SoC attributes update for v5.9

1. Addition of ARM SMCCC ARCH_SOC_ID support
 2. Usage of the custom soc attribute groups already supported in the
    infrastucture instead of device_create_file which eliminates the need
    for any cleanup when soc is unregistered
 3. Minor clean up switching to use standard DEVICE_ATTR_RO() instead of
    direct __ATTR
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Merge tag 'soc-attr-updates-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into arm/drivers

SoC attributes update for v5.9

1. Addition of ARM SMCCC ARCH_SOC_ID support
2. Usage of the custom soc attribute groups already supported in the
   infrastucture instead of device_create_file which eliminates the need
   for any cleanup when soc is unregistered
3. Minor clean up switching to use standard DEVICE_ATTR_RO() instead of
   direct __ATTR

* tag 'soc-attr-updates-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
  firmware: smccc: Add ARCH_SOC_ID support
  ARM: OMAP2: Use custom soc attribute group instead of device_create_file
  ARM: OMAP2: Switch to use DEVICE_ATTR_RO()
  soc: ux500: Use custom soc attribute group instead of device_create_file
  soc: ux500: Switch to use DEVICE_ATTR_RO()
  soc: integrator: Use custom soc attribute group instead of device_create_file
  soc: integrator: Switch to use DEVICE_ATTR_RO()
  soc: realview: Use custom soc attribute group instead of device_create_file
  soc: realview: Switch to use DEVICE_ATTR_RO()

Link: https://lore.kernel.org/r/20200706165312.40697-1-sudeep.holla@arm.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Documentation/ABI/testing/sysfs-devices-soc

@@ -26,6 +26,30 @@ Description:
 		Read-only attribute common to all SoCs. Contains SoC family name
 		(e.g. DB8500).
 
+		On many of ARM based silicon with SMCCC v1.2+ compliant firmware
+		this will contain the JEDEC JEP106 manufacturer’s identification
+		code. The format is "jep106:XXYY" where XX is identity code and
+		YY is continuation code.
+
+		This manufacturer’s identification code is defined by one
+		or more eight (8) bit fields, each consisting of seven (7)
+		data bits plus one (1) odd parity bit. It is a single field,
+		limiting the possible number of vendors to 126. To expand
+		the maximum number of identification codes, a continuation
+		scheme has been defined.
+
+		The specified mechanism is that an identity code of 0x7F
+		represents the "continuation code" and implies the presence
+		of an additional identity code field, and this mechanism
+		may be extended to multiple continuation codes followed
+		by the manufacturer's identity code.
+
+		For example, ARM has identity code 0x7F 0x7F 0x7F 0x7F 0x3B,
+		which is code 0x3B on the fifth 'page'. This is shortened
+		as JEP106 identity code of 0x3B and a continuation code of
+		0x4 to represent the four continuation codes preceding the
+		identity code.
+
 What:		/sys/devices/socX/serial_number
 Date:		January 2019
 contact:	Bjorn Andersson <bjorn.andersson@linaro.org>
@@ -40,6 +64,12 @@ Description:
 		Read-only attribute supported by most SoCs. In the case of
 		ST-Ericsson's chips this contains the SoC serial number.
 
+		On many of ARM based silicon with SMCCC v1.2+ compliant firmware
+		this will contain the SOC ID appended to the family attribute
+		to ensure there is no conflict in this namespace across various
+		vendors. The format is "jep106:XXYY:ZZZZ" where XX is identity
+		code, YY is continuation code and ZZZZ is the SOC ID.
+
 What:		/sys/devices/socX/revision
 Date:		January 2012
 contact:	Lee Jones <lee.jones@linaro.org>

arch/arm/mach-omap2/id.c

@@ -775,19 +775,23 @@ static const char * __init omap_get_family(void)
 		return kasprintf(GFP_KERNEL, "Unknown");
 }
 
