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Message-Id: <20230119174714.1486042-3-eajames@linux.ibm.com>
Date: Thu, 19 Jan 2023 11:47:14 -0600
From: Eddie James <eajames@...ux.ibm.com>
To: linux-fsi@...ts.ozlabs.org
Cc: linux-kernel@...r.kernel.org, jk@...abs.org, joel@....id.au,
alistair@...ple.id.au, devicetree@...r.kernel.org,
robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
Eddie James <eajames@...ux.ibm.com>
Subject: [PATCH 2/2] fsi: Add IBM I2C Responder virtual FSI master
The I2C Responder (I2CR) is an I2C device that translates I2C commands
to CFAM or SCOM operations, effectively implementing an FSI master and
bus.
Signed-off-by: Eddie James <eajames@...ux.ibm.com>
---
drivers/fsi/Kconfig | 9 +
drivers/fsi/Makefile | 1 +
drivers/fsi/fsi-master-i2cr.c | 225 +++++++++++++++++++++++++
include/trace/events/fsi_master_i2cr.h | 96 +++++++++++
4 files changed, 331 insertions(+)
create mode 100644 drivers/fsi/fsi-master-i2cr.c
create mode 100644 include/trace/events/fsi_master_i2cr.h
diff --git a/drivers/fsi/Kconfig b/drivers/fsi/Kconfig
index e6668a869913..999be82720c5 100644
--- a/drivers/fsi/Kconfig
+++ b/drivers/fsi/Kconfig
@@ -62,6 +62,15 @@ config FSI_MASTER_ASPEED
Enable it for your BMC kernel in an OpenPower or IBM Power system.
+config FSI_MASTER_I2CR
+ tristate "IBM I2C Responder virtual FSI master"
+ depends on I2C
+ help
+ This option enables a virtual FSI master in order to access a CFAM
+ behind an IBM I2C Responder (I2CR) chip. The I2CR is an I2C device
+ that translates I2C commands to CFAM or SCOM operations, effectively
+ implementing an FSI master and bus.
+
config FSI_SCOM
tristate "SCOM FSI client device driver"
help
diff --git a/drivers/fsi/Makefile b/drivers/fsi/Makefile
index da218a1ad8e1..34dbaa1c452e 100644
--- a/drivers/fsi/Makefile
+++ b/drivers/fsi/Makefile
@@ -4,6 +4,7 @@ obj-$(CONFIG_FSI) += fsi-core.o
obj-$(CONFIG_FSI_MASTER_HUB) += fsi-master-hub.o
obj-$(CONFIG_FSI_MASTER_ASPEED) += fsi-master-aspeed.o
obj-$(CONFIG_FSI_MASTER_GPIO) += fsi-master-gpio.o
+obj-$(CONFIG_FSI_MASTER_I2CR) += fsi-master-i2cr.o
obj-$(CONFIG_FSI_MASTER_AST_CF) += fsi-master-ast-cf.o
obj-$(CONFIG_FSI_SCOM) += fsi-scom.o
obj-$(CONFIG_FSI_SBEFIFO) += fsi-sbefifo.o
diff --git a/drivers/fsi/fsi-master-i2cr.c b/drivers/fsi/fsi-master-i2cr.c
new file mode 100644
index 000000000000..d19ac96c0a83
--- /dev/null
+++ b/drivers/fsi/fsi-master-i2cr.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) IBM Corporation 2023 */
+
+#include <linux/device.h>
+#include <linux/fsi.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/mutex.h>
+
+#include "fsi-master.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/fsi_master_i2cr.h>
+
+#define I2CR_ADDRESS_CFAM(a) ((a) >> 2)
+#define I2CR_STATUS 0x30001
+#define I2CR_STATUS_ERR BIT_ULL(61)
+#define I2CR_ERROR 0x30002
+
+struct fsi_master_i2cr {
+ struct fsi_master master;
+ struct mutex lock; /* protect HW access */
+ struct i2c_client *client;
+};
+
+static bool i2cr_check_parity(u32 v, bool parity)
+{
+ u32 i;
+
+ for (i = 0; i < 32; ++i) {
+ if (v & (1 << i))
+ parity = !parity;
+ }
+
+ return parity;
+}
+
+static __be32 i2cr_get_command(u32 address, bool parity)
+{
+ __be32 command;
+
+ address <<= 1;
+
