Kernel/linux
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2024-12-28 16:53:49 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity
master
linux/drivers/mfd/cgbc-core.c
Christophe JAILLET 5a700e77d6 mfd: cgbc-core: Fix error handling paths in cgbc_init_device() 
If an error occurs after a cgbc_session_request() call, it should be
balanced by a corresponding cgbc_session_release(), as already done in the
remove function.

Fixes: 6f1067cfbe ("mfd: Add Congatec Board Controller driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Thomas Richard <thomas.richard@bootlin.com>
Link: https://lore.kernel.org/r/83194335554146efc52c331993f083bd765db6f9.1730205085.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Lee Jones <lee@kernel.org>
2024-11-05 16:13:47 +00:00

421 lines
9.9 KiB
C
Raw Permalink Blame History

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Congatec Board Controller core driver.
*
* The x86 Congatec modules have an embedded micro controller named Board
* Controller. This Board Controller has a Watchdog timer, some GPIOs, and two
* I2C busses.
*
* Copyright (C) 2024 Bootlin
*
* Author: Thomas Richard <thomas.richard@bootlin.com>
*/
#include <linux/dmi.h>
#include <linux/iopoll.h>
#include <linux/mfd/cgbc.h>
#include <linux/mfd/core.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/sysfs.h>
#define CGBC_IO_SESSION_BASE 0x0E20
#define CGBC_IO_SESSION_END 0x0E30
#define CGBC_IO_CMD_BASE 0x0E00
#define CGBC_IO_CMD_END 0x0E10
#define CGBC_MASK_STATUS (BIT(6) | BIT(7))
#define CGBC_MASK_DATA_COUNT 0x1F
#define CGBC_MASK_ERROR_CODE 0x1F
#define CGBC_STATUS_DATA_READY 0x00
#define CGBC_STATUS_CMD_READY BIT(6)
#define CGBC_STATUS_ERROR (BIT(6) | BIT(7))
#define CGBC_SESSION_CMD 0x00
#define CGBC_SESSION_CMD_IDLE 0x00
#define CGBC_SESSION_CMD_REQUEST 0x01
#define CGBC_SESSION_DATA 0x01
#define CGBC_SESSION_STATUS 0x02
#define CGBC_SESSION_STATUS_FREE 0x03
#define CGBC_SESSION_ACCESS 0x04
#define CGBC_SESSION_ACCESS_GAINED 0x00
#define CGBC_SESSION_VALID_MIN 0x02
#define CGBC_SESSION_VALID_MAX 0xFE
#define CGBC_CMD_STROBE 0x00
#define CGBC_CMD_INDEX 0x02
#define CGBC_CMD_INDEX_CBM_MAN8 0x00
#define CGBC_CMD_INDEX_CBM_AUTO32 0x03
#define CGBC_CMD_DATA 0x04
#define CGBC_CMD_ACCESS 0x0C
#define CGBC_CMD_GET_FW_REV 0x21
static struct platform_device *cgbc_pdev;
/* Wait the Board Controller is ready to receive some session commands */
static int cgbc_wait_device(struct cgbc_device_data *cgbc)
{
u16 status;
int ret;
ret = readx_poll_timeout(ioread16, cgbc->io_session + CGBC_SESSION_STATUS, status,
status == CGBC_SESSION_STATUS_FREE, 0, 500000);
if (ret || ioread32(cgbc->io_session + CGBC_SESSION_ACCESS))
ret = -ENODEV;
return ret;
}
static int cgbc_session_command(struct cgbc_device_data *cgbc, u8 cmd)
{
int ret;
u8 val;
ret = readx_poll_timeout(ioread8, cgbc->io_session + CGBC_SESSION_CMD, val,
val == CGBC_SESSION_CMD_IDLE, 0, 100000);
if (ret)
return ret;
iowrite8(cmd, cgbc->io_session + CGBC_SESSION_CMD);
ret = readx_poll_timeout(ioread8, cgbc->io_session + CGBC_SESSION_CMD, val,
val == CGBC_SESSION_CMD_IDLE, 0, 100000);
if (ret)
return ret;
ret = (int)ioread8(cgbc->io_session + CGBC_SESSION_DATA);
iowrite8(CGBC_SESSION_STATUS_FREE, cgbc->io_session + CGBC_SESSION_STATUS);
return ret;
}
static int cgbc_session_request(struct cgbc_device_data *cgbc)
{
unsigned int ret;
ret = cgbc_wait_device(cgbc);
if (ret)
return dev_err_probe(cgbc->dev, ret, "device not found or not ready\n");
cgbc->session = cgbc_session_command(cgbc, CGBC_SESSION_CMD_REQUEST);