-static ssize_t omap_get_type(struct device *dev,
-					struct device_attribute *attr,
-					char *buf)
+static ssize_t
+type_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", omap_types[omap_type()]);
 }
 
-static struct device_attribute omap_soc_attr =
-	__ATTR(type,  S_IRUGO, omap_get_type,  NULL);
+static DEVICE_ATTR_RO(type);
+
+static struct attribute *omap_soc_attrs[] = {
+	&dev_attr_type.attr,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(omap_soc);
 
 void __init omap_soc_device_init(void)
 {
-	struct device *parent;
 	struct soc_device *soc_dev;
 	struct soc_device_attribute *soc_dev_attr;
 
@@ -798,14 +802,12 @@ void __init omap_soc_device_init(void)
 	soc_dev_attr->machine  = soc_name;
 	soc_dev_attr->family   = omap_get_family();
 	soc_dev_attr->revision = soc_rev;
+	soc_dev_attr->custom_attr_group = omap_soc_groups[0];
 
 	soc_dev = soc_device_register(soc_dev_attr);
 	if (IS_ERR(soc_dev)) {
 		kfree(soc_dev_attr);
 		return;
 	}
-
-	parent = soc_device_to_device(soc_dev);
-	device_create_file(parent, &omap_soc_attr);
 }
 #endif /* CONFIG_SOC_BUS */

drivers/firmware/smccc/Kconfig

@@ -14,3 +14,12 @@ config HAVE_ARM_SMCCC_DISCOVERY
 	 to add SMCCC discovery mechanism though the PSCI firmware
 	 implementation of PSCI_FEATURES(SMCCC_VERSION) which returns
 	 success on firmware compliant to SMCCC v1.1 and above.
+
+config ARM_SMCCC_SOC_ID
+	bool "SoC bus device for the ARM SMCCC SOC_ID"
+	depends on HAVE_ARM_SMCCC_DISCOVERY
+	default y
+	select SOC_BUS
+	help
+	  Include support for the SoC bus on the ARM SMCCC firmware based
+	  platforms providing some sysfs information about the SoC variant.

drivers/firmware/smccc/Makefile

@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 #
 obj-$(CONFIG_HAVE_ARM_SMCCC_DISCOVERY)	+= smccc.o
+obj-$(CONFIG_ARM_SMCCC_SOC_ID)	+= soc_id.o

