Identify the SoC type and revision, and register this information with
the SoC bus, so it is available under /sys/devices/soc0/, and can be
checked where needed using soc_device_match().

In addition, on SoCs that support it, the product ID is read from a
hardware register and validated, to catch accidental use of a DTB for a
different SoC.

Example:

    Detected Renesas r8a7791 ES1.0
    ...
    # cat /sys/devices/soc0/{family,machine,soc_id,revision}
    R-Car Gen2
    Koelsch
    r8a7791
    ES1.0

Signed-off-by: Geert Uytterhoeven <[email protected]>
---
This patch does NOT add a call to

        of_platform_default_populate(NULL, NULL,
                                     soc_device_to_device(soc_dev));

Contrary to suggested by commit 74d1d82cdaaec727 ("drivers/base: add bus
for System-on-Chip devices), doing so would not only move on-SoC devices
from /sys/devices/platform/ to /sys/devices/soc0/, but also all other
board (off-SoC) devices specified in the DTB.
---
 arch/arm/mach-shmobile/Kconfig    |   1 +
 arch/arm64/Kconfig.platforms      |   1 +
 drivers/soc/renesas/Makefile      |   2 +
 drivers/soc/renesas/renesas-soc.c | 266 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 270 insertions(+)
 create mode 100644 drivers/soc/renesas/renesas-soc.c

diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig
index b5a3cbe81dd1d1f0..e41d2cbb2c825981 100644
--- a/arch/arm/mach-shmobile/Kconfig
+++ b/arch/arm/mach-shmobile/Kconfig
@@ -42,6 +42,7 @@ menuconfig ARCH_RENESAS
        select HAVE_ARM_TWD if SMP
        select NO_IOPORT_MAP
        select PINCTRL
+       select SOC_BUS
        select ZONE_DMA if ARM_LPAE
 
 if ARCH_RENESAS
diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms
index be5d824ebdba2dab..a2675afc61baba8d 100644
--- a/arch/arm64/Kconfig.platforms
+++ b/arch/arm64/Kconfig.platforms
@@ -131,6 +131,7 @@ config ARCH_RENESAS
        select PM
        select PM_GENERIC_DOMAINS
        select RENESAS_IRQC
+       select SOC_BUS
        help
          This enables support for the ARMv8 based Renesas SoCs.
 