/* The Board Controller sent us a wrong session handle, we cannot communicate with it */
if (cgbc->session < CGBC_SESSION_VALID_MIN || cgbc->session > CGBC_SESSION_VALID_MAX)
return dev_err_probe(cgbc->dev, -ECONNREFUSED,
"failed to get a valid session handle\n");
return 0;
}
static void cgbc_session_release(struct cgbc_device_data *cgbc)
{
if (cgbc_session_command(cgbc, cgbc->session) != cgbc->session)
dev_warn(cgbc->dev, "failed to release session\n");
}
static bool cgbc_command_lock(struct cgbc_device_data *cgbc)
{
iowrite8(cgbc->session, cgbc->io_cmd + CGBC_CMD_ACCESS);
return ioread8(cgbc->io_cmd + CGBC_CMD_ACCESS) == cgbc->session;
}
static void cgbc_command_unlock(struct cgbc_device_data *cgbc)
{
iowrite8(cgbc->session, cgbc->io_cmd + CGBC_CMD_ACCESS);
}
int cgbc_command(struct cgbc_device_data *cgbc, void *cmd, unsigned int cmd_size, void *data,
unsigned int data_size, u8 *status)
{
u8 checksum = 0, data_checksum = 0, istatus = 0, val;
u8 *_data = (u8 *)data;
u8 *_cmd = (u8 *)cmd;
int mode_change = -1;
bool lock;
int ret, i;
mutex_lock(&cgbc->lock);
/* Request access */
ret = readx_poll_timeout(cgbc_command_lock, cgbc, lock, lock, 0, 100000);
if (ret)
goto out;
/* Wait board controller is ready */
ret = readx_poll_timeout(ioread8, cgbc->io_cmd + CGBC_CMD_STROBE, val,
val == CGBC_CMD_STROBE, 0, 100000);
if (ret)
goto release;
/* Write command packet */
if (cmd_size <= 2) {
iowrite8(CGBC_CMD_INDEX_CBM_MAN8, cgbc->io_cmd + CGBC_CMD_INDEX);
} else {
iowrite8(CGBC_CMD_INDEX_CBM_AUTO32, cgbc->io_cmd + CGBC_CMD_INDEX);
if ((cmd_size % 4) != 0x03)
mode_change = (cmd_size & 0xFFFC) - 1;
}
for (i = 0; i < cmd_size; i++) {
iowrite8(_cmd[i], cgbc->io_cmd + CGBC_CMD_DATA + (i % 4));
checksum ^= _cmd[i];
if (mode_change == i)
iowrite8((i + 1) | CGBC_CMD_INDEX_CBM_MAN8, cgbc->io_cmd + CGBC_CMD_INDEX);
}
/* Append checksum byte */
iowrite8(checksum, cgbc->io_cmd + CGBC_CMD_DATA + (i % 4));
/* Perform command strobe */
iowrite8(cgbc->session, cgbc->io_cmd + CGBC_CMD_STROBE);
/* Rewind cmd buffer index */
iowrite8(CGBC_CMD_INDEX_CBM_AUTO32, cgbc->io_cmd + CGBC_CMD_INDEX);
/* Wait command completion */
ret = read_poll_timeout(ioread8, val, val == CGBC_CMD_STROBE, 0, 100000, false,
cgbc->io_cmd + CGBC_CMD_STROBE);
if (ret)
goto release;
istatus = ioread8(cgbc->io_cmd + CGBC_CMD_DATA);
checksum = istatus;
/* Check command status */
switch (istatus & CGBC_MASK_STATUS) {
case CGBC_STATUS_DATA_READY:
if (istatus > data_size)
istatus = data_size;
for (i = 0; i < istatus; i++) {
_data[i] = ioread8(cgbc->io_cmd + CGBC_CMD_DATA + ((i + 1) % 4));
checksum ^= _data[i];
}
data_checksum = ioread8(cgbc->io_cmd + CGBC_CMD_DATA + ((i + 1) % 4));
istatus &= CGBC_MASK_DATA_COUNT;
break;
case CGBC_STATUS_ERROR:
case CGBC_STATUS_CMD_READY:
data_checksum = ioread8(cgbc->io_cmd + CGBC_CMD_DATA + 1);
if ((istatus & CGBC_MASK_STATUS) == CGBC_STATUS_ERROR)
ret = -EIO;
istatus = istatus & CGBC_MASK_ERROR_CODE;
break;
default:
data_checksum = ioread8(cgbc->io_cmd + CGBC_CMD_DATA + 1);
istatus &= CGBC_MASK_ERROR_CODE;
ret = -EIO;
break;
}
/* Checksum verification */
if (ret == 0 && data_checksum != checksum)
ret = -EIO;
release:
cgbc_command_unlock(cgbc);
out:
mutex_unlock(&cgbc->lock);
if (status)
*status = istatus;
return ret;
}
EXPORT_SYMBOL_GPL(cgbc_command);
static struct mfd_cell cgbc_devs[] = {
{ .name = "cgbc-wdt" },
{ .name = "cgbc-gpio" },
{ .name = "cgbc-i2c", .id = 1 },
{ .name = "cgbc-i2c", .id = 2 },
};
static int cgbc_map(struct cgbc_device_data *cgbc)
