ARM: at91: use chipid device for soc detection

So far, the CIDR and EXID registers were in the DBGU interface. This device
has disappeared with the SAMA5D2 family. These registers are exposed
through a new device called chipid.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
[nicolas.ferre@atmel.com: remove useless warnings]
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Rob Herring <robh@kernel.org>
[arnd@arndb.de: suggest to use static functions to reduce scope]
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

diff --git a/Documentation/devicetree/bindings/arm/atmel-at91.txt b/Documentation/devicetree/bindings/arm/atmel-at91.txt
index 7fd64ec9ee1d5dcf78f1c1ff241a7b39f31da4f6..0b1fcbfe2299c3c350b0c8e1a9a76ce113969d0d 100644 (file)
--- a/Documentation/devicetree/bindings/arm/atmel-at91.txt
+++ b/Documentation/devicetree/bindings/arm/atmel-at91.txt
@@ -41,6 +41,10 @@ compatible: must be one of:
        - "atmel,sama5d43"
        - "atmel,sama5d44"
 
+Chipid required properties:
+- compatible: Should be "atmel,sama5d2-chipid"
+- reg : Should contain registers location and length
+
 PIT Timer required properties:
 - compatible: Should be "atmel,at91sam9260-pit"
 - reg: Should contain registers location and length

diff --git a/arch/arm/mach-at91/soc.c b/arch/arm/mach-at91/soc.c
index 54343ffa3e53352ba142c7ed1894f00f37193bc3..c6fda75ddb8970a320a9055d56b1eee45178c49f 100644 (file)
--- a/arch/arm/mach-at91/soc.c
+++ b/arch/arm/mach-at91/soc.c
@@ -22,48 +22,93 @@
 #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
+#define AT91_CHIPID_CIDR               0x00
+#define AT91_CHIPID_EXID               0x04
+#define AT91_CIDR_VERSION(x)           ((x) & 0x1f)
+#define AT91_CIDR_EXT                  BIT(31)
+#define AT91_CIDR_MATCH_MASK           0x7fffffe0
 
-struct soc_device * __init at91_soc_init(const struct at91_soc *socs)
+static int __init at91_get_cidr_exid_from_dbgu(u32 *cidr, u32 *exid)
 {
-       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)
+               return -ENODEV;
 
-       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 -ENXIO;
        }
 
+       *cidr = readl(regs + AT91_DBGU_CIDR);
+       *exid = readl(regs + AT91_DBGU_EXID);
+
+       iounmap(regs);
+
+       return 0;
+}
+
+static int __init at91_get_cidr_exid_from_chipid(u32 *cidr, u32 *exid)
+{
+       struct device_node *np;
+       void __iomem *regs;
+
+       np = of_find_compatible_node(NULL, NULL, "atmel,sama5d2-chipid");
+       if (!np)
+               return -ENODEV;
+
        regs = of_iomap(np, 0);
        of_node_put(np);
 
        if (!regs) {
                pr_warn("Could not map DBGU iomem range");
-               return NULL;
+               return -ENXIO;
        }
 
-       cidr = readl(regs + AT91_DBGU_CIDR);
-       exid = readl(regs + AT91_DBGU_EXID);
+       *cidr = readl(regs + AT91_CHIPID_CIDR);
+       *exid = readl(regs + AT91_CHIPID_EXID);
 
        iounmap(regs);
 
+       return 0;
+}
+
+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;
+       u32 cidr, exid;
+       int ret;
+
+       /*
+        * With SAMA5D2 and later SoCs, CIDR and EXID registers are no more
+        * in the dbgu device but in the chipid device whose purpose is only
+        * to expose these two registers.
+        */
+       ret = at91_get_cidr_exid_from_dbgu(&cidr, &exid);
+       if (ret)
+               ret = at91_get_cidr_exid_from_chipid(&cidr, &exid);
+       if (ret) {
+               if (ret == -ENODEV)
+                       pr_warn("Could not find identification node");
+               return NULL;
+       }
+
        for (soc = socs; soc->name; soc++) {
-               if (soc->cidr_match != (cidr & AT91_DBGU_CIDR_MATCH_MASK))
+               if (soc->cidr_match != (cidr & AT91_CIDR_MATCH_MASK))
                        continue;
 
-               if (!(cidr & AT91_DBGU_CIDR_EXT) || soc->exid_match == exid)
+               if (!(cidr & AT91_CIDR_EXT) || soc->exid_match == exid)
                        break;
        }
 
@@ -79,7 +124,7 @@ struct soc_device * __init at91_soc_init(const struct at91_soc *socs)
        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));
+                                          AT91_CIDR_VERSION(cidr));
        soc_dev = soc_device_register(soc_dev_attr);
        if (IS_ERR(soc_dev)) {
                kfree(soc_dev_attr->revision);
@@ -91,7 +136,7 @@ struct soc_device * __init at91_soc_init(const struct at91_soc *socs)
        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));
+               AT91_CIDR_VERSION(cidr));
 
        return soc_dev;
 }