drivers/firmware/smccc/soc_id.c

@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2020 Arm Limited
+ */
+
+#define pr_fmt(fmt) "SMCCC: SOC_ID: " fmt
+
+#include <linux/arm-smccc.h>
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
+
+#define SMCCC_SOC_ID_JEP106_BANK_IDX_MASK	GENMASK(30, 24)
+/*
+ * As per the SMC Calling Convention specification v1.2 (ARM DEN 0028C)
+ * Section 7.4 SMCCC_ARCH_SOC_ID bits[23:16] are JEP-106 identification
+ * code with parity bit for the SiP. We can drop the parity bit.
+ */
+#define SMCCC_SOC_ID_JEP106_ID_CODE_MASK	GENMASK(22, 16)
+#define SMCCC_SOC_ID_IMP_DEF_SOC_ID_MASK	GENMASK(15, 0)
+
+#define JEP106_BANK_CONT_CODE(x)	\
+	(u8)(FIELD_GET(SMCCC_SOC_ID_JEP106_BANK_IDX_MASK, (x)))
+#define JEP106_ID_CODE(x)	\
+	(u8)(FIELD_GET(SMCCC_SOC_ID_JEP106_ID_CODE_MASK, (x)))
+#define IMP_DEF_SOC_ID(x)	\
+	(u16)(FIELD_GET(SMCCC_SOC_ID_IMP_DEF_SOC_ID_MASK, (x)))
+
+static struct soc_device *soc_dev;
+static struct soc_device_attribute *soc_dev_attr;
+
+static int __init smccc_soc_init(void)
+{
+	struct arm_smccc_res res;
+	int soc_id_rev, soc_id_version;
+	static char soc_id_str[20], soc_id_rev_str[12];
+	static char soc_id_jep106_id_str[12];
+
+	if (arm_smccc_get_version() < ARM_SMCCC_VERSION_1_2)
+		return 0;
+
+	if (arm_smccc_1_1_get_conduit() == SMCCC_CONDUIT_NONE) {
+		pr_err("%s: invalid SMCCC conduit\n", __func__);
+		return -EOPNOTSUPP;
+	}
+
+	arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
+			     ARM_SMCCC_ARCH_SOC_ID, &res);
+
+	if (res.a0 == SMCCC_RET_NOT_SUPPORTED) {
+		pr_info("ARCH_SOC_ID not implemented, skipping ....\n");
+		return 0;
+	}
+
+	if ((int)res.a0 < 0) {
+		pr_info("ARCH_FEATURES(ARCH_SOC_ID) returned error: %lx\n",
+			res.a0);
+		return -EINVAL;
+	}
+
+	arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 0, &res);
+	if ((int)res.a0 < 0) {
+		pr_err("ARCH_SOC_ID(0) returned error: %lx\n", res.a0);
+		return -EINVAL;
+	}
+
+	soc_id_version = res.a0;
+
+	arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 1, &res);
+	if ((int)res.a0 < 0) {
+		pr_err("ARCH_SOC_ID(1) returned error: %lx\n", res.a0);
+		return -EINVAL;
+	}
+
+	soc_id_rev = res.a0;
+
+	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+	if (!soc_dev_attr)
+		return -ENOMEM;
+
+	sprintf(soc_id_rev_str, "0x%08x", soc_id_rev);
+	sprintf(soc_id_jep106_id_str, "jep106:%02x%02x",
+		JEP106_BANK_CONT_CODE(soc_id_version),
+		JEP106_ID_CODE(soc_id_version));
+	sprintf(soc_id_str, "%s:%04x", soc_id_jep106_id_str,
+		IMP_DEF_SOC_ID(soc_id_version));
+
+	soc_dev_attr->soc_id = soc_id_str;
+	soc_dev_attr->revision = soc_id_rev_str;
+	soc_dev_attr->family = soc_id_jep106_id_str;
+
+	soc_dev = soc_device_register(soc_dev_attr);
+	if (IS_ERR(soc_dev)) {
+		kfree(soc_dev_attr);
+		return PTR_ERR(soc_dev);
+	}
+
+	pr_info("ID = %s Revision = %s\n", soc_dev_attr->soc_id,
+		soc_dev_attr->revision);
+
+	return 0;
+}
+module_init(smccc_soc_init);
+
+static void __exit smccc_soc_exit(void)
+{
+	if (soc_dev)
+		soc_device_unregister(soc_dev);
+	kfree(soc_dev_attr);
+}
+module_exit(smccc_soc_exit);

drivers/soc/ux500/ux500-soc-id.c

@@ -146,9 +146,8 @@ static const char * __init ux500_get_revision(void)
 	return kasprintf(GFP_KERNEL, "%s", "Unknown");
 }
 
-static ssize_t ux500_get_process(struct device *dev,
-					struct device_attribute *attr,
-					char *buf)
+static ssize_t
+process_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	if (dbx500_id.process == 0x00)
 		return sprintf(buf, "Standard\n");
@@ -156,6 +155,15 @@ static ssize_t ux500_get_process(struct device *dev,
 	return sprintf(buf, "%02xnm\n", dbx500_id.process);
 }
 
+static DEVICE_ATTR_RO(process);
+
+static struct attribute *ux500_soc_attrs[] = {
+	&dev_attr_process.attr,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(ux500_soc);
+
 static const char *db8500_read_soc_id(struct device_node *backupram)
 {
 	void __iomem *base;
@@ -184,14 +192,11 @@ static void __init soc_info_populate(struct soc_device_attribute *soc_dev_attr,
 	soc_dev_attr->machine  = ux500_get_machine();
 	soc_dev_attr->family   = ux500_get_family();
 	soc_dev_attr->revision = ux500_get_revision();
+	soc_dev_attr->custom_attr_group = ux500_soc_groups[0];
 }
 
