misc: smpro-misc: Add Ampere's Altra SMpro misc driver

Add driver support for accessing various information reported by
Ampere's SMpro co-processor such as Boot Progress and other
miscellaneous data.

Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
Link: https://lore.kernel.org/r/20221031024442.2490881-4-quan@os.amperecomputing.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-bus-platform-devices-ampere-smpro

@@ -262,3 +262,51 @@ Description:
 		For more details, see section `5.7 GPI Status Registers,
 		Altra Family Soc BMC Interface Specification`.
 
+What:		/sys/bus/platform/devices/smpro-misc.*/boot_progress
+KernelVersion:	6.1
+Contact:	Quan Nguyen <quan@os.amperecomputing.com>
+Description:
+		(RO) Contains the boot stages information in hex as format below::
+
+		    AABBCCCCCCCC
+
+		where:
+
+		  - ``AA``      : The boot stages
+
+		    - 00: SMpro firmware booting
+		    - 01: PMpro firmware booting
+		    - 02: ATF BL1 firmware booting
+		    - 03: DDR initialization
+		    - 04: DDR training report status
+		    - 05: ATF BL2 firmware booting
+		    - 06: ATF BL31 firmware booting
+		    - 07: ATF BL32 firmware booting
+		    - 08: UEFI firmware booting
+		    - 09: OS booting
+
+		  - ``BB``      : Boot status
+
+		    - 00: Not started
+		    - 01: Started
+		    - 02: Completed without error
+		    - 03: Failed.
+
+		  - ``CCCCCCCC``: Boot status information defined for each boot stages
+
+		For details, see section `5.11 Boot Stage Register Definitions`
+		and section `6. Processor Boot Progress Codes, Altra Family Soc BMC
+		Interface Specification`.
+
+
+What:		/sys/bus/platform/devices/smpro-misc*/soc_power_limit
+KernelVersion:	6.1
+Contact:	Quan Nguyen <quan@os.amperecomputing.com>
+Description:
+		(RW) Contains the desired SoC power limit in Watt.
+		Writes to this sysfs set the desired SoC power limit (W).
+		Reads from this register return the current SoC power limit (W).
+		The value ranges:
+
+		  - Minimum: 120 W
+		  - Maximum: Socket TDP power

drivers/misc/Kconfig

@@ -188,6 +188,16 @@ config SMPRO_ERRMON
 	  To compile this driver as a module, say M here. The driver will be
 	  called smpro-errmon.
 
+config SMPRO_MISC
+	tristate "Ampere Computing SMPro miscellaneous driver"
+	depends on MFD_SMPRO || COMPILE_TEST
+	help
+	  Say Y here to get support for the SMpro error miscellalenous function
+	  provided by Ampere Computing's Altra and Altra Max SoCs.
+
+	  To compile this driver as a module, say M here. The driver will be
+	  called smpro-misc.
+
 config CS5535_MFGPT
 	tristate "CS5535/CS5536 Geode Multi-Function General Purpose Timer (MFGPT) support"
 	depends on MFD_CS5535

drivers/misc/Makefile

@@ -24,6 +24,7 @@ obj-$(CONFIG_KGDB_TESTS)	+= kgdbts.o
 obj-$(CONFIG_SGI_XP)		+= sgi-xp/
 obj-$(CONFIG_SGI_GRU)		+= sgi-gru/
 obj-$(CONFIG_SMPRO_ERRMON)	+= smpro-errmon.o
+obj-$(CONFIG_SMPRO_MISC)	+= smpro-misc.o
 obj-$(CONFIG_CS5535_MFGPT)	+= cs5535-mfgpt.o
 obj-$(CONFIG_GEHC_ACHC)		+= gehc-achc.o
 obj-$(CONFIG_HP_ILO)		+= hpilo.o

