[PATCH v10 3/3] misc: smpro-misc: Add Ampere's Altra SMpro misc driver

From: Quan Nguyen
Date: Sun Oct 30 2022 - 22:45:55 EST

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@xxxxxxxxxxxxxxxxxxxxxx>
---
Changes in v10:
+ Fix document format [Bagas]
+ Update commit message: s/This commit adds/Add/ [Bagas]
+ Only use Documentation/ABI/ [Greg]
+ Drop Documentation/misc-devices/smpro-misc.rst [Greg]

Changes in v9:
+ Update SPDX licence [Greg]
+ Use ATTRIBUTE_GROUPS() [Greg]
+ Use dev_groups instead of sysfs_create_group() to avoid
racing issue with user space [Greg]
+ Refactor code to avoid clever encoding issue [Quan]

Changes in v8:
+ Update wording for SMPRO_MISC in Kconfig file [Quan]
+ Switch to use sysfs_emit() [Quan]

Changes in v7:
+ Fix wrong return type of *_show/store()
functions [kernel robot test]
+ Adjust patch order to remove dependence with
smpro-mfd [Lee Jones]

Changes in v6:
+ First introduced in v6 [Quan]
---
.../sysfs-bus-platform-devices-ampere-smpro | 48 ++++++
drivers/misc/Kconfig | 10 ++
drivers/misc/Makefile | 1 +
drivers/misc/smpro-misc.c | 145 ++++++++++++++++++
4 files changed, 204 insertions(+)
create mode 100644 drivers/misc/smpro-misc.c

diff --git a/Documentation/ABI/testing/sysfs-bus-platform-devices-ampere-smpro b/Documentation/ABI/testing/sysfs-bus-platform-devices-ampere-smpro
index 2b84dc8c3149..ca93c215ef99 100644
--- a/Documentation/ABI/testing/sysfs-bus-platform-devices-ampere-smpro
+++ b/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@xxxxxxxxxxxxxxxxxxxxxx>
+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@xxxxxxxxxxxxxxxxxxxxxx>
+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
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index b9ceee949dab..9947b7892bd5 100644
--- a/drivers/misc/Kconfig
+++ b/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
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index bbe24d4511a3..87b54a4a4422 100644
--- a/drivers/misc/Makefile
+++ b/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
diff --git a/drivers/misc/smpro-misc.c b/drivers/misc/smpro-misc.c
new file mode 100644
index 000000000000..6c427141e51b
--- /dev/null
+++ b/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@xxxxxxxxxxxxxxxxxxxxxx>");
+MODULE_AUTHOR("Quan Nguyen <quan@xxxxxxxxxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Ampere Altra SMpro Misc driver");
+MODULE_LICENSE("GPL");
--
2.35.1