diff --git a/drivers/soc/renesas/Makefile b/drivers/soc/renesas/Makefile
index 623039c3514cdc34..ae6ae8a11f98aba1 100644
--- a/drivers/soc/renesas/Makefile
+++ b/drivers/soc/renesas/Makefile
@@ -1,3 +1,5 @@
+obj-y                          += renesas-soc.o
+
 obj-$(CONFIG_ARCH_R8A7779)     += rcar-sysc.o r8a7779-sysc.o
 obj-$(CONFIG_ARCH_R8A7790)     += rcar-sysc.o r8a7790-sysc.o
 obj-$(CONFIG_ARCH_R8A7791)     += rcar-sysc.o r8a7791-sysc.o
diff --git a/drivers/soc/renesas/renesas-soc.c 
b/drivers/soc/renesas/renesas-soc.c
new file mode 100644
index 0000000000000000..74b72e4112b8889e
--- /dev/null
+++ b/drivers/soc/renesas/renesas-soc.c
@@ -0,0 +1,266 @@
+/*
+ * Renesas SoC Identification
+ *
+ * Copyright (C) 2014-2016 Glider bvba
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/sys_soc.h>
+
+
+struct renesas_family {
+       const char name[16];
+       u32 reg;                        /* CCCR, PVR, or PRR */
+};
+
+static const struct renesas_family fam_emev2 __initconst = {
+       .name   = "Emma Mobile EV2",
+};
+
+static const struct renesas_family fam_rmobile __initconst = {
+       .name   = "R-Mobile",
+       .reg    = 0xe600101c,           /* CCCR (Common Chip Code Register) */
+};
+
+static const struct renesas_family fam_rcar_gen1 __initconst = {
+       .name   = "R-Car Gen1",
+       .reg    = 0xff000044,           /* PRR (Product Register) */
+};
+
+static const struct renesas_family fam_rcar_gen2 __initconst = {
+       .name   = "R-Car Gen2",
+       .reg    = 0xff000044,           /* PRR (Product Register) */
+};
+
+static const struct renesas_family fam_rcar_gen3 __initconst = {
+       .name   = "R-Car Gen3",
+       .reg    = 0xfff00044,           /* PRR (Product Register) */
+};
+
+static const struct renesas_family fam_rza __initconst = {
+       .name   = "RZ/A",
+};
+
+static const struct renesas_family fam_rzg __initconst = {
+       .name   = "RZ/G",
+       .reg    = 0xff000044,           /* PRR (Product Register) */
+};
+
+static const struct renesas_family fam_shmobile __initconst = {
+       .name   = "SH-Mobile",
+       .reg    = 0xe600101c,           /* CCCR (Common Chip Code Register) */
+};
+
+
+struct renesas_soc {
+       const struct renesas_family *family;
+       u8 id;
+};
+
+static const struct renesas_soc soc_emev2 __initconst = {
+       .family = &fam_emev2,
+};
+
+static const struct renesas_soc soc_rz_a1h __initconst = {
+       .family = &fam_rza,
+};
+
+static const struct renesas_soc soc_rmobile_ape6 __initconst = {
+       .family = &fam_rmobile,
+       .id     = 0x3f,
+};
+
+static const struct renesas_soc soc_rmobile_a1 __initconst = {
+       .family = &fam_rmobile,
+       .id     = 0x40,
+};
+
+static const struct renesas_soc soc_rz_g1m __initconst = {
+       .family = &fam_rzg,
+       .id     = 0x47,
+};
+
+static const struct renesas_soc soc_rz_g1e __initconst = {
+       .family = &fam_rzg,
+       .id     = 0x4c,
+};
+
+static const struct renesas_soc soc_rcar_m1a __initconst = {
+       .family = &fam_rcar_gen1,
+};
+
+static const struct renesas_soc soc_rcar_h1 __initconst = {
+       .family = &fam_rcar_gen1,
+       .id     = 0x3b,
+};
+
+static const struct renesas_soc soc_rcar_h2 __initconst = {
+       .family = &fam_rcar_gen2,
+       .id     = 0x45,
+};
+
+static const struct renesas_soc soc_rcar_m2_w __initconst = {
+       .family = &fam_rcar_gen2,
+       .id     = 0x47,
+};
+
+static const struct renesas_soc soc_rcar_v2h __initconst = {
+       .family = &fam_rcar_gen2,
+       .id     = 0x4a,
+};
+
+static const struct renesas_soc soc_rcar_m2_n __initconst = {
+       .family = &fam_rcar_gen2,
+       .id     = 0x4b,
+};
+
+static const struct renesas_soc soc_rcar_e2 __initconst = {
+       .family = &fam_rcar_gen2,
+       .id     = 0x4c,
+};
+
+static const struct renesas_soc soc_rcar_h3 __initconst = {
+       .family = &fam_rcar_gen3,
+       .id     = 0x4f,
+};
+
+static const struct renesas_soc soc_rcar_m3_w __initconst = {
+       .family = &fam_rcar_gen3,
+       .id     = 0x52,
+};
+
+static const struct renesas_soc soc_shmobile_ag5 __initconst = {
+       .family = &fam_shmobile,
