On Fri, Mar 19, 2021 at 01:27:40AM CDT, Andrew Jeffery wrote:
>Take steps towards defining a coherent API to separate the KCS device
>drivers from the userspace interface. Decreasing the coupling will
>improve the separation of concerns and enable the introduction of
>alternative userspace interfaces.
>
>For now, simply split the chardev logic out to a separate file. The code
>continues to build into the same module.
>
>Signed-off-by: Andrew Jeffery <and...@aj.id.au>
>---
> drivers/char/ipmi/Makefile            |   2 +-
> drivers/char/ipmi/kcs_bmc.c           | 423 +------------------------
> drivers/char/ipmi/kcs_bmc.h           |  10 +-
> drivers/char/ipmi/kcs_bmc_cdev_ipmi.c | 428 ++++++++++++++++++++++++++
> 4 files changed, 451 insertions(+), 412 deletions(-)
> create mode 100644 drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
>
>diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
>index 0822adc2ec41..a302bc865370 100644
>--- a/drivers/char/ipmi/Makefile
>+++ b/drivers/char/ipmi/Makefile
>@@ -22,7 +22,7 @@ obj-$(CONFIG_IPMI_SSIF) += ipmi_ssif.o
> obj-$(CONFIG_IPMI_POWERNV) += ipmi_powernv.o
> obj-$(CONFIG_IPMI_WATCHDOG) += ipmi_watchdog.o
> obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o
>-obj-$(CONFIG_IPMI_KCS_BMC) += kcs_bmc.o
>+obj-$(CONFIG_IPMI_KCS_BMC) += kcs_bmc.o kcs_bmc_cdev_ipmi.o
> obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
> obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o
> obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o
>diff --git a/drivers/char/ipmi/kcs_bmc.c b/drivers/char/ipmi/kcs_bmc.c
>index c4336c1f2d6d..ef5c48ffe74a 100644
>--- a/drivers/char/ipmi/kcs_bmc.c
>+++ b/drivers/char/ipmi/kcs_bmc.c
>@@ -3,446 +3,51 @@
>  * 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 kcs_bmc_read_data(struct kcs_bmc *kcs_bmc)
>+u8 kcs_bmc_read_data(struct kcs_bmc *kcs_bmc)
> {
>       return kcs_bmc->io_inputb(kcs_bmc, kcs_bmc->ioreg.idr);
> }
>+EXPORT_SYMBOL(kcs_bmc_read_data);
>
>-static inline void kcs_bmc_write_data(struct kcs_bmc *kcs_bmc, u8 data)
>+void kcs_bmc_write_data(struct kcs_bmc *kcs_bmc, u8 data)
> {
>       kcs_bmc->io_outputb(kcs_bmc, kcs_bmc->ioreg.odr, data);
> }
>+EXPORT_SYMBOL(kcs_bmc_write_data);
>
>-static inline u8 kcs_bmc_read_status(struct kcs_bmc *kcs_bmc)
>+u8 kcs_bmc_read_status(struct kcs_bmc *kcs_bmc)
> {
>       return kcs_bmc->io_inputb(kcs_bmc, kcs_bmc->ioreg.str);
> }
>+EXPORT_SYMBOL(kcs_bmc_read_status);
>
>-static inline void kcs_bmc_write_status(struct kcs_bmc *kcs_bmc, u8 data)
>+void kcs_bmc_write_status(struct kcs_bmc *kcs_bmc, u8 data)
> {
>       kcs_bmc->io_outputb(kcs_bmc, kcs_bmc->ioreg.str, data);
> }
>+EXPORT_SYMBOL(kcs_bmc_write_status);
>
>-static void kcs_bmc_update_status(struct kcs_bmc *kcs_bmc, u8 mask, u8 val)
>+void kcs_bmc_update_status(struct kcs_bmc *kcs_bmc, u8 mask, u8 val)
> {
>       kcs_bmc->io_updateb(kcs_bmc, kcs_bmc->ioreg.str, mask, val);
> }
>+EXPORT_SYMBOL(kcs_bmc_update_status);
>
>-static inline void set_state(struct kcs_bmc *kcs_bmc, u8 state)
>-{
>-      kcs_bmc_update_status(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);
>-      kcs_bmc_read_data(kcs_bmc);
>-      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);
>-                      kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>-                      kcs_bmc->data_in[kcs_bmc->data_in_idx++] =
>-                                              kcs_bmc_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++] =
>-                                              kcs_bmc_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 = kcs_bmc_read_data(kcs_bmc);
>-              if (data != KCS_CMD_READ_BYTE) {
>-                      set_state(kcs_bmc, ERROR_STATE);
>-                      kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>-                      break;
>-              }
>-
>-              if (kcs_bmc->data_out_idx == kcs_bmc->data_out_len) {
>-                      kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>-                      kcs_bmc->phase = KCS_PHASE_IDLE;
>-                      break;
>-              }
>-
>-              kcs_bmc_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);
>-              kcs_bmc_read_data(kcs_bmc);
>-              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);
>-              kcs_bmc_read_data(kcs_bmc);
>-              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);
>-      kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>-
>-      cmd = kcs_bmc_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_ipmi_event(struct kcs_bmc *kcs_bmc);

