dm: soc: Introduce UCLASS_SOC for SOC ID and attribute matching

Introduce UCLASS_SOC to be used for SOC identification and attribute
matching based on the SoC ID info. This allows drivers to be provided
for SoCs to retrieve SoC identifying information and also for matching
device attributes for selecting SoC specific data.

This is useful for other device drivers that may need different
parameters or quirks enabled depending on the specific device variant in
use.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>

drivers/soc/Kconfig

@@ -1,5 +1,14 @@
 menu "SOC (System On Chip) specific Drivers"
 
+config SOC_DEVICE
+	bool "Enable SoC Device ID drivers using Driver Model"
+	help
+	  This allows drivers to be provided for SoCs to help in identifying
+	  the SoC in use and matching SoC attributes for selecting SoC
+	  specific data. This is useful for other device drivers that may
+	  need different parameters or quirks enabled depending on the
+	  specific device variant in use.
+
 source "drivers/soc/ti/Kconfig"
 
 endmenu

drivers/soc/Makefile

@@ -3,3 +3,4 @@
 # Makefile for the U-Boot SOC specific device drivers.
 
 obj-$(CONFIG_SOC_TI) += ti/
+obj-$(CONFIG_SOC_DEVICE) += soc-uclass.o

drivers/soc/soc-uclass.c

@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2020 - Texas Instruments Incorporated - http://www.ti.com/
+ *	Dave Gerlach <d-gerlach@ti.com>
+ */
+
+#include <common.h>
+#include <soc.h>
+#include <dm.h>
+#include <errno.h>
+#include <dm/lists.h>
+#include <dm/root.h>
+
+int soc_get(struct udevice **devp)
+{
+	return uclass_first_device_err(UCLASS_SOC, devp);
+}
+
+int soc_get_machine(struct udevice *dev, char *buf, int size)
+{
+	struct soc_ops *ops = soc_get_ops(dev);
+
+	if (!ops->get_machine)
+		return -ENOSYS;
+
+	return ops->get_machine(dev, buf, size);
+}
+
+int soc_get_family(struct udevice *dev, char *buf, int size)
+{
+	struct soc_ops *ops = soc_get_ops(dev);
+
+	if (!ops->get_family)
+		return -ENOSYS;
+
+	return ops->get_family(dev, buf, size);
+}
+
+int soc_get_revision(struct udevice *dev, char *buf, int size)
+{
+	struct soc_ops *ops = soc_get_ops(dev);
+
+	if (!ops->get_revision)
+		return -ENOSYS;
+
+	return ops->get_revision(dev, buf, size);
+}
+
+const struct soc_attr *
+soc_device_match(const struct soc_attr *matches)
+{
+	bool match;
+	struct udevice *soc;
+	char str[SOC_MAX_STR_SIZE];
+
+	if (!matches)
+		return NULL;
+
+	if (soc_get(&soc))
+		return NULL;
+
+	while (1) {
+		if (!(matches->machine || matches->family ||
+		      matches->revision))
+			break;
+
+		match = true;
+
+		if (matches->machine) {
+			if (!soc_get_machine(soc, str, SOC_MAX_STR_SIZE)) {
+				if (strcmp(matches->machine, str))
+					match = false;
+			}
+		}
+
+		if (matches->family) {
+			if (!soc_get_family(soc, str, SOC_MAX_STR_SIZE)) {
+				if (strcmp(matches->family, str))
+					match = false;
+			}
+		}
+
+		if (matches->revision) {
+			if (!soc_get_revision(soc, str, SOC_MAX_STR_SIZE)) {
+				if (strcmp(matches->revision, str))
+					match = false;
+			}
+		}
+
+		if (match)
+			return matches;
+
+		matches++;
+	}
+
+	return NULL;
+}
+
+UCLASS_DRIVER(soc) = {
+	.id		= UCLASS_SOC,
+	.name		= "soc",
+};

include/dm/uclass-id.h

@@ -97,6 +97,7 @@ enum uclass_id {
 	UCLASS_SERIAL,		/* Serial UART */
 	UCLASS_SIMPLE_BUS,	/* Bus with child devices */
 	UCLASS_SMEM,		/* Shared memory interface */
+	UCLASS_SOC,		/* SOC Device */
 	UCLASS_SOUND,		/* Playing simple sounds */
 	UCLASS_SPI,		/* SPI bus */
 	UCLASS_SPI_FLASH,	/* SPI flash */

