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linux/drivers/i2c/busses/i2c-scmi.c
Edgar Cherkasov e058e7a4bc i2c: i2c-scmi: add a MS HID 
Description of the problem:
 - i2c-scmi driver contains only two identifiers "SMBUS01" and "SMBUSIBM";
 - the fist HID (SMBUS01) is clearly defined in "SMBus Control Method
   Interface Specification, version 1.0": "Each device must specify
   'SMBUS01' as its _HID and use a unique _UID value";
 - unfortunately, BIOS vendors (like AMI) seem to ignore this requirement
   and implement "SMB0001" HID instead of "SMBUS01";
 - I speculate that they do this because only "SMB0001" is hard coded in
   Windows SMBus driver produced by Microsoft.

This leads to following situation:
 - SMBus works out of box in Windows but not in Linux;
 - board vendors are forced to add correct "SMBUS01" HID to BIOS to make
   SMBus work in Linux. Moreover the same board vendors complain that
   tools (3-rd party ASL compiler) do not like the "SMBUS01" identifier
   and produce errors.  So they need to constantly patch the compiler for
   each new version of BIOS.

As it is very unlikely that BIOS vendors implement a correct HID in
future, I would propose to consider whether it is possible to work around
the problem by adding MS HID to the Linux i2c-scmi driver.

v2: move the definition of the new HID to the driver itself.

Signed-off-by: Edgar Cherkasov <echerkasov@dev.rtsoft.ru>
Signed-off-by: Michael Brunner <Michael.Brunner@kontron.com>
Acked-by: Viktor Krasnov <vkrasnov@dev.rtsoft.ru>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-04-16 21:48:06 +02:00

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/*
* SMBus driver for ACPI SMBus CMI
*
* Copyright (C) 2009 Crane Cai <crane.cai@amd.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation version 2.
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/i2c.h>
#include <linux/acpi.h>
#define ACPI_SMBUS_HC_CLASS "smbus"
#define ACPI_SMBUS_HC_DEVICE_NAME "cmi"
/* SMBUS HID definition as supported by Microsoft Windows */
#define ACPI_SMBUS_MS_HID "SMB0001"
ACPI_MODULE_NAME("smbus_cmi");
struct smbus_methods_t {
char *mt_info;
char *mt_sbr;
char *mt_sbw;
};
struct acpi_smbus_cmi {
acpi_handle handle;
struct i2c_adapter adapter;
u8 cap_info:1;
u8 cap_read:1;
u8 cap_write:1;
struct smbus_methods_t *methods;
};
static const struct smbus_methods_t smbus_methods = {
.mt_info = "_SBI",
.mt_sbr = "_SBR",
.mt_sbw = "_SBW",
};
/* Some IBM BIOSes omit the leading underscore */
static const struct smbus_methods_t ibm_smbus_methods = {
.mt_info = "SBI_",
.mt_sbr = "SBR_",
.mt_sbw = "SBW_",
};
static const struct acpi_device_id acpi_smbus_cmi_ids[] = {
{"SMBUS01", (kernel_ulong_t)&smbus_methods},
{ACPI_SMBUS_IBM_HID, (kernel_ulong_t)&ibm_smbus_methods},
