Implement SoC bus support for Vybrid

Hello,

This patchset implements SoC bus support for Freescale Vybrid platform, implementing the following
https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-devices-soc

Currently the required information is more or less read across the whole SoC, but I guess we cannot change that since these are the locations with the required information.

There seem to be three options for the revision field:
- ROM revision (see https://community.freescale.com/docs/DOC-94802)
- ANADIG revision (ANADIG_DIGIPROC, as used for the i.MX SoC's)
- OCOTP revision

Some numbers:

Colibri VF61 1.1A (2N02G)
- 0x00000013
- 0x00610000
- 0x01000000
- 0x410000c8

Colibri VF61 V1.0B (1N02G)
- 0x00000011
- 0x00610000
- 0x01000000
- 0x410000c8

Colibri VF61 V1.0A (which is actually a VF600 SoC, no L2 cache, since that was the only one we could buy back then, 1N02G printed on it)
- 0x00000011
- 0x00610000
- 0x01000000
- none...

Colibri VF50 V1.0A (1N02G)
- 0x00000011
- 0x00610000
- 0x01000000
- none...

Vybrid Tower Rev J (1N02G)
- 0x00000011
- 0x00610000
- 0x01000000
- 0x410000c8

The ROM revision differs the most, so we would like to go with the revision information from the ROM register 0x80.

Version 1 of the patchset can be found here
http://www.spinics.net/lists/devicetree/msg80257.html

The RFC version can be found here
https://lkml.org/lkml/2015/5/11/13

Changes since v1:
- Sort the headers in alphabetical order

Changes since RFC:
- Use a DT entry for the ROM area while specifying it as syscon.

Sanchayan Maity (2):
ARM: dts: vfxxx: Add OCOTP and OCROM nodes
ARM: vf610: Add SoC bus support for Vybrid

 arch/arm/boot/dts/vfxxx.dtsi   | 10 +++++
 arch/arm/mach-imx/mach-vf610.c | 85 +++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 93 insertions(+), 2 deletions(-)

2.4.1

Add a device tree node for the On-Chip One Time Programmable Controller (OCOTP) and the On-Chip ROM.

---
 arch/arm/boot/dts/vfxxx.dtsi | 10 ++++++++++
 1 file changed, 10 insertions(+)

index 2f4b04d..66c529f 100644
@@ -57,6 +57,11 @@
 		interrupt-parent = <&mscm_ir>;
 		ranges;
 
+		ocrom: ocrom {
+			compatible = "fsl,vf610-ocrom", "syscon";
+			reg = <0x00000000 0x18000>;
+		};
+
 		aips0: aips-bus at 40000000 {
 			compatible = "fsl,aips-bus", "simple-bus";
 			#address-cells = <1>;

@@ -403,6 +408,11 @@
 				status = "disabled";
 			};
 
+			ocotp: ocotp at 400a5000 {
+				compatible = "fsl,vf610-ocotp", "syscon";
+				reg = <0x400a5000 0x1000>;
+			};
+
 			snvs0: snvs at 400a7000 {
 			    compatible = "fsl,sec-v4.0-mon", "simple-bus";
 				#address-cells = <1>;

2.4.1

Implements SoC bus support to export SoC specific information. Read the unique SoC ID from the Vybrid On Chip One Time Programmable (OCOTP) controller, SoC specific information from the Miscellaneous System Control Module (MSCM), revision from the ROM revision register and expose it via the SoC bus infrastructure.

Sample Output:

root at vf:/sys/devices/soc0# cat soc_id
df63c12a2e2161d4
root at vf:/sys/devices/soc0# cat family
Freescale Vybrid VF500
root at vf:/sys/devices/soc0# cat revision
00000013
root at vf:/sys/devices/soc0# cat machine
Freescale Vybrid

---
 arch/arm/mach-imx/mach-vf610.c | 85 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 83 insertions(+), 2 deletions(-)

index 2e7c75b..b4854f1 100644
@@ -7,10 +7,90 @@
  * (at your option) any later version.
  */
 
