dm: Implement a CPU uclass

It is useful to be able to keep track of the available CPUs in a multi-CPU
system. This uclass is mostly intended for use with SMP systems.

The uclass provides methods for getting basic information about each CPU.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 84 insertions, 0 deletions

diff --git a/include/cpu.h b/include/cpu.h
new file mode 100644
index 0000000..34c60bc
--- /dev/null
+++ b/include/cpu.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __CPU_H
+#define __CPU_H
+
+/**
+ * struct cpu_platdata - platform data for a CPU
+ *
+ * This can be accessed with dev_get_parent_platdata() for any UCLASS_CPU
+ * device.
+ *
+ * @cpu_id:	Platform-specific way of identifying the CPU.
+ */
+struct cpu_platdata {
+	int cpu_id;
+};
+
+/* CPU features - mostly just a placeholder for now */
+enum {
+	CPU_FEAT_L1_CACHE	= 0,	/* Supports level 1 cache */
+	CPU_FEAT_MMU		= 1,	/* Supports virtual memory */
+
+	CPU_FEAT_COUNT,
+};
+
+/**
+ * struct cpu_info - Information about a CPU
+ *
+ * @cpu_freq:	Current CPU frequency in Hz
+ * @features:	Flags for supported CPU features
+ */
+struct cpu_info {
+	ulong cpu_freq;
+	ulong features;
+};
+
+struct cpu_ops {
+	/**
+	 * get_desc() - Get a description string for a CPU
+	 *
+	 * @dev:	Device to check (UCLASS_CPU)
+	 * @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_desc)(struct udevice *dev, char *buf, int size);
+
+	/**
+	 * get_info() - Get information about a CPU
+	 *
+	 * @dev:	Device to check (UCLASS_CPU)
+	 * @info:	Returns CPU info
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*get_info)(struct udevice *dev, struct cpu_info *info);
+};
+
+#define cpu_get_ops(dev)        ((struct cpu_ops *)(dev)->driver->ops)
+
+/**
+ * cpu_get_desc() - Get a description string for a CPU
+ *
+ * @dev:	Device to check (UCLASS_CPU)
+ * @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 cpu_get_desc(struct udevice *dev, char *buf, int size);
+
+/**
+ * cpu_get_info() - Get information about a CPU
+ *
+ * @dev:	Device to check (UCLASS_CPU)
+ * @info:	Returns CPU info
+ * @return 0 if OK, -ve on error
+ */
+int cpu_get_info(struct udevice *dev, struct cpu_info *info);
+
+#endif