platform/x86: intel_pmc_ipc: Convert to MFD

This driver only creates a bunch of platform devices sharing resources
belonging to the PMC device. This is pretty much what MFD subsystem is
for so move the driver there, renaming it to intel_pmc_bxt.c which
should be more clear what it is.

MFD subsystem provides nice helper APIs for subdevice creation so
convert the driver to use those. Unfortunately the ACPI device includes
separate resources for most of the subdevices so we cannot simply call
mfd_add_devices() to create all of them but instead we need to call it
separately for each device.

The new MFD driver continues to expose two sysfs attributes that allow
userspace to send IPC commands to the PMC/SCU to avoid breaking any
existing applications that may use these. Generally this is bad idea so
document this in the ABI documentation.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

1 files changed, 468 insertions, 0 deletions

diff --git a/drivers/mfd/intel_pmc_bxt.c b/drivers/mfd/intel_pmc_bxt.c
new file mode 100644
index 000000000000..9f01d38acc7f
--- /dev/null
+++ b/drivers/mfd/intel_pmc_bxt.c
@@ -0,0 +1,468 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for the Intel Broxton PMC
+ *
+ * (C) Copyright 2014 - 2020 Intel Corporation
+ *
+ * This driver is based on Intel SCU IPC driver (intel_scu_ipc.c) by
+ * Sreedhara DS <sreedhara.ds@intel.com>
+ *
+ * The PMC (Power Management Controller) running on the ARC processor
+ * communicates with another entity running in the IA (Intel Architecture)
+ * core through an IPC (Intel Processor Communications) mechanism which in
+ * turn sends messages between the IA and the PMC.
+ */
+
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/intel_pmc_bxt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/platform_data/itco_wdt.h>
+
+#include <asm/intel_scu_ipc.h>
+
+/* Residency with clock rate at 19.2MHz to usecs */
+#define S0IX_RESIDENCY_IN_USECS(d, s)		\
+({						\
+	u64 result = 10ull * ((d) + (s));	\
+	do_div(result, 192);			\
+	result;					\
+})
+
+/* Resources exported from IFWI */
+#define PLAT_RESOURCE_IPC_INDEX		0
+#define PLAT_RESOURCE_IPC_SIZE		0x1000
+#define PLAT_RESOURCE_GCR_OFFSET	0x1000
+#define PLAT_RESOURCE_GCR_SIZE		0x1000
+#define PLAT_RESOURCE_BIOS_DATA_INDEX	1
+#define PLAT_RESOURCE_BIOS_IFACE_INDEX	2
+#define PLAT_RESOURCE_TELEM_SSRAM_INDEX	3
+#define PLAT_RESOURCE_ISP_DATA_INDEX	4
+#define PLAT_RESOURCE_ISP_IFACE_INDEX	5
+#define PLAT_RESOURCE_GTD_DATA_INDEX	6
+#define PLAT_RESOURCE_GTD_IFACE_INDEX	7
+#define PLAT_RESOURCE_ACPI_IO_INDEX	0
+
+/*
+ * BIOS does not create an ACPI device for each PMC function, but
+ * exports multiple resources from one ACPI device (IPC) for multiple
+ * functions. This driver is responsible for creating a child device and
+ * to export resources for those functions.
+ */
+#define SMI_EN_OFFSET			0x0040
+#define SMI_EN_SIZE			4
+#define TCO_BASE_OFFSET			0x0060
+#define TCO_REGS_SIZE			16
+#define TELEM_SSRAM_SIZE		240
+#define TELEM_PMC_SSRAM_OFFSET		0x1b00
+#define TELEM_PUNIT_SSRAM_OFFSET	0x1a00
+
+/* Commands */
+#define PMC_NORTHPEAK_CTRL		0xed
+
+static inline bool is_gcr_valid(u32 offset)
+{
+	return offset < PLAT_RESOURCE_GCR_SIZE - 8;
+}
+
+/**
+ * intel_pmc_gcr_read64() - Read a 64-bit PMC GCR register
+ * @pmc: PMC device pointer
+ * @offset: offset of GCR register from GCR address base
+ * @data: data pointer for storing the register output
+ *
+ * Reads the 64-bit PMC GCR register at given offset.
+ *
+ * Return: Negative value on error or 0 on success.
