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// 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;
/* fall through */
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->
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