diff options
Diffstat (limited to 'drivers/mfd/cgbc-core.c')
| -rw-r--r-- | drivers/mfd/cgbc-core.c | 411 |
1 files changed, 411 insertions, 0 deletions
diff --git a/drivers/mfd/cgbc-core.c b/drivers/mfd/cgbc-core.c new file mode 100644 index 000000000000..93004a6b29c1 --- /dev/null +++ b/drivers/mfd/cgbc-core.c @@ -0,0 +1,411 @@ +// 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) + return ret; + + return mfd_add_devices(cgbc->dev, -1, cgbc_devs, ARRAY_SIZE(cgbc_devs), NULL, 0, NULL); +} + +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_new = 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"); |