{
struct device *dev = cgbc->dev;
struct platform_device *pdev = to_platform_device(dev);
struct resource *ioport;
ioport = platform_get_resource(pdev, IORESOURCE_IO, 0);
if (!ioport)
return -EINVAL;
cgbc->io_session = devm_ioport_map(dev, ioport->start, resource_size(ioport));
if (!cgbc->io_session)
return -ENOMEM;
ioport = platform_get_resource(pdev, IORESOURCE_IO, 1);
if (!ioport)
return -EINVAL;
cgbc->io_cmd = devm_ioport_map(dev, ioport->start, resource_size(ioport));
if (!cgbc->io_cmd)
return -ENOMEM;
return 0;
}
static const struct resource cgbc_resources[] = {
{
.start = CGBC_IO_SESSION_BASE,
.end = CGBC_IO_SESSION_END,
.flags = IORESOURCE_IO,
},
{
.start = CGBC_IO_CMD_BASE,
.end = CGBC_IO_CMD_END,
.flags = IORESOURCE_IO,
},
};
static ssize_t cgbc_version_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cgbc_device_data *cgbc = dev_get_drvdata(dev);
return sysfs_emit(buf, "CGBCP%c%c%c\n", cgbc->version.feature, cgbc->version.major,
cgbc->version.minor);
}
static DEVICE_ATTR_RO(cgbc_version);
static struct attribute *cgbc_attrs[] = {
&dev_attr_cgbc_version.attr,
NULL
};
ATTRIBUTE_GROUPS(cgbc);
static int cgbc_get_version(struct cgbc_device_data *cgbc)
{
u8 cmd = CGBC_CMD_GET_FW_REV;
u8 data[4];
int ret;
ret = cgbc_command(cgbc, &cmd, 1, &data, sizeof(data), NULL);
if (ret)
return ret;
cgbc->version.feature = data[0];
cgbc->version.major = data[1];
cgbc->version.minor = data[2];
return 0;
}
static int cgbc_init_device(struct cgbc_device_data *cgbc)
{
int ret;
ret = cgbc_session_request(cgbc);
if (ret)
return ret;
ret = cgbc_get_version(cgbc);
if (ret)
goto release_session;
ret = mfd_add_devices(cgbc->dev, -1, cgbc_devs, ARRAY_SIZE(cgbc_devs),
NULL, 0, NULL);
if (ret)
goto release_session;
return 0;
release_session:
cgbc_session_release(cgbc);
return ret;
}
static int cgbc_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct cgbc_device_data *cgbc;
int ret;
cgbc = devm_kzalloc(dev, sizeof(*cgbc), GFP_KERNEL);
if (!cgbc)
return -ENOMEM;
cgbc->dev = dev;
ret = cgbc_map(cgbc);
if (ret)
return ret;
mutex_init(&cgbc->lock);
platform_set_drvdata(pdev, cgbc);
return cgbc_init_device(cgbc);
}
static void cgbc_remove(struct platform_device *pdev)
{
struct cgbc_device_data *cgbc = platform_get_drvdata(pdev);
cgbc_session_release(cgbc);
mfd_remove_devices(&pdev->dev);
}
static struct platform_driver cgbc_driver = {
.driver = {
.name = "cgbc",
.dev_groups = cgbc_groups,
},
.probe = cgbc_probe,
.remove = cgbc_remove,
};
static const struct dmi_system_id cgbc_dmi_table[] __initconst = {
{
.ident = "SA7",
.matches = {
DMI_MATCH(DMI_BOARD_VENDOR, "congatec"),
DMI_MATCH(DMI_BOARD_NAME, "conga-SA7"),
},
},
{}
};
MODULE_DEVICE_TABLE(dmi, cgbc_dmi_table);
static int __init cgbc_init(void)
{
const struct dmi_system_id *id;
int ret = -ENODEV;
id = dmi_first_match(cgbc_dmi_table);
if (IS_ERR_OR_NULL(id))
return ret;
cgbc_pdev = platform_device_register_simple("cgbc", PLATFORM_DEVID_NONE, cgbc_resources,
ARRAY_SIZE(cgbc_resources));
if (IS_ERR(cgbc_pdev))
return PTR_ERR(cgbc_pdev);
return platform_driver_register(&cgbc_driver);
}
static void __exit cgbc_exit(void)
{
platform_device_unregister(cgbc_pdev);
platform_driver_unregister(&cgbc_driver);
}
module_init(cgbc_init);
module_exit(cgbc_exit);
MODULE_DESCRIPTION("Congatec Board Controller Core Driver");
MODULE_AUTHOR("Thomas Richard <thomas.richard@bootlin.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:cgbc-core");
Reference in New Issue View Git Blame Copy Permalink