This declaration looks a bit out of place here; should it be in
kcs_bmc.h instead?

> 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 = kcs_bmc_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;
>+      return kcs_bmc_ipmi_event(kcs_bmc);
> }
> 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);
>-              kcs_bmc_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:
>-              kcs_bmc_update_status(kcs_bmc, KCS_STATUS_SMS_ATN, 
>KCS_STATUS_SMS_ATN);
>-              break;
>-
>-      case IPMI_BMC_IOCTL_CLEAR_SMS_ATN:
>-              kcs_bmc_update_status(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_ipmi_alloc(struct device *dev, int sizeof_priv, u32 
>channel);

Similarly here.

> 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;
>+      return kcs_bmc_ipmi_alloc(dev, sizeof_priv, channel);
> }
> EXPORT_SYMBOL(kcs_bmc_alloc);
>
>diff --git a/drivers/char/ipmi/kcs_bmc.h b/drivers/char/ipmi/kcs_bmc.h
>index 970f53892f2d..febea0c8deb4 100644
>--- a/drivers/char/ipmi/kcs_bmc.h
>+++ b/drivers/char/ipmi/kcs_bmc.h
>@@ -104,6 +104,12 @@ static inline void *kcs_bmc_priv(struct kcs_bmc *kcs_bmc)
> }
>
> int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc);
>-struct kcs_bmc *kcs_bmc_alloc(struct device *dev, int sizeof_priv,
>-                                      u32 channel);
>+struct kcs_bmc *kcs_bmc_alloc(struct device *dev, int sizeof_priv, u32 
>channel);
>+
>+u8 kcs_bmc_read_data(struct kcs_bmc *kcs_bmc);
>+void kcs_bmc_write_data(struct kcs_bmc *kcs_bmc, u8 data);
>+u8 kcs_bmc_read_status(struct kcs_bmc *kcs_bmc);
>+void kcs_bmc_write_status(struct kcs_bmc *kcs_bmc, u8 data);
>+void kcs_bmc_update_status(struct kcs_bmc *kcs_bmc, u8 mask, u8 val);
>+
> #endif /* __KCS_BMC_H__ */
>diff --git a/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c 
>b/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
>new file mode 100644
>index 000000000000..82c77994e481
>--- /dev/null
>+++ b/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
>@@ -0,0 +1,428 @@
>+// 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 void set_state(struct kcs_bmc *kcs_bmc, u8 state)
>+{
>+      kcs_bmc_update_status(kcs_bmc, KCS_STATUS_STATE_MASK,
>+                                      KCS_STATUS_STATE(state));
>+}
>+
>+static void kcs_bmc_ipmi_force_abort(struct kcs_bmc *kcs_bmc)
>+{
>+      set_state(kcs_bmc, ERROR_STATE);
>+      kcs_bmc_read_data(kcs_bmc);
>+      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_ipmi_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);
>+                      kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>+                      kcs_bmc->data_in[kcs_bmc->data_in_idx++] =
>+                                              kcs_bmc_read_data(kcs_bmc);
>+              } else {
>+                      kcs_bmc_ipmi_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++] =
>+                                              kcs_bmc_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_bmc_ipmi_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 = kcs_bmc_read_data(kcs_bmc);
>+              if (data != KCS_CMD_READ_BYTE) {
>+                      set_state(kcs_bmc, ERROR_STATE);
>+                      kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>+                      break;
>+              }
>+
>+              if (kcs_bmc->data_out_idx == kcs_bmc->data_out_len) {
>+                      kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>+                      kcs_bmc->phase = KCS_PHASE_IDLE;
>+                      break;
>+              }
>+
>+              kcs_bmc_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);
>+              kcs_bmc_read_data(kcs_bmc);
>+              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);
>+              kcs_bmc_read_data(kcs_bmc);
>+              kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>+              kcs_bmc->phase = KCS_PHASE_IDLE;
>+              break;
>+
>+      default:
>+              kcs_bmc_ipmi_force_abort(kcs_bmc);
>+              break;
>+      }
>+}
>+
>+static void kcs_bmc_ipmi_handle_cmd(struct kcs_bmc *kcs_bmc)
>+{
>+      u8 cmd;
>+
>+      set_state(kcs_bmc, WRITE_STATE);
>+      kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA);
>+
>+      cmd = kcs_bmc_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_bmc_ipmi_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_bmc_ipmi_force_abort(kcs_bmc);
>+              kcs_bmc->error = KCS_ILLEGAL_CONTROL_CODE;
>+              break;
>+      }
>+}
>+
>+int kcs_bmc_ipmi_event(struct kcs_bmc *kcs_bmc);