-#include <linux/of_platform.h>
-#include <linux/irqchip.h>
 #include <asm/mach/arch.h>
 #include <asm/hardware/cache-l2x0.h>
+#include <linux/irqchip.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_platform.h>
+#include <linux/regmap.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
+
+#define OCOTP_CFG0_OFFSET      0x00000410
+#define OCOTP_CFG1_OFFSET      0x00000420
+#define MSCM_CPxCOUNT_OFFSET   0x0000002C
+#define MSCM_CPxCFG1_OFFSET    0x00000014
+#define ROM_REVISION_OFFSET    0x00000080
+
+static void __init vf610_init_machine(void)
+{
+	struct regmap *ocotp_regmap, *mscm_regmap, *rom_regmap;
+	struct soc_device_attribute *soc_dev_attr;
+	struct device *parent = NULL;
+	struct soc_device *soc_dev;
+	char soc_type[] = "xx0";
+	u32 cpxcount, cpxcfg1;
+	u32 soc_id1, soc_id2, rom_rev;
+	u64 soc_id;
+
+	ocotp_regmap = syscon_regmap_lookup_by_compatible("fsl,vf610-ocotp");
+	if (IS_ERR(ocotp_regmap)) {
+		pr_err("regmap lookup for octop failed\n");
+		goto out;
+	}
+
+	mscm_regmap = syscon_regmap_lookup_by_compatible("fsl,vf610-mscm-cpucfg");
+	if (IS_ERR(mscm_regmap)) {
+		pr_err("regmap lookup for mscm failed");
+		goto out;
+	}
+
+	rom_regmap = syscon_regmap_lookup_by_compatible("fsl,vf610-ocrom");
+	if (IS_ERR(rom_regmap)) {
+		pr_err("regmap lookup for ocrom failed");
+		goto out;
+	}
+
+	regmap_read(ocotp_regmap, OCOTP_CFG0_OFFSET, &soc_id1);
+	regmap_read(ocotp_regmap, OCOTP_CFG1_OFFSET, &soc_id2);
+
+	soc_id = (u64) soc_id1 << 32 | soc_id2;
+	add_device_randomness(&soc_id, sizeof(soc_id));
+
+	regmap_read(mscm_regmap, MSCM_CPxCOUNT_OFFSET, &cpxcount);
+	regmap_read(mscm_regmap, MSCM_CPxCFG1_OFFSET, &cpxcfg1);
+
+	soc_type[0] = cpxcount ? '6' : '5'; /* Dual Core => VF6x0 */
+	soc_type[1] = cpxcfg1 ? '1' : '0'; /* L2 Cache => VFx10 */
+
+	regmap_read(rom_regmap, ROM_REVISION_OFFSET, &rom_rev);
+
+	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+	if (!soc_dev_attr)
+		goto out;
+
+	soc_dev_attr->machine = kasprintf(GFP_KERNEL, "Freescale Vybrid");
+	soc_dev_attr->soc_id = kasprintf(GFP_KERNEL, "%016llx", soc_id);
+	soc_dev_attr->family = kasprintf(GFP_KERNEL, "Freescale Vybrid VF%s",
+								 soc_type);
+	soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%08x", rom_rev);
+
+	soc_dev = soc_device_register(soc_dev_attr);
+	if (IS_ERR(soc_dev)) {
+		kfree(soc_dev_attr->revision);
+		kfree(soc_dev_attr->family);
+		kfree(soc_dev_attr->soc_id);
+		kfree(soc_dev_attr->machine);
+		kfree(soc_dev_attr);
+		goto out;
+	}
+
+	parent = soc_device_to_device(soc_dev);
+
+out:
+	of_platform_populate(NULL, of_default_bus_match_table, NULL, parent);
+}
 
 static const char * const vf610_dt_compat[] __initconst = {
 	"fsl,vf500",

@@ -23,5 +103,6 @@ static const char * const vf610_dt_compat[] __initconst = {
 DT_MACHINE_START(VYBRID_VF610, "Freescale Vybrid VF5xx/VF6xx (Device Tree)")
 	.l2c_aux_val	= 0,
 	.l2c_aux_mask	= ~0,
+	.init_machine = vf610_init_machine,
 	.dt_compat	= vf610_dt_compat,
 MACHINE_END

2.4.1

I would prefer to see this as a driver in drivers/soc that registers to a platform device. Is there any DT node that would be a reasonable device to bind to?

Arnd

Hm, what is a viable device? Probably the most SoC specific device in the SoC? Currently, all three devices we read from do have a vf610-something compatible string, hence would be SoC specific (ocotp, ocrom and mscm-cpucfg). Probably the last is the most SoC specific...

But somehow bind to just a random device sounds wrong to me. Couldn't we add a more specific compatible string to the soc node and bind to that?

--
Stefan

mscm-cpucfg by the name sounds right to me, especially if we later want to add some exported functions or configuration to the driver.

The other two (judging by the name without knowing anything about them) seem like pure data areas that may also be shared with other drivers and are better represented as syscon or eprom devices.

Arnd

This patchset

Shawn, speaking of Ack, the current plan is to merge the Vybrid Cortex-M4 patches directly into the arm-soc tree. If you are ok with them, could I have your Ack on them (sent out a split version of them (v8) some hours ago).

--
Stefan