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// SPDX-License-Identifier: GPL-2.0
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/fsi-occ.h>
#include <linux/i2c.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <asm/unaligned.h>
#include "common.h"
#define OCC_TIMEOUT_MS 1000
#define OCC_CMD_IN_PRG_WAIT_MS 50
/* OCB (on-chip control bridge - interface to OCC) registers */
#define OCB_DATA1 0x6B035
#define OCB_ADDR 0x6B070
#define OCB_DATA3 0x6B075
/* OCC SRAM address space */
#define OCC_SRAM_ADDR_CMD 0xFFFF6000
#define OCC_SRAM_ADDR_RESP 0xFFFF7000
#define OCC_DATA_ATTN 0x20010000
struct p8_i2c_occ {
struct occ occ;
struct i2c_client *client;
};
#define to_p8_i2c_occ(x) container_of((x), struct p8_i2c_occ, occ)
static int p8_i2c_occ_getscom(struct i2c_client *client, u32 address, u8 *data)
{
ssize_t rc;
__be64 buf;
struct i2c_msg msgs[2];
/* p8 i2c slave requires shift */
address <<= 1;
msgs[0].addr = client->addr;
msgs[0].flags = client->flags & I2C_M_TEN;
msgs[0].len = sizeof(u32);
/* address is a scom address; bus-endian */
msgs[0].buf = (char *)&address;
/* data from OCC is big-endian */
msgs[1].addr = client->addr;
msgs[1].flags = (client->flags & I2C_M_TEN) | I2C_M_RD;
msgs[1].len = sizeof(u64);
msgs[1].buf = (char *)&buf;
rc = i2c_transfer(client->adapter, msgs, 2);
if (rc < 0)
return rc;
*(u64 *)data = be64_to_cpu(buf);
return 0;
}
static int p8_i2c_occ_putscom(struct i2c_client *client, u32 address, u8 *data)
{
u32 buf[3];
ssize_t rc;
/* p8 i2c slave requires shift */
address <<= 1;
/* address is bus-endian; data passed through from user as-is */
buf[0] = address;
memcpy(&buf[1], &data[4], sizeof(u32));
memcpy(&buf[2], data, sizeof(u32));
rc = i2c_master_send(client, (const char *)buf, sizeof(buf));
if (rc < 0)
return rc;
else if (rc != sizeof(buf))
return -EIO;
return 0;
}
static int p8_i2c_occ_putscom_u32(struct i2c_client *client, u32 address,
u32 data0, u32 data1)
{
u8 buf[8];
memcpy(buf, &data0, 4);
memcpy(buf + 4, &data1, 4);
return p8_i2c_occ_putscom(client, address, buf);
}
static int p8_i2c_occ_putscom_be(struct i2c_client *client, u32 address,
u8 *data)
{
__be32 data0, data1;
memcpy(&data0, data, 4);
memcpy(&data1, data + 4, 4);
return p8_i2c_occ_putscom_u32(client, address, be32_to_cpu(data0),
be32_to_cpu(data1));
}
static int p8_i2c_occ_send_cmd(struct occ *occ, u8 *cmd)
{
int i, rc;
unsigned long start;
u16 data_length;
const unsigned long timeout = msecs_to_jiffies(OCC_TIMEOUT_MS);
const long wait_time = msecs_to_jiffies(OCC_CMD_IN_PRG_WAIT_MS);
struct p8_i2c_occ *ctx = to_p8_i2c_occ(occ);
struct i2c_client *client = ctx->client;
struct occ_response *resp = &occ->resp;
start = jiffies;
/* set sram address for command */
rc = p8_i2c_occ_putscom_u32(client, OCB_ADDR, OCC_SRAM_ADDR_CMD, 0);
if (rc)
return rc;
/* write command (expected to already be BE), we need bus-endian... */
rc = p8_i2c_occ_putscom_be(client, OCB_DATA3, cmd);
if (rc)
return rc;
/* trigger OCC attention */
rc = p8_i2c_occ_putscom_u32(client, OCB_DATA1, OCC_DATA_ATTN, 0);
if (rc)
return rc;
do {
/* set sram address for response */
rc = p8_i2c_occ_putscom_u32(client, OCB_ADDR,
OCC_SRAM_ADDR_RESP, 0);
if (rc)
return rc;
rc = p8_i2c_occ_getscom(client, OCB_DATA3, (u8 *)resp);
if (rc)
return rc;
/* wait for OCC */
if (resp->return_status == OCC_RESP_CMD_IN_PRG) {
rc = -EALREADY;
if (time_after(jiffies, start + timeout))
break;
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(wait_time);
}
} while (rc);
/* check the OCC response */
switch (resp->return_status) {
case OCC_RESP_CMD_IN_PRG:
rc = -ETIMEDOUT;
break;
case OCC_RESP_SUCCESS:
rc = 0;
break;
case OCC_RESP_CMD_INVAL:
case OCC_RESP_CMD_LEN_INVAL:
case OCC_RESP_DATA_INVAL:
case OCC_RESP_CHKSUM_ERR:
rc = -EINVAL;
break;
case OCC_RESP_INT_ERR:
case OCC_RESP_BAD_STATE:
case OCC_RESP_CRIT_EXCEPT:
case OCC_RESP_CRIT_INIT:
case OCC_RESP_CRIT_WATCHDOG:
case OCC_RESP_CRIT_OCB:
case OCC_RESP_CRIT_HW:
rc = -EREMOTEIO;
break;
default:
rc = -EPROTO;
}
if (rc < 0)
return rc;
data_length = get_unaligned_be16(&resp->data_length);
if (data_length > OCC_RESP_DATA_BYTES)
return -EMSGSIZE;
/* fetch the rest of the response data */
for (i = 8; i < data_length + 7; i += 8) {
rc = p8_i2c_occ_getscom(client, OCB_DATA3, ((u8 *)resp) + i);
if (rc)
return rc;
}
return 0;
}
static int p8_i2c_occ_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct occ *occ;
struct p8_i2c_occ *ctx = devm_kzalloc(&client->dev, sizeof(*ctx),
GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->client = client;
occ = &ctx->occ;
occ->bus_dev = &client->dev;
dev_set_drvdata(&client->dev, occ);
occ->powr_sample_time_us = 250;
occ->poll_cmd_data = 0x10; /* P8 OCC poll data */
occ->send_cmd = p8_i2c_occ_send_cmd;
return occ_setup(occ, "p8_occ");
}
static const struct of_device_id p8_i2c_occ_of_match[] = {
{ .compatible = "ibm,p8-occ-hwmon" },
{}
};
MODULE_DEVICE_TABLE(of, p8_i2c_occ_of_match);
static struct i2c_driver p8_i2c_occ_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "occ-hwmon",
.of_match_table = p8_i2c_occ_of_match,
},
.probe = p8_i2c_occ_probe,
};
module_i2c_driver(p8_i2c_occ_driver);
MODULE_AUTHOR("Eddie James <eajames@linux.ibm.com>");
MODULE_DESCRIPTION("BMC P8 OCC hwmon driver");
MODULE_LICENSE("GPL");
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