--- /dev/null
+// 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");
projects / thirdparty / kernel / linux.git / commitdiff
