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Subject[PATCH v3 06/12] hwmon (occ): Add command transport method for P8 and P9
Date
From: "Edward A. James" <eajames@us.ibm.com>

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 engine.

Signed-off-by: Edward A. James <eajames@us.ibm.com>
---
drivers/hwmon/occ/p8_i2c.c | 185 ++++++++++++++++++++++++++++++++++++++++++++-
drivers/hwmon/occ/p9_sbe.c | 95 ++++++++++++++++++++++-
2 files changed, 278 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/occ/p8_i2c.c b/drivers/hwmon/occ/p8_i2c.c
index 025471f..8032c0b 100644
--- a/drivers/hwmon/occ/p8_i2c.c
+++ b/drivers/hwmon/occ/p8_i2c.c
@@ -9,11 +9,29 @@

#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;
@@ -21,9 +39,174 @@ struct p8_i2c_occ {

#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 int wait_time = msecs_to_jiffies(OCC_CMD_IN_PRG_WAIT_MS);
+ struct p8_i2c_occ *p8_i2c_occ = to_p8_i2c_occ(occ);
+ struct i2c_client *client = p8_i2c_occ->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,
diff --git a/drivers/hwmon/occ/p9_sbe.c b/drivers/hwmon/occ/p9_sbe.c
index 58c3bb2..be3a469 100644
--- a/drivers/hwmon/occ/p9_sbe.c
+++ b/drivers/hwmon/occ/p9_sbe.c
@@ -9,21 +9,102 @@

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

#include "common.h"

struct p9_sbe_occ {
struct occ occ;
struct device *sbe;
+
+ /*
+ * Pointer to occ device client. We store this so that we can cancel
+ * the client operations in remove() if necessary. We only need one
+ * pointer since we do one OCC operation (open, write, read, close) at
+ * a time (access to p9_sbe_occ_send_cmd is locked in the common code
+ * with occ.lock).
+ */
+ struct occ_client *client;
+
+ /*
+ * This lock controls access to the client pointer and ensures atomic
+ * open, close and NULL assignment. This prevents simultaneous opening
+ * and closing of the client, or closing multiple times.
+ */
+ spinlock_t lock;
};

#define to_p9_sbe_occ(x) container_of((x), struct p9_sbe_occ, occ)

+static void p9_sbe_occ_close_client(struct p9_sbe_occ *occ)
+{
+ unsigned long flags;
+ struct occ_client *tmp_client;
+
+ spin_lock_irqsave(&occ->lock, flags);
+ tmp_client = occ->client;
+ occ->client = NULL;
+ occ_drv_release(tmp_client);
+ spin_unlock_irqrestore(&occ->lock, flags);
+}
+
static int p9_sbe_occ_send_cmd(struct occ *occ, u8 *cmd)
{
- return -EOPNOTSUPP;
+ int rc;
+ unsigned long flags;
+ struct occ_response *resp = &occ->resp;
+ struct p9_sbe_occ *p9_sbe_occ = to_p9_sbe_occ(occ);
+
+ spin_lock_irqsave(&p9_sbe_occ->lock, flags);
+ if (p9_sbe_occ->sbe)
+ p9_sbe_occ->client = occ_drv_open(p9_sbe_occ->sbe, 0);
+ spin_unlock_irqrestore(&p9_sbe_occ->lock, flags);
+
+ if (!p9_sbe_occ->client)
+ return -ENODEV;
+
+ /* skip first byte (sequence number), OCC driver handles it */
+ rc = occ_drv_write(p9_sbe_occ->client, (const char *)&cmd[1], 7);
+ if (rc < 0)
+ goto err;
+
+ rc = occ_drv_read(p9_sbe_occ->client, (char *)resp, sizeof(*resp));
+ if (rc < 0)
+ goto err;
+
+ /* 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;
+ }
+
+err:
+ p9_sbe_occ_close_client(p9_sbe_occ);
+ return rc;
}

static int p9_sbe_occ_probe(struct platform_device *pdev)
@@ -46,6 +127,17 @@ static int p9_sbe_occ_probe(struct platform_device *pdev)
return occ_setup(occ, "p9_occ");
}

+static int p9_sbe_occ_remove(struct platform_device *pdev)
+{
+ struct occ *occ = platform_get_drvdata(pdev);
+ struct p9_sbe_occ *p9_sbe_occ = to_p9_sbe_occ(occ);
+
+ p9_sbe_occ->sbe = NULL;
+ p9_sbe_occ_close_client(p9_sbe_occ);
+
+ return 0;
+}
+
static const struct of_device_id p9_sbe_occ_of_match[] = {
{ .compatible = "ibm,p9-occ-hwmon" },
{ },
@@ -57,6 +149,7 @@ static int p9_sbe_occ_probe(struct platform_device *pdev)
.of_match_table = p9_sbe_occ_of_match,
},
.probe = p9_sbe_occ_probe,
+ .remove = p9_sbe_occ_remove,
};

module_platform_driver(p9_sbe_occ_driver);
--
1.8.3.1
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