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- // 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_new = p8_i2c_occ_probe,
- .remove = p8_i2c_occ_remove,
- };
- module_i2c_driver(p8_i2c_occ_driver);
- MODULE_AUTHOR("Eddie James <[email protected]>");
- MODULE_DESCRIPTION("BMC P8 OCC hwmon driver");
- MODULE_LICENSE("GPL");
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