Re: [PATCH arm/aspeed/ast2500 v4 1/2] ipmi: add a KCS IPMI BMC driver
From: Corey Minyard
Date: Thu Feb 01 2018 - 20:10:31 EST
On 02/01/2018 06:28 PM, Haiyue Wang wrote:
---
v3->v4
- Change to accept WRITE_START any time.
v2->v3
- Update the KCS phase state machine.
- Fix the race condition of read/write.
v1->v2
- Divide the driver into two parts, one handles the BMC KCS IPMI 2.0 state;
the other handles the BMC KCS controller such as AST2500 IO accessing.
- Use the spin lock APIs to handle the device file operations and BMC chip
IRQ inferface for accessing the same KCS BMC data structure.
- Enhanced the phases handling of the KCS BMC.
- Unified the IOCTL definition for IPMI BMC, it will be used by KCS and BT.
Provides a device driver for the KCS (Keyboard Controller Style)
IPMI interface which meets the requirement of the BMC (Baseboard
Management Controllers) side for handling the IPMI request from
host system software.
I loaded this in, tried a compile on x86_64, and got the following:
In file included from ../drivers/char/ipmi/kcs_bmc.c:15:0:
../drivers/char/ipmi/kcs_bmc.h: In function âkcs_bmc_privâ:
../drivers/char/ipmi/kcs_bmc.h:100:9: warning: return discards âconstâ
qualifier from pointer target type [-Wdiscarded-qualifiers]
 return kcs_bmc->priv;
ÂÂÂÂÂÂÂÂ ^
In file included from ../include/linux/printk.h:7:0,
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ from ../include/linux/kernel.h:14,
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ from ../include/asm-generic/bug.h:18,
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ from ../arch/x86/include/asm/bug.h:82,
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ from ../include/linux/bug.h:5,
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ from ../include/linux/io.h:23,
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ from ../drivers/char/ipmi/kcs_bmc.c:7:
../drivers/char/ipmi/kcs_bmc.c: In function âkcs_bmc_readâ:
../include/linux/kern_levels.h:5:18: warning: format â%uâ expects
argument of type âunsigned intâ, but argument 3 has type âsize_t {aka
long unsigned int}â [-Wformat=]
Â#define KERN_SOH "\001"Â /* ASCII Start Of Header */
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ ^
../include/linux/kern_levels.h:11:18: note: in expansion of macro âKERN_SOHâ
Â#define KERN_ERR KERN_SOH "3" /* error conditions */
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ ^
../include/linux/printk.h:301:9: note: in expansion of macro âKERN_ERRâ
 printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
ÂÂÂÂÂÂÂÂ ^
../drivers/char/ipmi/kcs_bmc.c:307:3: note: in expansion of macro âpr_errâ
ÂÂ pr_err("channel=%u with too large data : %u\n",
ÂÂ ^
In file included from ../drivers/char/ipmi/kcs_bmc_aspeed.c:20:0:
../drivers/char/ipmi/kcs_bmc.h: In function âkcs_bmc_privâ:
../drivers/char/ipmi/kcs_bmc.h:100:9: warning: return discards âconstâ
qualifier from pointer target type [-Wdiscarded-qualifiers]
 return kcs_bmc->priv;
ÂÂÂÂÂÂÂÂ ^
So that needs to be fixed before it goes in.
Also, since you are respinning, can you make ASPEED_KCS_IPMI_BMC select
IPMI_KCS_BMC, like:
diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index bc2568a..d34f40e 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -99,16 +99,11 @@ config IPMI_POWEROFF
Âendif # IPMI_HANDLER
Âconfig IPMI_KCS_BMC
-ÂÂÂÂÂÂ tristate 'IPMI KCS BMC Interface'
-ÂÂÂÂÂÂ help
-ÂÂÂÂÂÂÂÂ Provides a device driver for the KCS (Keyboard Controller Style)
-ÂÂÂÂÂÂÂÂ IPMI interface which meets the requirement of the BMC (Baseboard
-ÂÂÂÂÂÂÂÂ Management Controllers) side for handling the IPMI request from
-ÂÂÂÂÂÂÂÂ host system software.
+ÂÂÂÂÂÂ tristate
Âconfig ASPEED_KCS_IPMI_BMC
ÂÂÂÂÂÂÂ depends on ARCH_ASPEED || COMPILE_TEST
-ÂÂÂÂÂÂ depends on IPMI_KCS_BMC
+ÂÂÂÂÂÂ select IPMI_KCS_BMC
ÂÂÂÂÂÂÂ select REGMAP_MMIO
ÂÂÂÂÂÂÂ tristate "Aspeed KCS IPMI BMC driver"
ÂÂÂÂÂÂÂ help
It doesn't make much sense to have IPMI_KCS_BMC on its own. I was going
to do this till I saw the compiler error.