Another instance...

>+int kcs_bmc_ipmi_event(struct kcs_bmc *kcs_bmc)
>+{
>+      unsigned long flags;
>+      int ret = -ENODATA;
>+      u8 status;
>+
>+      spin_lock_irqsave(&kcs_bmc->lock, flags);
>+
>+      status = kcs_bmc_read_status(kcs_bmc);
>+      if (status & KCS_STATUS_IBF) {
>+              if (!kcs_bmc->running)
>+                      kcs_bmc_ipmi_force_abort(kcs_bmc);
>+              else if (status & KCS_STATUS_CMD_DAT)
>+                      kcs_bmc_ipmi_handle_cmd(kcs_bmc);
>+              else
>+                      kcs_bmc_ipmi_handle_data(kcs_bmc);
>+
>+              ret = 0;
>+      }
>+
>+      spin_unlock_irqrestore(&kcs_bmc->lock, flags);
>+
>+      return ret;
>+}
>+EXPORT_SYMBOL(kcs_bmc_ipmi_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_ipmi_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_ipmi_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_ipmi_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_bmc_ipmi_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_ipmi_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);
>+              kcs_bmc_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_ipmi_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:
>+              kcs_bmc_update_status(kcs_bmc, KCS_STATUS_SMS_ATN, 
>KCS_STATUS_SMS_ATN);
>+              break;
>+
>+      case IPMI_BMC_IOCTL_CLEAR_SMS_ATN:
>+              kcs_bmc_update_status(kcs_bmc, KCS_STATUS_SMS_ATN, 0);
>+              break;
>+
>+      case IPMI_BMC_IOCTL_FORCE_ABORT:
>+              kcs_bmc_ipmi_force_abort(kcs_bmc);
>+              break;
>+
>+      default:
>+              ret = -EINVAL;
>+              break;
>+      }
>+
>+      spin_unlock_irq(&kcs_bmc->lock);
>+
>+      return ret;
>+}
>+
>+static int kcs_bmc_ipmi_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_bmc_ipmi_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_ipmi_open,
>+      .read           = kcs_bmc_ipmi_read,
>+      .write          = kcs_bmc_ipmi_write,
>+      .release        = kcs_bmc_ipmi_release,
>+      .poll           = kcs_bmc_ipmi_poll,
>+      .unlocked_ioctl = kcs_bmc_ipmi_ioctl,
>+};
>+
>+struct kcs_bmc *kcs_bmc_ipmi_alloc(struct device *dev, int sizeof_priv, u32 
>channel);

Here too.

>+struct kcs_bmc *kcs_bmc_ipmi_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_ipmi_alloc);
>+
>+MODULE_LICENSE("GPL v2");
>+MODULE_AUTHOR("Haiyue Wang <haiyue.w...@linux.intel.com>");
>+MODULE_DESCRIPTION("KCS BMC to handle the IPMI request from system software");
>-- 
>2.27.0
>

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