+       .id     = 0x37,
+};
+
+static const struct of_device_id renesas_socs[] __initconst = {
+#ifdef CONFIG_ARCH_EMEV2
+       { .compatible = "renesas,emev2",        .data = &soc_emev2 },
+#endif
+#ifdef CONFIG_ARCH_R7S72100
+       { .compatible = "renesas,r7s72100",     .data = &soc_rz_a1h },
+#endif
+#ifdef CONFIG_ARCH_R8A73A4
+       { .compatible = "renesas,r8a73a4",      .data = &soc_rmobile_ape6 },
+#endif
+#ifdef CONFIG_ARCH_R8A7740
+       { .compatible = "renesas,r8a7740",      .data = &soc_rmobile_a1 },
+#endif
+#ifdef CONFIG_ARCH_R8A7743
+       { .compatible = "renesas,r8a7743",      .data = &soc_rz_g1m },
+#endif
+#ifdef CONFIG_ARCH_R8A7745
+       { .compatible = "renesas,r8a7745",      .data = &soc_rz_g1e },
+#endif
+#ifdef CONFIG_ARCH_R8A7778
+       { .compatible = "renesas,r8a7778",      .data = &soc_rcar_m1a },
+#endif
+#ifdef CONFIG_ARCH_R8A7779
+       { .compatible = "renesas,r8a7779",      .data = &soc_rcar_h1 },
+#endif
+#ifdef CONFIG_ARCH_R8A7790
+       { .compatible = "renesas,r8a7790",      .data = &soc_rcar_h2 },
+#endif
+#ifdef CONFIG_ARCH_R8A7791
+       { .compatible = "renesas,r8a7791",      .data = &soc_rcar_m2_w },
+#endif
+#ifdef CONFIG_ARCH_R8A7792
+       { .compatible = "renesas,r8a7792",      .data = &soc_rcar_v2h },
+#endif
+#ifdef CONFIG_ARCH_R8A7793
+       { .compatible = "renesas,r8a7793",      .data = &soc_rcar_m2_n },
+#endif
+#ifdef CONFIG_ARCH_R8A7794
+       { .compatible = "renesas,r8a7794",      .data = &soc_rcar_e2 },
+#endif
+#ifdef CONFIG_ARCH_R8A7795
+       { .compatible = "renesas,r8a7795",      .data = &soc_rcar_h3 },
+#endif
+#ifdef CONFIG_ARCH_R8A7796
+       { .compatible = "renesas,r8a7796",      .data = &soc_rcar_m3_w },
+#endif
+#ifdef CONFIG_ARCH_SH73A0
+       { .compatible = "renesas,sh73a0",       .data = &soc_shmobile_ag5 },
+#endif
+       { /* sentinel */ }
+};
+
+static int __init renesas_soc_init(void)
+{
+       struct soc_device_attribute *soc_dev_attr;
+       const struct renesas_family *family;
+       unsigned int product, esi = 0, esf;
+       const struct of_device_id *match;
+       const struct renesas_soc *soc;
+       struct soc_device *soc_dev;
+       struct device_node *np;
+       void __iomem *mapped;
+
+       np = of_find_matching_node_and_match(NULL, renesas_socs, &match);
+       if (!np)
+               return -ENODEV;
+
+       of_node_put(np);
+       soc = match->data;
+       family = soc->family;
+
+       if (soc->id) {
+               mapped = ioremap(family->reg, 4);
+               if (!mapped)
+                       return -ENOMEM;
+
+               product = readl(mapped);
+               iounmap(mapped);
+
+               if (((product >> 8) & 0xff) != soc->id) {
+                       pr_crit("SoC mismatch (product = 0x%x)\n", product);
+                       return -ENODEV;
+               }
+
+               esi = ((product >> 4) & 0x0f) + 1;
+               esf = product & 0xf;
+       }
+
+       soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+       if (!soc_dev_attr)
+               return -ENOMEM;
+
+       np = of_find_node_by_path("/");
+       of_property_read_string(np, "model", &soc_dev_attr->machine);
+       of_node_put(np);
+
+       soc_dev_attr->family = kstrdup_const(family->name, GFP_KERNEL);
+       soc_dev_attr->soc_id = kstrdup_const(strchr(match->compatible, ',') + 1,
+                                            GFP_KERNEL);
+       if (esi > 0)
+               soc_dev_attr->revision = kasprintf(GFP_KERNEL, "ES%u.%u", esi,
+                                                  esf);
+
+       pr_info("Detected Renesas %s %s\n", soc_dev_attr->soc_id,
+               soc_dev_attr->revision ?: "");
+
+       soc_dev = soc_device_register(soc_dev_attr);
+       if (IS_ERR(soc_dev)) {
+               kfree(soc_dev_attr->revision);
+               kfree_const(soc_dev_attr->soc_id);
+               kfree_const(soc_dev_attr->family);
+               kfree(soc_dev_attr);
+               return PTR_ERR(soc_dev);
+       }
+
+       return 0;
+}
+core_initcall(renesas_soc_init);
-- 
1.9.1

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