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hwmon (occ): Add command transport method for P8 and P9
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For the P8 OCC, add the procedure to send a command to the OCC over I2C
bus. This involves writing the OCC command registers with serial
communication operations (SCOMs) interpreted by the I2C slave. For the
P9 OCC, add a procedure to use the OCC in-kernel API to send a command
to the OCC through the SBE.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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Eddie James authored and Guenter Roeck committed Dec 16, 2018
1 parent 5b5513b commit 88be37c
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185 changes: 184 additions & 1 deletion drivers/hwmon/occ/p8_i2c.c
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Expand Up @@ -2,21 +2,204 @@

#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)
{
return -EOPNOTSUPP;
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,
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38 changes: 37 additions & 1 deletion drivers/hwmon/occ/p9_sbe.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@

#include <linux/device.h>
#include <linux/errno.h>
#include <linux/fsi-occ.h>
#include <linux/module.h>
#include <linux/platform_device.h>

Expand All @@ -16,7 +17,42 @@ struct p9_sbe_occ {

static int p9_sbe_occ_send_cmd(struct occ *occ, u8 *cmd)
{
return -EOPNOTSUPP;
struct occ_response *resp = &occ->resp;
struct p9_sbe_occ *ctx = to_p9_sbe_occ(occ);
size_t resp_len = sizeof(*resp);
int rc;

rc = fsi_occ_submit(ctx->sbe, cmd, 8, resp, &resp_len);
if (rc < 0)
return rc;

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;
}

return rc;
}

static int p9_sbe_occ_probe(struct platform_device *pdev)
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