include/soc.h

@@ -0,0 +1,145 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * (C) Copyright 2020 - Texas Instruments Incorporated - http://www.ti.com/
+ *	Dave Gerlach <d-gerlach@ti.com>
+ */
+
+#ifndef __SOC_H
+#define __SOC_H
+
+#define SOC_MAX_STR_SIZE	128
+
+/**
+ * struct soc_attr - Contains SoC identify information to be used in
+ *		     SoC matching. An array of these structs
+ *		     representing different SoCs can be passed to
+ *		     soc_device_match and the struct matching the SoC
+ *		     in use will be returned.
+ *
+ * @family   - Name of SoC family that can include multiple related SoC
+ *	       variants. Example: am33
+ * @machine  - Name of a specific SoC. Example: am3352
+ * @revision - Name of a specific SoC revision. Example: SR1.1
+ * @data     - A pointer to user data for the SoC variant
+ */
+struct soc_attr {
+	const char *family;
+	const char *machine;
+	const char *revision;
+	const void *data;
+};
+
+struct soc_ops {
+	/**
+	 * get_machine() - Get machine name of an SOC
+	 *
+	 * @dev:	Device to check (UCLASS_SOC)
+	 * @buf:	Buffer to place string
+	 * @size:	Size of string space
+	 * @return 0 if OK, -ENOSPC if buffer is too small, other -ve on error
+	 */
+	int (*get_machine)(struct udevice *dev, char *buf, int size);
+
+	/**
+	 * get_revision() - Get revision name of a SOC
+	 *
+	 * @dev:	Device to check (UCLASS_SOC)
+	 * @buf:	Buffer to place string
+	 * @size:	Size of string space
+	 * @return 0 if OK, -ENOSPC if buffer is too small, other -ve on error
+	 */
+	int (*get_revision)(struct udevice *dev, char *buf, int size);
+
+	/**
+	 * get_family() - Get family name of an SOC
+	 *
+	 * @dev:	Device to check (UCLASS_SOC)
+	 * @buf:	Buffer to place string
+	 * @size:	Size of string space
+	 * @return 0 if OK, -ENOSPC if buffer is too small, other -ve on error
+	 */
+	int (*get_family)(struct udevice *dev, char *buf, int size);
+};
+
+#define soc_get_ops(dev)        ((struct soc_ops *)(dev)->driver->ops)
+
+#ifdef CONFIG_SOC_DEVICE
+/**
+ * soc_get() - Return the soc device for the soc in use.
+ * @devp: Pointer to structure to receive the soc device.
+ *
+ * Since there can only be at most one SOC instance, the API can supply a
+ * function that returns the unique device.
+ *
+ * Return: 0 if OK, -ve on error.
+ */
+int soc_get(struct udevice **devp);
+
+/**
+ * soc_get_machine() - Get machine name of an SOC
+ * @dev:	Device to check (UCLASS_SOC)
+ * @buf:	Buffer to place string
+ * @size:	Size of string space
+ *
+ * Return: 0 if OK, -ENOSPC if buffer is too small, other -ve on error
+ */
+int soc_get_machine(struct udevice *dev, char *buf, int size);
+
+/**
+ * soc_get_revision() - Get revision name of an SOC
+ * @dev:	Device to check (UCLASS_SOC)
+ * @buf:	Buffer to place string
+ * @size:	Size of string space
+ *
+ * Return: 0 if OK, -ENOSPC if buffer is too small, other -ve on error
+ */
+int soc_get_revision(struct udevice *dev, char *buf, int size);
+
+/**
+ * soc_get_family() - Get family name of an SOC
+ * @dev:	Device to check (UCLASS_SOC)
+ * @buf:	Buffer to place string
+ * @size:	Size of string space
+ *
+ * Return: 0 if OK, -ENOSPC if buffer is too small, other -ve on error
+ */
+int soc_get_family(struct udevice *dev, char *buf, int size);
+
+/**
+ * soc_device_match() - Return match from an array of soc_attr
+ * @matches:	Array with any combination of family, revision or machine set
+ *
+ * Return: Pointer to struct from matches array with set attributes matching
+ *	   those provided by the soc device, or NULL if no match found.
+ */
+const struct soc_attr *
+soc_device_match(const struct soc_attr *matches);
+
+#else
+static inline int soc_get(struct udevice **devp)
+{
+	return -ENOSYS;
+}
+
+static inline int soc_get_machine(struct udevice *dev, char *buf, int size)
+{
+	return -ENOSYS;
+}
+
+static inline int soc_get_revision(struct udevice *dev, char *buf, int size)
+{
+	return -ENOSYS;
+}
+
+static inline int soc_get_family(struct udevice *dev, char *buf, int size)
+{
+	return -ENOSYS;
+}
+
+static inline const struct soc_attr *
+soc_device_match(const struct soc_attr *matches)
+{
+	return NULL;
+}
+#endif
+#endif /* _SOC_H */