-static const struct device_attribute ux500_soc_attr =
-	__ATTR(process,  S_IRUGO, ux500_get_process,  NULL);
-
 static int __init ux500_soc_device_init(void)
 {
-	struct device *parent;
 	struct soc_device *soc_dev;
 	struct soc_device_attribute *soc_dev_attr;
 	struct device_node *backupram;
@@ -217,9 +222,6 @@ static int __init ux500_soc_device_init(void)
 		return PTR_ERR(soc_dev);
 	}
 
-	parent = soc_device_to_device(soc_dev);
-	device_create_file(parent, &ux500_soc_attr);
-
 	return 0;
 }
 subsys_initcall(ux500_soc_device_init);

drivers/soc/versatile/soc-integrator.c

@@ -56,45 +56,47 @@ static const char *integrator_fpga_str(u32 id)
 	}
 }
 
-static ssize_t integrator_get_manf(struct device *dev,
-			      struct device_attribute *attr,
-			      char *buf)
+static ssize_t
+manufacturer_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%02x\n", integrator_coreid >> 24);
 }
 
-static struct device_attribute integrator_manf_attr =
-	__ATTR(manufacturer,  S_IRUGO, integrator_get_manf,  NULL);
+static DEVICE_ATTR_RO(manufacturer);
 
-static ssize_t integrator_get_arch(struct device *dev,
-			      struct device_attribute *attr,
-			      char *buf)
+static ssize_t
+arch_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", integrator_arch_str(integrator_coreid));
 }
 
-static struct device_attribute integrator_arch_attr =
-	__ATTR(arch,  S_IRUGO, integrator_get_arch,  NULL);
+static DEVICE_ATTR_RO(arch);
 
-static ssize_t integrator_get_fpga(struct device *dev,
-			      struct device_attribute *attr,
-			      char *buf)
+static ssize_t
+fpga_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", integrator_fpga_str(integrator_coreid));
 }
 
-static struct device_attribute integrator_fpga_attr =
-	__ATTR(fpga,  S_IRUGO, integrator_get_fpga,  NULL);
+static DEVICE_ATTR_RO(fpga);
 
-static ssize_t integrator_get_build(struct device *dev,
-			       struct device_attribute *attr,
-			       char *buf)
+static ssize_t
+build_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%02x\n", (integrator_coreid >> 4) & 0xFF);
 }
 
-static struct device_attribute integrator_build_attr =
-	__ATTR(build,  S_IRUGO, integrator_get_build,  NULL);
+static DEVICE_ATTR_RO(build);
+
+static struct attribute *integrator_attrs[] = {
+	&dev_attr_manufacturer.attr,
+	&dev_attr_arch.attr,
+	&dev_attr_fpga.attr,
+	&dev_attr_build.attr,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(integrator);
 
 static int __init integrator_soc_init(void)
 {
@@ -127,6 +129,7 @@ static int __init integrator_soc_init(void)
 	soc_dev_attr->soc_id = "Integrator";
 	soc_dev_attr->machine = "Integrator";
 	soc_dev_attr->family = "Versatile";
+	soc_dev_attr->custom_attr_group = integrator_groups[0];
 	soc_dev = soc_device_register(soc_dev_attr);
 	if (IS_ERR(soc_dev)) {
 		kfree(soc_dev_attr);
@@ -134,11 +137,6 @@ static int __init integrator_soc_init(void)
 	}
 	dev = soc_device_to_device(soc_dev);
 