-corey
Signed-off-by: Haiyue Wang <haiyue.wang@xxxxxxxxxxxxxxx>
---
drivers/char/ipmi/Kconfig | 8 +
drivers/char/ipmi/Makefile | 1 +
drivers/char/ipmi/kcs_bmc.c | 464 ++++++++++++++++++++++++++++++++++++++++++
drivers/char/ipmi/kcs_bmc.h | 106 ++++++++++
include/uapi/linux/ipmi_bmc.h | 14 ++
5 files changed, 593 insertions(+)
create mode 100644 drivers/char/ipmi/kcs_bmc.c
create mode 100644 drivers/char/ipmi/kcs_bmc.h
create mode 100644 include/uapi/linux/ipmi_bmc.h
diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index 3544abc..aa9bcb1 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -96,6 +96,14 @@ config IPMI_POWEROFF
endif # IPMI_HANDLER
+config IPMI_KCS_BMC
+ tristate 'IPMI KCS BMC Interface'
+ help
+ Provides a device driver for the KCS (Keyboard Controller Style)
+ IPMI interface which meets the requirement of the BMC (Baseboard
+ Management Controllers) side for handling the IPMI request from
+ host system software.
+
config ASPEED_BT_IPMI_BMC
depends on ARCH_ASPEED || COMPILE_TEST
depends on REGMAP && REGMAP_MMIO && MFD_SYSCON
diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
index 33b899f..2abccb3 100644
--- a/drivers/char/ipmi/Makefile
+++ b/drivers/char/ipmi/Makefile
@@ -21,4 +21,5 @@ 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_ASPEED_BT_IPMI_BMC) += bt-bmc.o
diff --git a/drivers/char/ipmi/kcs_bmc.c b/drivers/char/ipmi/kcs_bmc.c
new file mode 100644
index 0000000..d1751b4
--- /dev/null
+++ b/drivers/char/ipmi/kcs_bmc.c
@@ -0,0 +1,464 @@
+// 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 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;
+
+ 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 = 0;
+ u8 status;
+
+ spin_lock_irqsave(&kcs_bmc->lock, flags);
+
+ if (!kcs_bmc->running) {
+ kcs_force_abort(kcs_bmc);
+ ret = -ENODEV;
+ goto out_unlock;
+ }
+
+ status = read_status(kcs_bmc) & (KCS_STATUS_IBF | KCS_STATUS_CMD_DAT);
+
+ switch (status) {
+ case KCS_STATUS_IBF | KCS_STATUS_CMD_DAT:
+ kcs_bmc_handle_cmd(kcs_bmc);
+ break;
+
+ case KCS_STATUS_IBF:
+ kcs_bmc_handle_data(kcs_bmc);
+ break;
+
+ default:
+ ret = -ENODATA;
+ break;
+ }
+
+out_unlock:
+ spin_unlock_irqrestore(&kcs_bmc->lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL(kcs_bmc_handle_event);
+
+static inline struct kcs_bmc *file_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 = file_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 unsigned int kcs_bmc_poll(struct file *filp, poll_table *wait)
+{
+ struct kcs_bmc *kcs_bmc = file_to_kcs_bmc(filp);
+ unsigned int mask = 0;
+
+ poll_wait(filp, &kcs_bmc->queue, wait);
+
+ spin_lock_irq(&kcs_bmc->lock);
+ if (kcs_bmc->data_in_avail)
+ mask |= POLLIN;
+ spin_unlock_irq(&kcs_bmc->lock);
+
+ return mask;
+}
+
+static ssize_t kcs_bmc_read(struct file *filp, char *buf,
+ size_t count, loff_t *offset)
+{
+ struct kcs_bmc *kcs_bmc = file_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 : %u\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 *buf,
+ size_t count, loff_t *offset)
+{
+ struct kcs_bmc *kcs_bmc = file_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 = file_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 = file_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;
+
+ dev_set_name(dev, "ipmi-kcs%u", channel);
+
+ 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);
+ if (!kcs_bmc->data_in || !kcs_bmc->data_out || !kcs_bmc->kbuffer)
+ return NULL;
+
+ kcs_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
+ kcs_bmc->miscdev.name = dev_name(dev);
+ 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@xxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("KCS BMC to handle the IPMI request from system software");
diff --git a/drivers/char/ipmi/kcs_bmc.h b/drivers/char/ipmi/kcs_bmc.h
new file mode 100644
index 0000000..f2ecbe6
--- /dev/null
+++ b/drivers/char/ipmi/kcs_bmc.h
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2015-2018, Intel Corporation.
