ARM: at91: add soc detection infrastructure

Add new structures and functions to handle AT91 SoC detection.

[alexandre.belloni@free-electrons.com: reworked DBGU detection]
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

4 files changed, 134 insertions, 1 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index e7ce6612bc42..f6c5b05e8de8 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -363,6 +363,7 @@ config ARCH_AT91
         select IRQ_DOMAIN
         select PINCTRL
         select PINCTRL_AT91
+        select SOC_BUS
         select USE_OF
         help
           This enables support for systems based on Atmel
diff --git a/arch/arm/mach-at91/Makefile b/arch/arm/mach-at91/Makefile
index 7df8c854f80f..709f059602b9 100644
--- a/arch/arm/mach-at91/Makefile
+++ b/arch/arm/mach-at91/Makefile
@@ -2,7 +2,7 @@
 # Makefile for the linux kernel.
 #
 
-obj-y           := setup.o
+obj-y           := setup.o soc.o
 
 obj-$(CONFIG_SOC_AT91SAM9)      += sam9_smc.o
 
diff --git a/arch/arm/mach-at91/soc.c b/arch/arm/mach-at91/soc.c
new file mode 100644
index 000000000000..54343ffa3e53
--- /dev/null
+++ b/arch/arm/mach-at91/soc.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2015 Atmel
+ *
+ * Alexandre Belloni <alexandre.belloni@free-electrons.com
+ * Boris Brezillon <boris.brezillon@free-electrons.com
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ */
+
+#define pr_fmt(fmt)     "AT91: " fmt
+
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
+
+#include "soc.h"
+
+#define AT91_DBGU_CIDR                  0x40
+#define AT91_DBGU_CIDR_VERSION(x)       ((x) & 0x1f)
+#define AT91_DBGU_CIDR_EXT              BIT(31)
+#define AT91_DBGU_CIDR_MATCH_MASK       0x7fffffe0
+#define AT91_DBGU_EXID                  0x44
+
+struct soc_device * __init at91_soc_init(const struct at91_soc *socs)
+{
+        struct soc_device_attribute *soc_dev_attr;
+        const struct at91_soc *soc;
+        struct soc_device *soc_dev;
+        struct device_node *np;
+        void __iomem *regs;
+        u32 cidr, exid;
+
+        np = of_find_compatible_node(NULL, NULL, "atmel,at91rm9200-dbgu");
+        if (!np)
+                np = of_find_compatible_node(NULL, NULL,
+                                             "atmel,at91sam9260-dbgu");
+
+        if (!np) {
+                pr_warn("Could not find DBGU node");
+                return NULL;
+        }
+
+        regs = of_iomap(np, 0);
+        of_node_put(np);
+
+        if (!regs) {
+                pr_warn("Could not map DBGU iomem range");
+                return NULL;
+        }
+
+        cidr = readl(regs + AT91_DBGU_CIDR);
+        exid = readl(regs + AT91_DBGU_EXID);
+
+        iounmap(regs);
+
+        for (soc = socs; soc->name; soc++) {
+                if (soc->cidr_match != (cidr & AT91_DBGU_CIDR_MATCH_MASK))
+                        continue;
+
+                if (!(cidr & AT91_DBGU_CIDR_EXT) || soc->exid_match == exid)
+                        break;
+        }
+
+        if (!soc->name) {
+                pr_warn("Could not find matching SoC description\n");
+                return NULL;
+        }
+
+        soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+        if (!soc_dev_attr)
+                return NULL;
+
+        soc_dev_attr->family = soc->family;
+        soc_dev_attr->soc_id = soc->name;
+        soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%X",
+                                           AT91_DBGU_CIDR_VERSION(cidr));
+        soc_dev = soc_device_register(soc_dev_attr);
+        if (IS_ERR(soc_dev)) {
+                kfree(soc_dev_attr->revision);
+                kfree(soc_dev_attr);
+                pr_warn("Could not register SoC device\n");
+                return NULL;
+        }
+
+        if (soc->family)
+                pr_info("Detected SoC family: %s\n", soc->family);
+        pr_info("Detected SoC: %s, revision %X\n", soc->name,
+                AT91_DBGU_CIDR_VERSION(cidr));
+
+        return soc_dev;
+}
diff --git a/arch/arm/mach-at91/soc.h b/arch/arm/mach-at91/soc.h
new file mode 100644
index 000000000000..9678a3b2d282
--- /dev/null
+++ b/arch/arm/mach-at91/soc.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2015 Atmel
+ *
+ * Boris Brezillon <boris.brezillon@free-electrons.com
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ */
+
+#ifndef __AT91_SOC_H
+#define __AT91_SOC_H
+
+#include <linux/sys_soc.h>
+
+struct at91_soc {
+        u32 cidr_match;
+        u32 exid_match;
+        const char *name;
+        const char *family;
+};
+
+#define AT91_SOC(__cidr, __exid, __name, __family)              \
+        {                                                       \
+                .cidr_match = (__cidr),                         \
+                .exid_match = (__exid),                         \
+                .name = (__name),                               \
+                .family = (__family),                           \
+        }
+
+struct soc_device * __init
+at91_soc_init(const struct at91_soc *socs);
+
+#endif /* __AT91_SOC_H */