{ACPI_SMBUS_MS_HID, (kernel_ulong_t)&smbus_methods},
{"", 0}
};
MODULE_DEVICE_TABLE(acpi, acpi_smbus_cmi_ids);
#define ACPI_SMBUS_STATUS_OK 0x00
#define ACPI_SMBUS_STATUS_FAIL 0x07
#define ACPI_SMBUS_STATUS_DNAK 0x10
#define ACPI_SMBUS_STATUS_DERR 0x11
#define ACPI_SMBUS_STATUS_CMD_DENY 0x12
#define ACPI_SMBUS_STATUS_UNKNOWN 0x13
#define ACPI_SMBUS_STATUS_ACC_DENY 0x17
#define ACPI_SMBUS_STATUS_TIMEOUT 0x18
#define ACPI_SMBUS_STATUS_NOTSUP 0x19
#define ACPI_SMBUS_STATUS_BUSY 0x1a
#define ACPI_SMBUS_STATUS_PEC 0x1f
#define ACPI_SMBUS_PRTCL_WRITE 0x00
#define ACPI_SMBUS_PRTCL_READ 0x01
#define ACPI_SMBUS_PRTCL_QUICK 0x02
#define ACPI_SMBUS_PRTCL_BYTE 0x04
#define ACPI_SMBUS_PRTCL_BYTE_DATA 0x06
#define ACPI_SMBUS_PRTCL_WORD_DATA 0x08
#define ACPI_SMBUS_PRTCL_BLOCK_DATA 0x0a
static int
acpi_smbus_cmi_access(struct i2c_adapter *adap, u16 addr, unsigned short flags,
char read_write, u8 command, int size,
union i2c_smbus_data *data)
{
int result = 0;
struct acpi_smbus_cmi *smbus_cmi = adap->algo_data;
unsigned char protocol;
acpi_status status = 0;
struct acpi_object_list input;
union acpi_object mt_params[5];
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *obj;
union acpi_object *pkg;
char *method;
int len = 0;
dev_dbg(&adap->dev, "access size: %d %s\n", size,
(read_write) ? "READ" : "WRITE");
switch (size) {
case I2C_SMBUS_QUICK:
protocol = ACPI_SMBUS_PRTCL_QUICK;
command = 0;
if (read_write == I2C_SMBUS_WRITE) {
mt_params[3].type = ACPI_TYPE_INTEGER;
mt_params[3].integer.value = 0;
mt_params[4].type = ACPI_TYPE_INTEGER;
mt_params[4].integer.value = 0;
}
break;
case I2C_SMBUS_BYTE:
protocol = ACPI_SMBUS_PRTCL_BYTE;
if (read_write == I2C_SMBUS_WRITE) {
mt_params[3].type = ACPI_TYPE_INTEGER;
mt_params[3].integer.value = 0;
mt_params[4].type = ACPI_TYPE_INTEGER;
mt_params[4].integer.value = 0;
} else {
command = 0;
}
break;
case I2C_SMBUS_BYTE_DATA:
protocol = ACPI_SMBUS_PRTCL_BYTE_DATA;
if (read_write == I2C_SMBUS_WRITE) {
mt_params[3].type = ACPI_TYPE_INTEGER;
mt_params[3].integer.value = 1;
mt_params[4].type = ACPI_TYPE_INTEGER;
mt_params[4].integer.value = data->byte;
}
break;
case I2C_SMBUS_WORD_DATA:
protocol = ACPI_SMBUS_PRTCL_WORD_DATA;
if (read_write == I2C_SMBUS_WRITE) {
mt_params[3].type = ACPI_TYPE_INTEGER;
mt_params[3].integer.value = 2;
mt_params[4].type = ACPI_TYPE_INTEGER;
mt_params[4].integer.value = data->word;
}
break;
case I2C_SMBUS_BLOCK_DATA:
protocol = ACPI_SMBUS_PRTCL_BLOCK_DATA;
if (read_write == I2C_SMBUS_WRITE) {
len = data->block[0];
if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
return -EINVAL;
mt_params[3].type = ACPI_TYPE_INTEGER;
mt_params[3].integer.value = len;
mt_params[4].type = ACPI_TYPE_BUFFER;
mt_params[4].buffer.pointer = data->block + 1;
}
break;
default:
dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
return -EOPNOTSUPP;
}
if (read_write == I2C_SMBUS_READ) {
protocol |= ACPI_SMBUS_PRTCL_READ;
method = smbus_cmi->methods->mt_sbr;
input.count = 3;
} else {
protocol |= ACPI_SMBUS_PRTCL_WRITE;
method = smbus_cmi->methods->mt_sbw;
input.count = 5;
}
input.pointer = mt_params;
mt_params[0].type = ACPI_TYPE_INTEGER;
mt_params[0].integer.value = protocol;
mt_params[1].type = ACPI_TYPE_INTEGER;
mt_params[1].integer.value = addr;
mt_params[2].type = ACPI_TYPE_INTEGER;
mt_params[2].integer.value = command;
status = acpi_evaluate_object(smbus_cmi->handle, method, &input,
&buffer);
if (ACPI_FAILURE(status)) {
ACPI_ERROR((AE_INFO, "Evaluating %s: %i", method, status));
return -EIO;
}
pkg = buffer.pointer;
if (pkg && pkg->type == ACPI_TYPE_PACKAGE)
obj = pkg->package.elements;
else {
ACPI_ERROR((AE_INFO, "Invalid argument type"));
result = -EIO;
goto out;
}
if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
ACPI_ERROR((AE_INFO, "Invalid argument type"));
result = -EIO;
goto out;
}
result = obj->integer.value;
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "%s return status: %i\n",
method, result));
switch (result) {
case ACPI_SMBUS_STATUS_OK:
result = 0;
break;
case ACPI_SMBUS_STATUS_BUSY:
result = -EBUSY;
goto out;
case ACPI_SMBUS_STATUS_TIMEOUT:
result = -ETIMEDOUT;
goto out;
case ACPI_SMBUS_STATUS_DNAK:
result = -ENXIO;
goto out;
default:
result = -EIO;
goto out;
}
if (read_write == I2C_SMBUS_WRITE || size == I2C_SMBUS_QUICK)
goto out;
obj = pkg->package.elements + 1;
if (obj->type != ACPI_TYPE_INTEGER) {
ACPI_ERROR((AE_INFO, "Invalid argument type"));
result = -EIO;
goto out;
}
len = obj->integer.value;
obj = pkg->package.elements + 2;
switch (size) {
case I2C_SMBUS_BYTE:
case I2C_SMBUS_BYTE_DATA:
case I2C_SMBUS_WORD_DATA:
if (obj->type != ACPI_TYPE_INTEGER) {
ACPI_ERROR((AE_INFO, "Invalid argument type"));
result = -EIO;
goto out;
}
if (len == 2)
data->word = obj->integer.value;
else
data->byte = obj->integer.value;
break;
case I2C_SMBUS_BLOCK_DATA:
if (obj->type != ACPI_TYPE_BUFFER) {
ACPI_ERROR((AE_INFO, "Invalid argument type"));
result = -EIO;
goto out;
}
if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
return -EPROTO;
data->block[0] = len;
memcpy(data->block + 1, obj->buffer.pointer, len);
break;
}
out:
kfree(buffer.pointer);
dev_dbg(&adap->dev, "Transaction status: %i\n", result);
return result;
}
static u32 acpi_smbus_cmi_func(struct i2c_adapter *adapter)
{
struct acpi_smbus_cmi *smbus_cmi = adapter->algo_data;
u32 ret;
ret = smbus_cmi->cap_read | smbus_cmi->cap_write ?
I2C_FUNC_SMBUS_QUICK : 0;
ret |= smbus_cmi->cap_read ?
(I2C_FUNC_SMBUS_READ_BYTE |
I2C_FUNC_SMBUS_READ_BYTE_DATA |
I2C_FUNC_SMBUS_READ_WORD_DATA |
I2C_FUNC_SMBUS_READ_BLOCK_DATA) : 0;
ret |= smbus_cmi->cap_write ?
