_head(&kcs_bmc->queue); + + kcs_bmc->data_in = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL); + kcs_bmc->data_out = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL); + kcs_bmc->kbuffer = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL); + + kcs_bmc->miscdev.minor = MISC_DYNAMIC_MINOR; + kcs_bmc->miscdev.name = devm_kasprintf(dev, GFP_KERNEL, "%s%u", + DEVICE_NAME, channel); + if (!kcs_bmc->data_in || !kcs_bmc->data_out || !kcs_bmc->kbuffer || + !kcs_bmc->miscdev.name) + return NULL; + kcs_bmc->miscdev.fops = &kcs_bmc_fops; + + return kcs_bmc; +} +EXPORT_SYMBOL(kcs_bmc_alloc); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Haiyue Wang <haiyue.wang@linux.intel.com>"); +MODULE_DESCRIPTION("KCS BMC to handle the IPMI request from system software"); |