+ */
+int intel_pmc_gcr_read64(struct intel_pmc_dev *pmc, u32 offset, u64 *data)
+{
+	if (!is_gcr_valid(offset))
+		return -EINVAL;
+
+	spin_lock(&pmc->gcr_lock);
+	*data = readq(pmc->gcr_mem_base + offset);
+	spin_unlock(&pmc->gcr_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(intel_pmc_gcr_read64);
+
+/**
+ * intel_pmc_gcr_update() - Update PMC GCR register bits
+ * @pmc: PMC device pointer
+ * @offset: offset of GCR register from GCR address base
+ * @mask: bit mask for update operation
+ * @val: update value
+ *
+ * Updates the bits of given GCR register as specified by
+ * @mask and @val.
+ *
+ * Return: Negative value on error or 0 on success.
+ */
+int intel_pmc_gcr_update(struct intel_pmc_dev *pmc, u32 offset, u32 mask, u32 val)
+{
+	u32 new_val;
+
+	if (!is_gcr_valid(offset))
+		return -EINVAL;
+
+	spin_lock(&pmc->gcr_lock);
+	new_val = readl(pmc->gcr_mem_base + offset);
+
+	new_val = (new_val & ~mask) | (val & mask);
+	writel(new_val, pmc->gcr_mem_base + offset);
+
+	new_val = readl(pmc->gcr_mem_base + offset);
+	spin_unlock(&pmc->gcr_lock);
+
+	/* Check whether the bit update is successful */
+	return (new_val & mask) != (val & mask) ? -EIO : 0;
+}
+EXPORT_SYMBOL_GPL(intel_pmc_gcr_update);
+
+/**
+ * intel_pmc_s0ix_counter_read() - Read S0ix residency
+ * @pmc: PMC device pointer
+ * @data: Out param that contains current S0ix residency count.
+ *
+ * Writes to @data how many usecs the system has been in low-power S0ix
+ * state.
+ *
+ * Return: An error code or 0 on success.
+ */
+int intel_pmc_s0ix_counter_read(struct intel_pmc_dev *pmc, u64 *data)
+{
+	u64 deep, shlw;
+
+	spin_lock(&pmc->gcr_lock);
+	deep = readq(pmc->gcr_mem_base + PMC_GCR_TELEM_DEEP_S0IX_REG);
+	shlw = readq(pmc->gcr_mem_base + PMC_GCR_TELEM_SHLW_S0IX_REG);
+	spin_unlock(&pmc->gcr_lock);
+
+	*data = S0IX_RESIDENCY_IN_USECS(deep, shlw);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(intel_pmc_s0ix_counter_read);
+
+/**
+ * simplecmd_store() - Send a simple IPC command
+ * @dev: Device under the attribute is
+ * @attr: Attribute in question
+ * @buf: Buffer holding data to be stored to the attribute
+ * @count: Number of bytes in @buf
+ *
+ * Expects a string with two integers separated with space. These two
+ * values hold command and subcommand that is send to PMC.
+ *
+ * Return: Number number of bytes written (@count) or negative errno in
+ *	   case of error.
+ */
+static ssize_t simplecmd_store(struct device *dev, struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct intel_pmc_dev *pmc = dev_get_drvdata(dev);
+	struct intel_scu_ipc_dev *scu = pmc->scu;
+	int subcmd;
+	int cmd;
+	int ret;
+
+	ret = sscanf(buf, "%d %d", &cmd, &subcmd);
+	if (ret != 2) {
+		dev_err(dev, "Invalid values, expected: cmd subcmd\n");
+		return -EINVAL;
+	}
+
+	ret = intel_scu_ipc_dev_simple_command(scu, cmd, subcmd);
+	if (ret)
+		return ret;
+
+	return count;
+}
+static DEVICE_ATTR_WO(simplecmd);
+
+/**
+ * northpeak_store() - Enable or disable Northpeak
+ * @dev: Device under the attribute is
+ * @attr: Attribute in question
+ * @buf: Buffer holding data to be stored to the attribute
+ * @count: Number of bytes in @buf
+ *
+ * Expects an unsigned integer. Non-zero enables Northpeak and zero
+ * disables it.
+ *
+ * Return: Number number of bytes written (@count) or negative errno in
+ *	   case of error.