drivers/misc/smpro-misc.c

@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Ampere Computing SoC's SMpro Misc Driver
+ *
+ * Copyright (c) 2022, Ampere Computing LLC
+ */
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/* Boot Stage/Progress Registers */
+#define BOOTSTAGE	0xB0
+#define BOOTSTAGE_LO	0xB1
+#define CUR_BOOTSTAGE	0xB2
+#define BOOTSTAGE_HI	0xB3
+
+/* SOC State Registers */
+#define SOC_POWER_LIMIT		0xE5
+
+struct smpro_misc {
+	struct regmap *regmap;
+};
+
+static ssize_t boot_progress_show(struct device *dev, struct device_attribute *da, char *buf)
+{
+	struct smpro_misc *misc = dev_get_drvdata(dev);
+	u16 boot_progress[3] = { 0 };
+	u32 bootstage;
+	u8 boot_stage;
+	u8 cur_stage;
+	u32 reg_lo;
+	u32 reg;
+	int ret;
+
+	/* Read current boot stage */
+	ret = regmap_read(misc->regmap, CUR_BOOTSTAGE, &reg);
+	if (ret)
+		return ret;
+
+	cur_stage = reg & 0xff;
+
+	ret = regmap_read(misc->regmap, BOOTSTAGE, &bootstage);
+	if (ret)
+		return ret;
+
+	boot_stage = (bootstage >> 8) & 0xff;
+
+	if (boot_stage > cur_stage)
+		return -EINVAL;
+
+	ret = regmap_read(misc->regmap,	BOOTSTAGE_LO, &reg_lo);
+	if (!ret)
+		ret = regmap_read(misc->regmap, BOOTSTAGE_HI, &reg);
+	if (ret)
+		return ret;
+
+	/* Firmware to report new boot stage next time */
+	if (boot_stage < cur_stage) {
+		ret = regmap_write(misc->regmap, BOOTSTAGE, ((bootstage & 0xff00) | 0x1));
+		if (ret)
+			return ret;
+	}
+
+	boot_progress[0] = bootstage;
+	boot_progress[1] = swab16(reg);
+	boot_progress[2] = swab16(reg_lo);
+
+	return sysfs_emit(buf, "%*phN\n", (int)sizeof(boot_progress), boot_progress);
+}
+
+static DEVICE_ATTR_RO(boot_progress);
+
+static ssize_t soc_power_limit_show(struct device *dev, struct device_attribute *da, char *buf)
+{
+	struct smpro_misc *misc = dev_get_drvdata(dev);
+	unsigned int value;
+	int ret;
+
+	ret = regmap_read(misc->regmap, SOC_POWER_LIMIT, &value);
+	if (ret)
+		return ret;
+
+	return sysfs_emit(buf, "%d\n", value);
+}
+
+static ssize_t soc_power_limit_store(struct device *dev, struct device_attribute *da,
+				     const char *buf, size_t count)
+{
+	struct smpro_misc *misc = dev_get_drvdata(dev);
+	unsigned long val;
+	s32 ret;
+
+	ret = kstrtoul(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(misc->regmap, SOC_POWER_LIMIT, (unsigned int)val);
+	if (ret)
+		return -EPROTO;
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(soc_power_limit);
+
+static struct attribute *smpro_misc_attrs[] = {
+	&dev_attr_boot_progress.attr,
+	&dev_attr_soc_power_limit.attr,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(smpro_misc);
+
+static int smpro_misc_probe(struct platform_device *pdev)
+{
+	struct smpro_misc *misc;
+
+	misc = devm_kzalloc(&pdev->dev, sizeof(struct smpro_misc), GFP_KERNEL);
+	if (!misc)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, misc);
+
+	misc->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!misc->regmap)
+		return -ENODEV;
+
+	return 0;
+}
+
+static struct platform_driver smpro_misc_driver = {
+	.probe		= smpro_misc_probe,
+	.driver = {
+		.name	= "smpro-misc",
+		.dev_groups = smpro_misc_groups,
+	},
+};
+
+module_platform_driver(smpro_misc_driver);
+
+MODULE_AUTHOR("Tung Nguyen <tungnguyen@os.amperecomputing.com>");
+MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
+MODULE_DESCRIPTION("Ampere Altra SMpro Misc driver");
+MODULE_LICENSE("GPL");