[V1 2/2] drivers soc: add support for ST stm32mp13xx family

[Rodolfo Giometti]

This patch adds SoC support for the ST stm32mp13xx family. It also
adds the special attribute "secure" which returns the CPU's secure
mode status.

Signed-off-by: Rodolfo Giometti <giometti@xxxxxxxxxxxx>
---
 drivers/soc/st/Makefile        |   1 +
 drivers/soc/st/soc-stm32mp13.c | 253 +++++++++++++++++++++++++++++++++
 2 files changed, 254 insertions(+)
 create mode 100644 drivers/soc/st/soc-stm32mp13.c

diff --git a/drivers/soc/st/Makefile b/drivers/soc/st/Makefile
index 6c71607f6c89..c84bf510928d 100644
--- a/drivers/soc/st/Makefile
+++ b/drivers/soc/st/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_STM32_PM_DOMAINS) += stm32_pm_domain.o
 obj-$(CONFIG_STM32_RISAB) += stm32_risab.o
 obj-$(CONFIG_STM32_RISAF) += stm32_risaf.o
+obj-$(CONFIG_MACH_STM32MP13) += soc-stm32mp13.o
diff --git a/drivers/soc/st/soc-stm32mp13.c b/drivers/soc/st/soc-stm32mp13.c
new file mode 100644
index 000000000000..cf45dbeb926a
--- /dev/null
+++ b/drivers/soc/st/soc-stm32mp13.c
@@ -0,0 +1,253 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2025 Rodolfo Giometti <giometti@xxxxxxxxxxxx>
+ */
+
+#include <linux/cpu.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
+
+#define STM32MP131A	0x6C9
+#define STM32MP131C	0x6C8
+#define STM32MP131D	0xEC9
+#define STM32MP131F	0xEC8
+#define STM32MP133A	0x0C1
+#define STM32MP133C	0x0C0
+#define STM32MP133D	0x8C1
+#define STM32MP133F	0x8C0
+#define STM32MP135A	0x001
+#define STM32MP135C	0x000
+#define STM32MP135D	0x801
+#define STM32MP135F	0x800
+
+#define BSEC_RPN	0x204
+#define BSEC_UID	0x234
+#define SYSCFG_IDC	0x380
+
+/*
+ * SoC attributes
+ */
+
+static ssize_t
+secure_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	u16 val;
+	char *str;
+	int ret;
+	struct device *cpu_dev;
+
+	cpu_dev = get_cpu_device(0);
+	if (!cpu_dev) {
+		dev_err(dev, "failed to get cpu0 device\n");
+		return -ENODEV;
+	}
+	ret = nvmem_cell_read_u16(cpu_dev, "encoding_mode", &val);
+	if (ret)
+		return ret;
+
+	switch (val) {
+	case 0b0000010111:
+		str = "open";
+		break;
+	case 0b0000111111:
+		str = "closed";
+		break;
+	case 0b0101111111:
+		str = "closed boundary-scan-disabled]";
+		break;
+	case 0b1111111111:
+		str = "closed JTAG-disabled";
+		break;
+	default:
+		str = "unknown";
+	}
+
+	return sprintf(buf, "%s\n", str);
+}
+static DEVICE_ATTR_RO(secure);
+
+static struct attribute *stm32mp13_soc_attrs[] = {
+	&dev_attr_secure.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(stm32mp13_soc);
+
+/*
+ * Driver init functions
+ */
+
+static int __init stm32mp13_soc_get_rpn_uid(u32 *rpn, u32 uid[3])
+{
+	struct device_node *np;
+	void __iomem *regs;
+	static const struct of_device_id devids[] = {
+		{ .compatible = "st,stm32mp13-bsec" },
+		{ },
+	};
+
+	np = of_find_matching_node(NULL, devids);
+	if (!np)
+		return -ENODEV;
+
+	regs = of_iomap(np, 0);
+	of_node_put(np);
+
+	if (!regs) {
+		pr_warn("Could not map BSEC iomem range");
+		return -ENXIO;
+	}
+
+	*rpn = readl(regs + BSEC_RPN) & 0x0fff;
+	uid[0] = readl(regs + BSEC_UID + 0);
+	uid[1] = readl(regs + BSEC_UID + 4);