+ */
+static ssize_t northpeak_store(struct device *dev, struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct intel_pmc_dev *pmc = dev_get_drvdata(dev);
+	struct intel_scu_ipc_dev *scu = pmc->scu;
+	unsigned long val;
+	int subcmd;
+	int ret;
+
+	ret = kstrtoul(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	/* Northpeak is enabled if subcmd == 1 and disabled if it is 0 */
+	if (val)
+		subcmd = 1;
+	else
+		subcmd = 0;
+
+	ret = intel_scu_ipc_dev_simple_command(scu, PMC_NORTHPEAK_CTRL, subcmd);
+	if (ret)
+		return ret;
+
+	return count;
+}
+static DEVICE_ATTR_WO(northpeak);
+
+static struct attribute *intel_pmc_attrs[] = {
+	&dev_attr_northpeak.attr,
+	&dev_attr_simplecmd.attr,
+	NULL
+};
+
+static const struct attribute_group intel_pmc_group = {
+	.attrs = intel_pmc_attrs,
+};
+
+static const struct attribute_group *intel_pmc_groups[] = {
+	&intel_pmc_group,
+	NULL
+};
+
+static struct resource punit_res[6];
+
+static struct mfd_cell punit = {
+	.name = "intel_punit_ipc",
+	.resources = punit_res,
+};
+
+static struct itco_wdt_platform_data tco_pdata = {
+	.name = "Apollo Lake SoC",
+	.version = 5,
+	.no_reboot_use_pmc = true,
+};
+
+static struct resource tco_res[2];
+
+static const struct mfd_cell tco = {
+	.name = "iTCO_wdt",
+	.ignore_resource_conflicts = true,
+	.resources = tco_res,
+	.num_resources = ARRAY_SIZE(tco_res),
+	.platform_data = &tco_pdata,
+	.pdata_size = sizeof(tco_pdata),
+};
+
+static const struct resource telem_res[] = {
+	DEFINE_RES_MEM(TELEM_PUNIT_SSRAM_OFFSET, TELEM_SSRAM_SIZE),
+	DEFINE_RES_MEM(TELEM_PMC_SSRAM_OFFSET, TELEM_SSRAM_SIZE),
+};
+
+static const struct mfd_cell telem = {
+	.name = "intel_telemetry",
+	.resources = telem_res,
+	.num_resources = ARRAY_SIZE(telem_res),
+};
+
+static int intel_pmc_get_tco_resources(struct platform_device *pdev)
+{
+	struct resource *res;
+
+	if (acpi_has_watchdog())
+		return 0;
+
+	res = platform_get_resource(pdev, IORESOURCE_IO,
+				    PLAT_RESOURCE_ACPI_IO_INDEX);
+	if (!res) {
+		dev_err(&pdev->dev, "Failed to get IO resource\n");
+		return -EINVAL;
+	}
+
+	tco_res[0].flags = IORESOURCE_IO;
+	tco_res[0].start = res->start + TCO_BASE_OFFSET;
+	tco_res[0].end = tco_res[0].start + TCO_REGS_SIZE - 1;
+	tco_res[1].flags = IORESOURCE_IO;
+	tco_res[1].start = res->start + SMI_EN_OFFSET;
+	tco_res[1].end = tco_res[1].start + SMI_EN_SIZE - 1;
+
+	return 0;
+}
+
+static int intel_pmc_get_resources(struct platform_device *pdev,
+				   struct intel_pmc_dev *pmc,
+				   struct intel_scu_ipc_data *scu_data)
+{
+	struct resource gcr_res;
+	size_t npunit_res = 0;
+	struct resource *res;
+	int ret;
+
+	scu_data->irq = platform_get_irq_optional(pdev, 0);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM,
+				    PLAT_RESOURCE_IPC_INDEX);
+	if (!res) {
+		dev_err(&pdev->dev, "Failed to get IPC resource\n");
+		return -EINVAL;
+	}
+
+	/* IPC registers */
+	scu_data->mem.flags = res->flags;
+	scu_data->mem.start = res->start;
+	scu_data->mem.end = res->start + PLAT_RESOURCE_IPC_SIZE - 1;
+
+	/* GCR registers */
+	gcr_res.flags = res->flags;
+	gcr_res.start = res->start + PLAT_RESOURCE_GCR_OFFSET;
+	gcr_res.end = gcr_res.start + PLAT_RESOURCE_GCR_SIZE - 1;
+
+	pmc->gcr_mem_base = devm_ioremap_resource(&pdev->dev, &gcr_res);
+	if (IS_ERR(pmc->gcr_mem_base))
+		return PTR_ERR(pmc->gcr_mem_base);
+
+	/* Only register iTCO watchdog if there is no WDAT ACPI table */