(I2C_FUNC_SMBUS_WRITE_BYTE |
I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
I2C_FUNC_SMBUS_WRITE_WORD_DATA |
I2C_FUNC_SMBUS_WRITE_BLOCK_DATA) : 0;
return ret;
}
static const struct i2c_algorithm acpi_smbus_cmi_algorithm = {
.smbus_xfer = acpi_smbus_cmi_access,
.functionality = acpi_smbus_cmi_func,
};
static int acpi_smbus_cmi_add_cap(struct acpi_smbus_cmi *smbus_cmi,
const char *name)
{
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *obj;
acpi_status status;
if (!strcmp(name, smbus_cmi->methods->mt_info)) {
status = acpi_evaluate_object(smbus_cmi->handle,
smbus_cmi->methods->mt_info,
NULL, &buffer);
if (ACPI_FAILURE(status)) {
ACPI_ERROR((AE_INFO, "Evaluating %s: %i",
smbus_cmi->methods->mt_info, status));
return -EIO;
}
obj = buffer.pointer;
if (obj && obj->type == ACPI_TYPE_PACKAGE)
obj = obj->package.elements;
else {
ACPI_ERROR((AE_INFO, "Invalid argument type"));
kfree(buffer.pointer);
return -EIO;
}
if (obj->type != ACPI_TYPE_INTEGER) {
ACPI_ERROR((AE_INFO, "Invalid argument type"));
kfree(buffer.pointer);
return -EIO;
} else
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "SMBus CMI Version %x"
"\n", (int)obj->integer.value));
kfree(buffer.pointer);
smbus_cmi->cap_info = 1;
} else if (!strcmp(name, smbus_cmi->methods->mt_sbr))
smbus_cmi->cap_read = 1;
else if (!strcmp(name, smbus_cmi->methods->mt_sbw))
smbus_cmi->cap_write = 1;
else
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Unsupported CMI method: %s\n",
name));
return 0;
}
static acpi_status acpi_smbus_cmi_query_methods(acpi_handle handle, u32 level,
void *context, void **return_value)
{
char node_name[5];
struct acpi_buffer buffer = { sizeof(node_name), node_name };
struct acpi_smbus_cmi *smbus_cmi = context;
acpi_status status;
status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
if (ACPI_SUCCESS(status))
acpi_smbus_cmi_add_cap(smbus_cmi, node_name);
return AE_OK;
}
static int acpi_smbus_cmi_add(struct acpi_device *device)
{
struct acpi_smbus_cmi *smbus_cmi;
const struct acpi_device_id *id;
smbus_cmi = kzalloc(sizeof(struct acpi_smbus_cmi), GFP_KERNEL);
if (!smbus_cmi)
return -ENOMEM;
smbus_cmi->handle = device->handle;
strcpy(acpi_device_name(device), ACPI_SMBUS_HC_DEVICE_NAME);
strcpy(acpi_device_class(device), ACPI_SMBUS_HC_CLASS);
device->driver_data = smbus_cmi;
smbus_cmi->cap_info = 0;
smbus_cmi->cap_read = 0;
smbus_cmi->cap_write = 0;
for (id = acpi_smbus_cmi_ids; id->id[0]; id++)
if (!strcmp(id->id, acpi_device_hid(device)))
smbus_cmi->methods =
(struct smbus_methods_t *) id->driver_data;
acpi_walk_namespace(ACPI_TYPE_METHOD, smbus_cmi->handle, 1,
acpi_smbus_cmi_query_methods, NULL, smbus_cmi, NULL);
if (smbus_cmi->cap_info == 0)
goto err;
snprintf(smbus_cmi->adapter.name, sizeof(smbus_cmi->adapter.name),
"SMBus CMI adapter %s",
acpi_device_name(device));
smbus_cmi->adapter.owner = THIS_MODULE;
smbus_cmi->adapter.algo = &acpi_smbus_cmi_algorithm;
smbus_cmi->adapter.algo_data = smbus_cmi;
smbus_cmi->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
smbus_cmi->adapter.dev.parent = &device->dev;
if (i2c_add_adapter(&smbus_cmi->adapter)) {
dev_err(&device->dev, "Couldn't register adapter!\n");
goto err;
}
return 0;
err:
kfree(smbus_cmi);
device->driver_data = NULL;
return -EIO;
}
static int acpi_smbus_cmi_remove(struct acpi_device *device)
{
struct acpi_smbus_cmi *smbus_cmi = acpi_driver_data(device);
i2c_del_adapter(&smbus_cmi->adapter);
kfree(smbus_cmi);
device->driver_data = NULL;
return 0;
}
static struct acpi_driver acpi_smbus_cmi_driver = {
.name = ACPI_SMBUS_HC_DEVICE_NAME,
.class = ACPI_SMBUS_HC_CLASS,
.ids = acpi_smbus_cmi_ids,
.ops = {
.add = acpi_smbus_cmi_add,
.remove = acpi_smbus_cmi_remove,
},
};
module_acpi_driver(acpi_smbus_cmi_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Crane Cai <crane.cai@amd.com>");
MODULE_DESCRIPTION("ACPI SMBus CMI driver");
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