[PATCH v9 5/9] misc: smpro-misc: Add Ampere's Altra SMpro misc driver

From: Quan Nguyen
Date: Thu Sep 29 2022 - 05:44:50 EST

This commit adds 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 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]

drivers/misc/Kconfig | 10 +++
drivers/misc/Makefile | 1 +
drivers/misc/smpro-misc.c | 145 ++++++++++++++++++++++++++++++++++++++
3 files changed, 156 insertions(+)
create mode 100644 drivers/misc/smpro-misc.c

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