[PATCH 1/3] ARM: at91: use chipid device for soc detection

Ludovic Desroches
2016-03-18T07:21:03Z

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]
---
.../devicetree/bindings/arm/atmel-at91.txt | 4 ++
arch/arm/mach-at91/soc.c | 81 +++++++++++++++++-----
2 files changed, 67 insertions(+), 18 deletions(-)

diff --git a/Documentation/devicetree/bindings/arm/atmel-at91.txt b/Documentation/devicetree/bindings/arm/atmel-at91.txt
index 7fd64ec..0b1fcbf 100644
--- 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 54343ff..034d563 100644
--- 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)
+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;
+}
+
+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;
}
--
2.5.0