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>

diff --git a/drivers/Kconfig b/drivers/Kconfig
index 941aa0c2612afee95afad1cbcacfc12fa640a4df..1f4088778b631b295daa78473eac4d3ef920ccf8 100644 (file)
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -2,6 +2,8 @@ menu "Device Drivers"
 
 source "drivers/core/Kconfig"
 
+source "drivers/cpu/Kconfig"
+
 source "drivers/demo/Kconfig"
 
 source "drivers/pci/Kconfig"

diff --git a/drivers/Makefile b/drivers/Makefile
index 5ef58c051e7f969c0f1c25a247a933975fa129e3..405b64b26873ce5076b56047128a4f62de565e73 100644 (file)
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_DM_DEMO) += demo/
 obj-$(CONFIG_BIOSEMU) += bios_emulator/
 obj-y += block/
 obj-$(CONFIG_BOOTCOUNT_LIMIT) += bootcount/
+obj-$(CONFIG_CPU) += cpu/
 obj-y += crypto/
 obj-$(CONFIG_FPGA) += fpga/
 obj-y += hwmon/

diff --git a/drivers/cpu/Kconfig b/drivers/cpu/Kconfig
new file mode 100644 (file)
index 0000000..0d1424d
--- /dev/null
+++ b/drivers/cpu/Kconfig
@@ -0,0 +1,8 @@
+config CPU
+       bool "Enable CPU drivers using Driver Model"
+       help
+         This allows drivers to be provided for CPUs and their type to be
+         specified in the board's device tree. For boards which support
+         multiple CPUs, then normally have to be set up in U-Boot so that
+         they can work correctly in the OS. This provides a framework for
+         finding out information about available CPUs and making changes.

diff --git a/drivers/cpu/Makefile b/drivers/cpu/Makefile
new file mode 100644 (file)
index 0000000..8710160
--- /dev/null
+++ b/drivers/cpu/Makefile
@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2015 Google, Inc
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+#
+# SPDX-License-Identifier:      GPL-2.0+
+#
+obj-$(CONFIG_CPU) += cpu-uclass.o

diff --git a/drivers/cpu/cpu-uclass.c b/drivers/cpu/cpu-uclass.c
new file mode 100644 (file)
index 0000000..ab18ee2
--- /dev/null
+++ b/drivers/cpu/cpu-uclass.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ */
+
+#include <common.h>
+#include <cpu.h>
+#include <dm.h>
+#include <dm/lists.h>
+#include <dm/root.h>
+
+int cpu_get_desc(struct udevice *dev, char *buf, int size)
+{
+       struct cpu_ops *ops = cpu_get_ops(dev);
+
+       if (!ops->get_desc)
+               return -ENOSYS;
+
+       return ops->get_desc(dev, buf, size);
+}
+
+int cpu_get_info(struct udevice *dev, struct cpu_info *info)
+{
+       struct cpu_ops *ops = cpu_get_ops(dev);
+
+       if (!ops->get_desc)
+               return -ENOSYS;
+
+       return ops->get_info(dev, info);
+}
+
+U_BOOT_DRIVER(cpu_bus) = {
+       .name   = "cpu_bus",
+       .id     = UCLASS_SIMPLE_BUS,
+       .per_child_platdata_auto_alloc_size = sizeof(struct cpu_platdata),
+};
+
+static int uclass_cpu_init(struct uclass *uc)
+{
+       struct udevice *dev;
+       int node;
+       int ret;
+
+       node = fdt_path_offset(gd->fdt_blob, "/cpus");
+       if (node < 0)
+               return 0;
+
+       ret = device_bind_driver_to_node(dm_root(), "cpu_bus", "cpus", node,
+                                        &dev);
+
+       return ret;
+}
+
+UCLASS_DRIVER(cpu) = {
+       .id             = UCLASS_CPU,
+       .name           = "cpu",
+       .flags          = DM_UC_FLAG_SEQ_ALIAS,
+       .init           = uclass_cpu_init,
+};

diff --git a/include/cpu.h b/include/cpu.h
new file mode 100644 (file)
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

diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index fddfd35f1fbefbcb736b3835b87fc32fc5e096a6..395e25a43135835821b4c72cffaea2588d9ea352 100644 (file)
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -45,6 +45,7 @@ enum uclass_id {
        UCLASS_USB_HUB,         /* USB hub */
        UCLASS_USB_DEV_GENERIC, /* USB generic device */
        UCLASS_MASS_STORAGE,    /* Mass storage device */
+       UCLASS_CPU,             /* CPU, typically part of an SoC */
 
        UCLASS_COUNT,
        UCLASS_INVALID = -1,