+ if (i2cr_check_parity(address, parity))
+ address |= 1;
+
+ command = cpu_to_be32(address);
+ trace_i2cr_command((__force uint32_t)command);
+
+ return command;
+}
+
+static int i2cr_transfer(struct i2c_client *client, u32 address, __be64 *data)
+{
+ struct i2c_msg msgs[2];
+ __be32 command;
+ int ret;
+
+ command = i2cr_get_command(address, true);
+ msgs[0].addr = client->addr;
+ msgs[0].flags = 0;
+ msgs[0].len = sizeof(command);
+ msgs[0].buf = (__u8 *)&command;
+ msgs[1].addr = client->addr;
+ msgs[1].flags = I2C_M_RD;
+ msgs[1].len = sizeof(*data);
+ msgs[1].buf = (__u8 *)data;
+
+ ret = i2c_transfer(client->adapter, msgs, 2);
+ if (ret == 2)
+ return 0;
+
+ trace_i2cr_i2c_error(ret);
+
+ if (ret < 0)
+ return ret;
+
+ return -EIO;
+}
+
+static int i2cr_check_status(struct i2c_client *client)
+{
+ __be64 status_be = 0;
+ u64 status;
+ int ret;
+
+ ret = i2cr_transfer(client, I2CR_STATUS, &status_be);
+ if (ret)
+ return ret;
+
+ status = be64_to_cpu(status_be);
+ if (status & I2CR_STATUS_ERR) {
+ __be64 error_be = 0;
+ u64 error;
+
+ i2cr_transfer(client, I2CR_ERROR, &error_be);
+ error = be64_to_cpu(error_be);
+ trace_i2cr_status_error(status, error);
+ dev_err(&client->dev, "status:%016llx error:%016llx\n", status, error);
+ return -EREMOTEIO;
+ }
+
+ trace_i2cr_status(status);
+ return 0;
+}
+
+static int i2cr_read(struct fsi_master *master, int link, uint8_t id, uint32_t addr, void *val,
+ size_t size)
+{
+ struct fsi_master_i2cr *i2cr = container_of(master, struct fsi_master_i2cr, master);
+ __be64 data = 0;
+ int ret;
+
+ if (link || id || (addr & 0xffff0000) || !size || size > 4 || size == 3)
+ return -EINVAL;
+
+ mutex_lock(&i2cr->lock);
+
+ ret = i2cr_transfer(i2cr->client, I2CR_ADDRESS_CFAM(addr), &data);
+ if (ret)
+ goto unlock;
+
+ ret = i2cr_check_status(i2cr->client);
+ if (ret)
+ goto unlock;
+
+ trace_i2cr_read(addr, size, (__force uint32_t)data);
+ memcpy(val, &data, size);
+
+unlock:
+ mutex_unlock(&i2cr->lock);
+ return ret;
+}
+
+static int i2cr_write(struct fsi_master *master, int link, uint8_t id, uint32_t addr,
+ const void *val, size_t size)
+{
+ struct fsi_master_i2cr *i2cr = container_of(master, struct fsi_master_i2cr, master);
+ __be32 data[3];
+ int ret;
+
+ if (link || id || (addr & 0xffff0000) || !size || size > 4 || size == 3)
+ return -EINVAL;
+
+ data[1] = 0;
+ memcpy(&data[1], val, size);
+ data[0] = i2cr_get_command(I2CR_ADDRESS_CFAM(addr),
+ i2cr_check_parity((__force u32)data[1], true));
+ data[2] = 0;
+
+ mutex_lock(&i2cr->lock);
+
+ ret = i2c_master_send(i2cr->client, (const char *)data, sizeof(data));
+ if (ret == sizeof(data)) {
+ ret = i2cr_check_status(i2cr->client);
+ if (!ret)
+ trace_i2cr_write(addr, size, (__force uint32_t)data[1]);
+ } else {
+ trace_i2cr_i2c_error(ret);
+
+ if (ret >= 0)
+ ret = -EIO;
+ }
+
+ mutex_unlock(&i2cr->lock);
+ return ret;
+}
+
+static int i2cr_probe(struct i2c_client *client)
+{
+ struct fsi_master_i2cr *i2cr;
+ int ret;
+
+ i2cr = devm_kzalloc(&client->dev, sizeof(*i2cr), GFP_KERNEL);
+ if (!i2cr)
+ return -ENOMEM;
+
+ i2cr->master.dev.parent = &client->dev;
+ i2cr->master.dev.of_node = of_node_get(dev_of_node(&client->dev));
+
+ i2cr->master.n_links = 1;
+ i2cr->master.read = i2cr_read;