+	ret = intel_pmc_get_tco_resources(pdev);
+	if (ret)
+		return ret;
+
+	/* BIOS data register */
+	res = platform_get_resource(pdev, IORESOURCE_MEM,
+				    PLAT_RESOURCE_BIOS_DATA_INDEX);
+	if (!res) {
+		dev_err(&pdev->dev, "Failed to get resource of P-unit BIOS data\n");
+		return -EINVAL;
+	}
+	punit_res[npunit_res++] = *res;
+
+	/* BIOS interface register */
+	res = platform_get_resource(pdev, IORESOURCE_MEM,
+				    PLAT_RESOURCE_BIOS_IFACE_INDEX);
+	if (!res) {
+		dev_err(&pdev->dev, "Failed to get resource of P-unit BIOS interface\n");
+		return -EINVAL;
+	}
+	punit_res[npunit_res++] = *res;
+
+	/* ISP data register, optional */
+	res = platform_get_resource(pdev, IORESOURCE_MEM,
+				    PLAT_RESOURCE_ISP_DATA_INDEX);
+	if (res)
+		punit_res[npunit_res++] = *res;
+
+	/* ISP interface register, optional */
+	res = platform_get_resource(pdev, IORESOURCE_MEM,
+				    PLAT_RESOURCE_ISP_IFACE_INDEX);
+	if (res)
+		punit_res[npunit_res++] = *res;
+
+	/* GTD data register, optional */
+	res = platform_get_resource(pdev, IORESOURCE_MEM,
+				    PLAT_RESOURCE_GTD_DATA_INDEX);
+	if (res)
+		punit_res[npunit_res++] = *res;
+
+	/* GTD interface register, optional */
+	res = platform_get_resource(pdev, IORESOURCE_MEM,
+				    PLAT_RESOURCE_GTD_IFACE_INDEX);
+	if (res)
+		punit_res[npunit_res++] = *res;
+
+	punit.num_resources = npunit_res;
+
+	/* Telemetry SSRAM is optional */
+	res = platform_get_resource(pdev, IORESOURCE_MEM,
+				    PLAT_RESOURCE_TELEM_SSRAM_INDEX);
+	if (res)
+		pmc->telem_base = res;
+
+	return 0;
+}
+
+static int intel_pmc_create_devices(struct intel_pmc_dev *pmc)
+{
+	int ret;
+
+	if (!acpi_has_watchdog()) {
+		ret = devm_mfd_add_devices(pmc->dev, PLATFORM_DEVID_AUTO, &tco,
+					   1, NULL, 0, NULL);
+		if (ret)
+			return ret;
+	}
+
+	ret = devm_mfd_add_devices(pmc->dev, PLATFORM_DEVID_AUTO, &punit, 1,
+				   NULL, 0, NULL);
+	if (ret)
+		return ret;
+
+	if (pmc->telem_base) {
+		ret = devm_mfd_add_devices(pmc->dev, PLATFORM_DEVID_AUTO,
+					   &telem, 1, pmc->telem_base, 0, NULL);
+	}
+
+	return ret;
+}
+
+static const struct acpi_device_id intel_pmc_acpi_ids[] = {
+	{ "INT34D2" },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, intel_pmc_acpi_ids);
+
+static int intel_pmc_probe(struct platform_device *pdev)
+{
+	struct intel_scu_ipc_data scu_data = {};
+	struct intel_pmc_dev *pmc;
+	int ret;
+
+	pmc = devm_kzalloc(&pdev->dev, sizeof(*pmc), GFP_KERNEL);
+	if (!pmc)
+		return -ENOMEM;
+
+	pmc->dev = &pdev->dev;
+	spin_lock_init(&pmc->gcr_lock);
+
+	ret = intel_pmc_get_resources(pdev, pmc, &scu_data);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to request resources\n");
+		return ret;
+	}
+
+	pmc->scu = devm_intel_scu_ipc_register(&pdev->dev, &scu_data);
+	if (IS_ERR(pmc->scu))
+		return PTR_ERR(pmc->scu);
+
+	platform_set_drvdata(pdev, pmc);
+
+	ret = intel_pmc_create_devices(pmc);
+	if (ret)
+		dev_err(&pdev->dev, "Failed to create PMC devices\n");
+
+	return ret;
+}
+
+static struct platform_driver intel_pmc_driver = {
+	.probe = intel_pmc_probe,
+	.driver = {
+		.name = "intel_pmc_bxt",
+		.acpi_match_table = intel_pmc_acpi_ids,
+		.dev_groups = intel_pmc_groups,
+	},
+};
+module_platform_driver(intel_pmc_driver);
+
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
+MODULE_AUTHOR("Zha Qipeng <qipeng.zha@intel.com>");
+MODULE_DESCRIPTION("Intel Broxton PMC driver");
+MODULE_LICENSE("GPL v2");