ARM: zynq: Add support for SOC_BUS

Provide information through SOC_BUS to user space.
Silicon revision is provided through devcfg device.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/boot/dts/zynq-7000.dtsi

@@ -154,6 +154,11 @@ clkc: clkc@100 {
 			};
 		};
 
+		devcfg: devcfg@f8007000 {
+			compatible = "xlnx,zynq-devcfg-1.0";
+			reg = <0xf8007000 0x100>;
+		} ;
+
 		global_timer: timer@f8f00200 {
 			compatible = "arm,cortex-a9-global-timer";
 			reg = <0xf8f00200 0x20>;

arch/arm/mach-zynq/Kconfig

@@ -10,5 +10,6 @@ config ARCH_ZYNQ
 	select CADENCE_TTC_TIMER
 	select ARM_GLOBAL_TIMER if !CPU_FREQ
 	select MFD_SYSCON
+	select SOC_BUS
 	help
 	  Support for Xilinx Zynq ARM Cortex A9 Platform

arch/arm/mach-zynq/common.c

@@ -29,6 +29,8 @@
 #include <linux/memblock.h>
 #include <linux/irqchip.h>
 #include <linux/irqchip/arm-gic.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
 
 #include <asm/mach/arch.h>
 #include <asm/mach/map.h>
@@ -37,10 +39,15 @@
 #include <asm/page.h>
 #include <asm/pgtable.h>
 #include <asm/smp_scu.h>
+#include <asm/system_info.h>
 #include <asm/hardware/cache-l2x0.h>
 
 #include "common.h"
 
+#define ZYNQ_DEVCFG_MCTRL		0x80
+#define ZYNQ_DEVCFG_PS_VERSION_SHIFT	28
+#define ZYNQ_DEVCFG_PS_VERSION_MASK	0xF
+
 void __iomem *zynq_scu_base;
 
 /**
@@ -59,6 +66,38 @@ static struct platform_device zynq_cpuidle_device = {
 	.name = "cpuidle-zynq",
 };
 
+/**
+ * zynq_get_revision - Get Zynq silicon revision
+ *
+ * Return: Silicon version or -1 otherwise
+ */
+static int __init zynq_get_revision(void)
+{
+	struct device_node *np;
+	void __iomem *zynq_devcfg_base;
+	u32 revision;
+
+	np = of_find_compatible_node(NULL, NULL, "xlnx,zynq-devcfg-1.0");
+	if (!np) {
+		pr_err("%s: no devcfg node found\n", __func__);
+		return -1;
+	}
+
+	zynq_devcfg_base = of_iomap(np, 0);
+	if (!zynq_devcfg_base) {
+		pr_err("%s: Unable to map I/O memory\n", __func__);
+		return -1;
+	}
+
+	revision = readl(zynq_devcfg_base + ZYNQ_DEVCFG_MCTRL);
+	revision >>= ZYNQ_DEVCFG_PS_VERSION_SHIFT;
+	revision &= ZYNQ_DEVCFG_PS_VERSION_MASK;
+
+	iounmap(zynq_devcfg_base);
+
+	return revision;
+}
+
 /**
  * zynq_init_machine - System specific initialization, intended to be
  *		       called from board specific initialization.
@@ -66,13 +105,43 @@ static struct platform_device zynq_cpuidle_device = {
 static void __init zynq_init_machine(void)
 {
 	struct platform_device_info devinfo = { .name = "cpufreq-cpu0", };
+	struct soc_device_attribute *soc_dev_attr;
+	struct soc_device *soc_dev;
+	struct device *parent = NULL;
 
 	/*
 	 * 64KB way size, 8-way associativity, parity disabled
 	 */
 	l2x0_of_init(0x02060000, 0xF0F0FFFF);
 
-	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
+	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+	if (!soc_dev_attr)
+		goto out;
+
+	system_rev = zynq_get_revision();
+
+	soc_dev_attr->family = kasprintf(GFP_KERNEL, "Xilinx Zynq");
+	soc_dev_attr->revision = kasprintf(GFP_KERNEL, "0x%x", system_rev);
+	soc_dev_attr->soc_id = kasprintf(GFP_KERNEL, "0x%x",
+					 zynq_slcr_get_device_id());
+
+	soc_dev = soc_device_register(soc_dev_attr);
+	if (IS_ERR(soc_dev)) {
+		kfree(soc_dev_attr->family);
+		kfree(soc_dev_attr->revision);
+		kfree(soc_dev_attr->soc_id);
+		kfree(soc_dev_attr);
+		goto out;
+	}
+
+	parent = soc_device_to_device(soc_dev);
+
+out:
+	/*
+	 * Finished with the static registrations now; fill in the missing
+	 * devices
+	 */
+	of_platform_populate(NULL, of_default_bus_match_table, NULL, parent);
 
 	platform_device_register(&zynq_cpuidle_device);
 	platform_device_register_full(&devinfo);

arch/arm/mach-zynq/common.h

@@ -24,6 +24,7 @@ extern int zynq_early_slcr_init(void);
 extern void zynq_slcr_system_reset(void);
 extern void zynq_slcr_cpu_stop(int cpu);
 extern void zynq_slcr_cpu_start(int cpu);
+extern u32 zynq_slcr_get_device_id(void);
 
 #ifdef CONFIG_SMP
 extern void secondary_startup(void);

arch/arm/mach-zynq/slcr.c

@@ -26,10 +26,13 @@
 #define SLCR_PS_RST_CTRL_OFFSET		0x200 /* PS Software Reset Control */
 #define SLCR_A9_CPU_RST_CTRL_OFFSET	0x244 /* CPU Software Reset Control */
 #define SLCR_REBOOT_STATUS_OFFSET	0x258 /* PS Reboot Status */
+#define SLCR_PSS_IDCODE			0x530 /* PS IDCODE */
 
 #define SLCR_UNLOCK_MAGIC		0xDF0D
 #define SLCR_A9_CPU_CLKSTOP		0x10
 #define SLCR_A9_CPU_RST			0x1
+#define SLCR_PSS_IDCODE_DEVICE_SHIFT	12
+#define SLCR_PSS_IDCODE_DEVICE_MASK	0x1F
 
 static void __iomem *zynq_slcr_base;
 static struct regmap *zynq_slcr_regmap;
@@ -82,6 +85,22 @@ static inline int zynq_slcr_unlock(void)
 	return 0;
 }
 
+/**
+ * zynq_slcr_get_device_id - Read device code id
+ *
+ * Return:	Device code id
+ */
+u32 zynq_slcr_get_device_id(void)
+{
+	u32 val;
+
+	zynq_slcr_read(&val, SLCR_PSS_IDCODE);
+	val >>= SLCR_PSS_IDCODE_DEVICE_SHIFT;
+	val &= SLCR_PSS_IDCODE_DEVICE_MASK;
+
+	return val;
+}
+
 /**
  * zynq_slcr_system_reset - Reset the entire system.
  */