dm: soc: Introduce soc_ti_k3 driver for TI K3 SoCs

Introduce an soc_ti_k3_driver that allows identification and selection
of SoC specific data based on the JTAG ID register for device
identification, as described for AM65x[0] and J721E[1] devices.

[0] http://www.ti.com/lit/ug/spruid7e/spruid7e.pdf
[1] http://www.ti.com/lit/ug/spruil1a/spruil1a.pdf

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>

drivers/soc/Kconfig

@@ -9,6 +9,13 @@ config SOC_DEVICE
 	  need different parameters or quirks enabled depending on the
 	  specific device variant in use.
 
+config SOC_DEVICE_TI_K3
+	depends on SOC_DEVICE
+	bool "Enable SoC Device ID driver for TI K3 SoCs"
+	help
+	  This allows Texas Instruments Keystone 3 SoCs to identify
+	  specifics about the SoC in use.
+
 source "drivers/soc/ti/Kconfig"
 
 endmenu

drivers/soc/Makefile

@@ -4,4 +4,5 @@
 
 obj-$(CONFIG_SOC_TI) += ti/
 obj-$(CONFIG_SOC_DEVICE) += soc-uclass.o
+obj-$(CONFIG_SOC_DEVICE_TI_K3) += soc_ti_k3.o
 obj-$(CONFIG_SANDBOX) += soc_sandbox.o

drivers/soc/soc_ti_k3.c

@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com/
+ *	Dave Gerlach <d-gerlach@ti.com>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <soc.h>
+
+#include <asm/io.h>
+
+#define AM65X			0xbb5a
+#define J721E			0xbb64
+
+#define REV_SR1_0		0
+#define REV_SR2_0		1
+
+#define JTAG_ID_VARIANT_SHIFT	28
+#define JTAG_ID_VARIANT_MASK	(0xf << 28)
+#define JTAG_ID_PARTNO_SHIFT	12
+#define JTAG_ID_PARTNO_MASK	(0xffff << 12)
+
+struct soc_ti_k3_platdata {
+	const char *family;
+	const char *revision;
+};
+
+static const char *get_family_string(u32 idreg)
+{
+	const char *family;
+	u32 soc;
+
+	soc = (idreg & JTAG_ID_PARTNO_MASK) >> JTAG_ID_PARTNO_SHIFT;
+
+	switch (soc) {
+	case AM65X:
+		family = "AM65X";
+		break;
+	case J721E:
+		family = "J721E";
+		break;
+	default:
+		family = "Unknown Silicon";
+	};
+
+	return family;
+}
+
+static const char *get_rev_string(u32 idreg)
+{
+	const char *revision;
+	u32 rev;
+
+	rev = (idreg & JTAG_ID_VARIANT_MASK) >> JTAG_ID_VARIANT_SHIFT;
+
+	switch (rev) {
+	case REV_SR1_0:
+		revision = "1.0";
+		break;
+	case REV_SR2_0:
+		revision = "2.0";
+		break;
+	default:
+		revision = "Unknown Revision";
+	};
+
+	return revision;
+}
+
+static int soc_ti_k3_get_family(struct udevice *dev, char *buf, int size)
+{
+	struct soc_ti_k3_platdata *plat = dev_get_platdata(dev);
+
+	snprintf(buf, size, "%s", plat->family);
+
+	return 0;
+}
+
+static int soc_ti_k3_get_revision(struct udevice *dev, char *buf, int size)
+{
+	struct soc_ti_k3_platdata *plat = dev_get_platdata(dev);
+
+	snprintf(buf, size, "SR%s", plat->revision);
+
+	return 0;
+}
+
+static const struct soc_ops soc_ti_k3_ops = {
+	.get_family = soc_ti_k3_get_family,
+	.get_revision = soc_ti_k3_get_revision,
+};
+
+int soc_ti_k3_probe(struct udevice *dev)
+{
+	struct soc_ti_k3_platdata *plat = dev_get_platdata(dev);
+	u32 idreg;
+	void *idreg_addr;
+
+	idreg_addr = dev_read_addr_ptr(dev);
+	if (!idreg_addr)
+		return -EINVAL;
+
+	idreg = readl(idreg_addr);
+
+	plat->family = get_family_string(idreg);
+	plat->revision = get_rev_string(idreg);
+
+	return 0;
+}
+
+static const struct udevice_id soc_ti_k3_ids[] = {
+	{ .compatible = "ti,am654-chipid" },
+	{ }
+};
+
+U_BOOT_DRIVER(soc_ti_k3) = {
+	.name           = "soc_ti_k3",
+	.id             = UCLASS_SOC,
+	.ops		= &soc_ti_k3_ops,
+	.of_match       = soc_ti_k3_ids,
+	.probe          = soc_ti_k3_probe,
+	.platdata_auto_alloc_size = sizeof(struct soc_ti_k3_platdata),
+};