-	device_create_file(dev, &integrator_manf_attr);
-	device_create_file(dev, &integrator_arch_attr);
-	device_create_file(dev, &integrator_fpga_attr);
-	device_create_file(dev, &integrator_build_attr);
-
 	dev_info(dev, "Detected ARM core module:\n");
 	dev_info(dev, "    Manufacturer: %02x\n", (val >> 24));
 	dev_info(dev, "    Architecture: %s\n", integrator_arch_str(val));

drivers/soc/versatile/soc-realview.c

@@ -39,45 +39,47 @@ static const char *realview_arch_str(u32 id)
 	}
 }
 
-static ssize_t realview_get_manf(struct device *dev,
-			      struct device_attribute *attr,
-			      char *buf)
+static ssize_t
+manufacturer_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%02x\n", realview_coreid >> 24);
 }
 
-static struct device_attribute realview_manf_attr =
-	__ATTR(manufacturer,  S_IRUGO, realview_get_manf,  NULL);
+static DEVICE_ATTR_RO(manufacturer);
 
-static ssize_t realview_get_board(struct device *dev,
-			      struct device_attribute *attr,
-			      char *buf)
+static ssize_t
+board_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "HBI-%03x\n", ((realview_coreid >> 16) & 0xfff));
 }
 
-static struct device_attribute realview_board_attr =
-	__ATTR(board,  S_IRUGO, realview_get_board,  NULL);
+static DEVICE_ATTR_RO(board);
 
-static ssize_t realview_get_arch(struct device *dev,
-			      struct device_attribute *attr,
-			      char *buf)
+static ssize_t
+fpga_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", realview_arch_str(realview_coreid));
 }
 
-static struct device_attribute realview_arch_attr =
-	__ATTR(fpga,  S_IRUGO, realview_get_arch,  NULL);
+static DEVICE_ATTR_RO(fpga);
 
-static ssize_t realview_get_build(struct device *dev,
-			       struct device_attribute *attr,
-			       char *buf)
+static ssize_t
+build_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%02x\n", (realview_coreid & 0xFF));
 }
 
-static struct device_attribute realview_build_attr =
-	__ATTR(build,  S_IRUGO, realview_get_build,  NULL);
+static DEVICE_ATTR_RO(build);
+
+static struct attribute *realview_attrs[] = {
+	&dev_attr_manufacturer.attr,
+	&dev_attr_board.attr,
+	&dev_attr_fpga.attr,
+	&dev_attr_build.attr,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(realview);
 
 static int realview_soc_probe(struct platform_device *pdev)
 {
@@ -102,6 +104,7 @@ static int realview_soc_probe(struct platform_device *pdev)
 
 	soc_dev_attr->machine = "RealView";
 	soc_dev_attr->family = "Versatile";
+	soc_dev_attr->custom_attr_group = realview_groups[0];
 	soc_dev = soc_device_register(soc_dev_attr);
 	if (IS_ERR(soc_dev)) {
 		kfree(soc_dev_attr);
@@ -112,11 +115,6 @@ static int realview_soc_probe(struct platform_device *pdev)
 	if (ret)
 		return -ENODEV;
 
-	device_create_file(soc_device_to_device(soc_dev), &realview_manf_attr);
-	device_create_file(soc_device_to_device(soc_dev), &realview_board_attr);
-	device_create_file(soc_device_to_device(soc_dev), &realview_arch_attr);
-	device_create_file(soc_device_to_device(soc_dev), &realview_build_attr);
-
 	dev_info(&pdev->dev, "RealView Syscon Core ID: 0x%08x, HBI-%03x\n",
 		 realview_coreid,
 		 ((realview_coreid >> 16) & 0xfff));

include/linux/arm-smccc.h

@@ -71,6 +71,11 @@
 			   ARM_SMCCC_SMC_32,				\
 			   0, 1)
 
+#define ARM_SMCCC_ARCH_SOC_ID						\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_32,				\
+			   0, 2)
+
 #define ARM_SMCCC_ARCH_WORKAROUND_1					\
 	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
 			   ARM_SMCCC_SMC_32,				\