+ i2cr->master.write = i2cr_write;
+
+ mutex_init(&i2cr->lock);
+ i2cr->client = client;
+
+ ret = fsi_master_register(&i2cr->master);
+ if (ret)
+ return ret;
+
+ i2c_set_clientdata(client, i2cr);
+ return 0;
+}
+
+static int i2cr_remove(struct i2c_client *client)
+{
+ struct fsi_master_i2cr *i2cr = i2c_get_clientdata(client);
+
+ fsi_master_unregister(&i2cr->master);
+
+ return 0;
+}
+
+static const struct of_device_id i2cr_i2c_ids[] = {
+ { .compatible = "ibm,i2cr", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, i2cr_i2c_ids);
+
+static struct i2c_driver i2cr_driver = {
+ .probe_new = i2cr_probe,
+ .remove = i2cr_remove,
+ .driver = {
+ .name = "i2cr",
+ .of_match_table = i2cr_i2c_ids,
+ },
+};
+
+module_i2c_driver(i2cr_driver)
+
+MODULE_AUTHOR("Eddie James <eajames@...ux.ibm.com>");
+MODULE_DESCRIPTION("IBM I2C Responder virtual FSI master driver");
+MODULE_LICENSE("GPL");
diff --git a/include/trace/events/fsi_master_i2cr.h b/include/trace/events/fsi_master_i2cr.h
new file mode 100644
index 000000000000..7b53c6a35bc7
--- /dev/null
+++ b/include/trace/events/fsi_master_i2cr.h
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM fsi_master_i2cr
+
+#if !defined(_TRACE_FSI_MASTER_I2CR_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_FSI_MASTER_I2CR_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(i2cr_command,
+ TP_PROTO(uint32_t command),
+ TP_ARGS(command),
+ TP_STRUCT__entry(
+ __field(uint32_t, command)
+ ),
+ TP_fast_assign(
+ __entry->command = command;
+ ),
+ TP_printk("command:%08x", __entry->command)
+);
+
+TRACE_EVENT(i2cr_i2c_error,
+ TP_PROTO(int rc),
+ TP_ARGS(rc),
+ TP_STRUCT__entry(
+ __field(int, rc)
+ ),
+ TP_fast_assign(
+ __entry->rc = rc;
+ ),
+ TP_printk("rc:%d", __entry->rc)
+);
+
+TRACE_EVENT(i2cr_read,
+ TP_PROTO(uint32_t addr, size_t size, uint64_t result),
+ TP_ARGS(addr, size, result),
+ TP_STRUCT__entry(
+ __field(uint32_t, addr)
+ __field(size_t, size)
+ __field(uint64_t, result)
+ ),
+ TP_fast_assign(
+ __entry->addr = addr;
+ __entry->size = size;
+ __entry->result = result;
+ ),
+ TP_printk("addr:%08x size:%zu result:%016llx", __entry->addr, __entry->size,
+ __entry->result)
+);
+
+TRACE_EVENT(i2cr_status,
+ TP_PROTO(uint64_t status),
+ TP_ARGS(status),
+ TP_STRUCT__entry(
+ __field(uint32_t, status)
+ ),
+ TP_fast_assign(
+ __entry->status = status >> 32;
+ ),
+ TP_printk("status:%08x", __entry->status)
+);
+
+TRACE_EVENT(i2cr_status_error,
+ TP_PROTO(uint64_t status, uint64_t error),
+ TP_ARGS(status, error),
+ TP_STRUCT__entry(
+ __field(uint64_t, error)
+ __field(uint32_t, status)
+ ),
+ TP_fast_assign(
+ __entry->error = error;
+ __entry->status = status >> 32;
+ ),
+ TP_printk("status:%08x error:%016llx", __entry->status, __entry->error)
+);
+
+TRACE_EVENT(i2cr_write,
+ TP_PROTO(uint32_t addr, uint32_t val, size_t size),
+ TP_ARGS(addr, val, size),
+ TP_STRUCT__entry(
+ __field(uint32_t, addr)
+ __field(uint32_t, val)
+ __field(size_t, size)
+ ),
+ TP_fast_assign(
+ __entry->addr = addr;
+ __entry->val = val;
+ __entry->size = size;
+ ),
+ TP_printk("addr:%08x val:%08x size:%zu", __entry->addr, __entry->val, __entry->size)
+);
+
+#endif
+
+#include <trace/define_trace.h>
--
2.31.1
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