+	uid[2] = readl(regs + BSEC_UID + 8);
+
+	iounmap(regs);
+
+	return 0;
+}
+
+static int __init stm32mp13_soc_get_idc(u32 *idc)
+{
+	struct device_node *np;
+	void __iomem *regs;
+	static const struct of_device_id devids[] = {
+		{ .compatible = "st,stm32mp157-syscfg" },
+		{ },
+	};
+
+	np = of_find_matching_node(NULL, devids);
+	if (!np)
+		return -ENODEV;
+
+	regs = of_iomap(np, 0);
+	of_node_put(np);
+
+	if (!regs) {
+		pr_warn("Could not map BSEC iomem range");
+		return -ENXIO;
+	}
+
+	*idc = readl(regs + SYSCFG_IDC);
+
+	iounmap(regs);
+
+	return 0;
+}
+
+static int __init stm32mp13_soc_device_init(void)
+{
+	u32 part_number, rev, chipid[3];
+	struct soc_device_attribute *soc_dev_attr;
+	struct soc_device *soc_dev;
+	struct device_node *root;
+	const char *soc_id;
+	int ret;
+
+	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+	if (!soc_dev_attr)
+		return -ENOMEM;
+	soc_dev_attr->family = "STM STM32MP13xx";
+
+	root = of_find_node_by_path("/");
+	ret = of_property_read_string(root, "model", &soc_dev_attr->machine);
+	if (ret)
+		of_property_read_string_index(root, "compatible", 0,
+						&soc_dev_attr->machine);
+	of_node_put(root);
+	if (ret)
+		goto free_soc;
+
+	/* Get chip info */
+	ret = stm32mp13_soc_get_rpn_uid(&part_number, chipid);
+	if (ret) {
+		pr_err("failed to get chip part number: %d\n", ret);
+		goto free_soc;
+	}
+	switch (part_number) {
+	case STM32MP131A:
+		soc_id = "131a";
+		break;
+	case STM32MP131C:
+		soc_id = "131c";
+		break;
+	case STM32MP131D:
+		soc_id = "131d";
+		break;
+	case STM32MP131F:
+		soc_id = "131f";
+		break;
+	case STM32MP133A:
+		soc_id = "133a";
+		break;
+	case STM32MP133C:
+		soc_id = "133c";
+		break;
+	case STM32MP133D:
+		soc_id = "133d";
+		break;
+	case STM32MP133F:
+		soc_id = "133f";
+		break;
+	case STM32MP135A:
+		soc_id = "135a";
+		break;
+	case STM32MP135C:
+		soc_id = "135c";
+		break;
+	case STM32MP135D:
+		soc_id = "135d";
+		break;
+	case STM32MP135F:
+		soc_id = "135f";
+		break;
+	default:
+		soc_id = "unknown";
+	}
+	soc_dev_attr->soc_id = soc_id;
+
+	ret = stm32mp13_soc_get_idc(&rev);
+	if (ret)
+		goto free_soc;
+	soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%X", rev >> 16);
+	if (!soc_dev_attr->revision) {
+		ret = -ENOMEM;
+		goto free_soc;
+	}
+
+	soc_dev_attr->serial_number = kasprintf(GFP_KERNEL, "%08X%08X%08X",
+					chipid[0], chipid[1], chipid[2]);
+	if (!soc_dev_attr->serial_number) {
+		ret = -ENOMEM;
+		goto free_rev;
+	}
+
+	/* Add custom attributes group */
+	soc_dev_attr->custom_attr_group = stm32mp13_soc_groups[0];
+
+	/* Register the SOC device */
+	soc_dev = soc_device_register(soc_dev_attr);
+	if (IS_ERR(soc_dev)) {
+		ret = PTR_ERR(soc_dev);
+		goto free_serial_number;
+	}
+
+	pr_info("SoC Machine: %s\n", soc_dev_attr->machine);
+	pr_info("SoC family: %s\n", soc_dev_attr->family);
+	pr_info("SoC ID: %s, Revision: %s\n",
+		soc_dev_attr->soc_id, soc_dev_attr->revision);
+
+	return 0;
+
+free_serial_number:
+	kfree(soc_dev_attr->serial_number);
+free_rev:
+	kfree(soc_dev_attr->revision);
+free_soc:
+	kfree(soc_dev_attr);
+	return ret;
+}
+device_initcall(stm32mp13_soc_device_init);
-- 
2.25.1