+
+#ifndef __KCS_BMC_H__
+#define __KCS_BMC_H__
+
+#include <linux/miscdevice.h>
+
+/* Different phases of the KCS BMC module :
+ * KCS_PHASE_IDLE :
+ * BMC should not be expecting nor sending any data.
+ * KCS_PHASE_WRITE_START :
+ * BMC is receiving a WRITE_START command from system software.
+ * KCS_PHASE_WRITE_DATA :
+ * BMC is receiving a data byte from system software.
+ * KCS_PHASE_WRITE_END_CMD :
+ * BMC is waiting a last data byte from system software.
+ * KCS_PHASE_WRITE_DONE :
+ * BMC has received the whole request from system software.
+ * KCS_PHASE_WAIT_READ :
+ * BMC is waiting the response from the upper IPMI service.
+ * KCS_PHASE_READ :
+ * BMC is transferring the response to system software.
+ * KCS_PHASE_ABORT_ERROR1 :
+ * BMC is waiting error status request from system software.
+ * KCS_PHASE_ABORT_ERROR2 :
+ * BMC is waiting for idle status afer error from system software.
+ * KCS_PHASE_ERROR :
+ * BMC has detected a protocol violation at the interface level.
+ */
+enum kcs_phases {
+ KCS_PHASE_IDLE,
+
+ KCS_PHASE_WRITE_START,
+ KCS_PHASE_WRITE_DATA,
+ KCS_PHASE_WRITE_END_CMD,
+ KCS_PHASE_WRITE_DONE,
+
+ KCS_PHASE_WAIT_READ,
+ KCS_PHASE_READ,
+
+ KCS_PHASE_ABORT_ERROR1,
+ KCS_PHASE_ABORT_ERROR2,
+ KCS_PHASE_ERROR
+};
+
+/* IPMI 2.0 - Table 9-4, KCS Interface Status Codes */
+enum kcs_errors {
+ KCS_NO_ERROR = 0x00,
+ KCS_ABORTED_BY_COMMAND = 0x01,
+ KCS_ILLEGAL_CONTROL_CODE = 0x02,
+ KCS_LENGTH_ERROR = 0x06,
+ KCS_UNSPECIFIED_ERROR = 0xFF
+};
+
+/* IPMI 2.0 - 9.5, KCS Interface Registers
+ * @idr : Input Data Register
+ * @odr : Output Data Register
+ * @str : Status Register
+ */
+struct kcs_ioreg {
+ u32 idr;
+ u32 odr;
+ u32 str;
+};
+
+struct kcs_bmc {
+ spinlock_t lock;
+
+ u32 channel;
+ int running;
+
+ /* Setup by BMC KCS controller driver */
+ struct kcs_ioreg ioreg;
+ u8 (*io_inputb)(struct kcs_bmc *kcs_bmc, u32 reg);
+ void (*io_outputb)(struct kcs_bmc *kcs_bmc, u32 reg, u8 b);
+
+ enum kcs_phases phase;
+ enum kcs_errors error;
+
+ wait_queue_head_t queue;
+ bool data_in_avail;
+ int data_in_idx;
+ u8 *data_in;
+
+ int data_out_idx;
+ int data_out_len;
+ u8 *data_out;
+
+ struct mutex mutex;
+ u8 *kbuffer;
+
+ struct miscdevice miscdev;
+
+ unsigned long priv[];
+};
+
+static inline void *kcs_bmc_priv(const struct kcs_bmc *kcs_bmc)
+{
+ return kcs_bmc->priv;
+}
+
+int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc);
+struct kcs_bmc *kcs_bmc_alloc(struct device *dev, int sizeof_priv,
+ u32 channel);
+#endif
diff --git a/include/uapi/linux/ipmi_bmc.h b/include/uapi/linux/ipmi_bmc.h
new file mode 100644
index 0000000..2f9f97e
--- /dev/null
+++ b/include/uapi/linux/ipmi_bmc.h
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2015-2018, Intel Corporation.
+
+#ifndef _UAPI_LINUX_IPMI_BMC_H
+#define _UAPI_LINUX_IPMI_BMC_H
+
+#include <linux/ioctl.h>
+
+#define __IPMI_BMC_IOCTL_MAGIC 0xB1
+#define IPMI_BMC_IOCTL_SET_SMS_ATN _IO(__IPMI_BMC_IOCTL_MAGIC, 0x00)
+#define IPMI_BMC_IOCTL_CLEAR_SMS_ATN _IO(__IPMI_BMC_IOCTL_MAGIC, 0x01)
+#define IPMI_BMC_IOCTL_FORCE_ABORT _IO(__IPMI_BMC_IOCTL_MAGIC, 0x02)
+
+#endif /* _UAPI_LINUX_KCS_BMC_H */