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path: root/drivers/hwmon/occ/p8_i2c.c
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Diffstat (limited to 'drivers/hwmon/occ/p8_i2c.c')
-rw-r--r--drivers/hwmon/occ/p8_i2c.c257
1 files changed, 257 insertions, 0 deletions
diff --git a/drivers/hwmon/occ/p8_i2c.c b/drivers/hwmon/occ/p8_i2c.c
new file mode 100644
index 0000000000..06095975f5
--- /dev/null
+++ b/drivers/hwmon/occ/p8_i2c.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright IBM Corp 2019
+
+#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, size_t len)
+{
+ __be32 data0 = 0, data1 = 0;
+
+ memcpy(&data0, data, min_t(size_t, len, 4));
+ if (len > 4) {
+ len -= 4;
+ memcpy(&data1, data + 4, min_t(size_t, len, 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, size_t len,
+ void *resp, size_t resp_len)
+{
+ 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 *or = (struct occ_response *)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, len);
+ 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 (or->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 (or->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(&or->data_length);
+ if ((data_length + 7) > resp_len)
+ 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)
+{
+ 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);
+}
+
+static void p8_i2c_occ_remove(struct i2c_client *client)
+{
+ struct occ *occ = dev_get_drvdata(&client->dev);
+
+ occ_shutdown(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,
+ .remove = p8_i2c_occ_remove,
+};
+
+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");