[U-Boot] [PATCH v2 07/20] dm: Implement a CPU uclass
Simon Glass
sjg at chromium.org
Wed Apr 29 04:25:09 CEST 2015
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 at chromium.org>
---
Changes in v2:
- Change header guard to capital letters
- Change get_info() in function comment to cpu_get_info()
drivers/Kconfig | 2 ++
drivers/Makefile | 1 +
drivers/cpu/Kconfig | 8 +++++
drivers/cpu/Makefile | 7 ++++
drivers/cpu/cpu-uclass.c | 61 +++++++++++++++++++++++++++++++++++
include/cpu.h | 84 ++++++++++++++++++++++++++++++++++++++++++++++++
include/dm/uclass-id.h | 1 +
7 files changed, 164 insertions(+)
create mode 100644 drivers/cpu/Kconfig
create mode 100644 drivers/cpu/Makefile
create mode 100644 drivers/cpu/cpu-uclass.c
create mode 100644 include/cpu.h
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 941aa0c..1f40887 100644
--- 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 5ef58c0..405b64b 100644
--- 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-$(CONFIG_FPGA) += fpga/
obj-y += hwmon/
diff --git a/drivers/cpu/Kconfig b/drivers/cpu/Kconfig
new file mode 100644
index 0000000..0d1424d
--- /dev/null
+++ b/drivers/cpu/Kconfig
@@ -0,0 +1,8 @@
+config CPU
+ bool "Enable CPU drivers using Driver Model"
+ help
+ This allows drivers to be provided for CPUs and their type to be
+ specified in the board's device tree. For boards which support
+ multiple CPUs, then normally have to be set up in U-Boot so that
+ they can work correctly in the OS. This provides a framework for
+ finding out information about available CPUs and making changes.
diff --git a/drivers/cpu/Makefile b/drivers/cpu/Makefile
new file mode 100644
index 0000000..8710160
--- /dev/null
+++ b/drivers/cpu/Makefile
@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2015 Google, Inc
+# Wolfgang Denk, DENX Software Engineering, wd at denx.de.
+#
+# SPDX-License-Identifier: GPL-2.0+
+#
+obj-$(CONFIG_CPU) += cpu-uclass.o
diff --git a/drivers/cpu/cpu-uclass.c b/drivers/cpu/cpu-uclass.c
new file mode 100644
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 at 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
index 0000000..34c60bc
--- /dev/null
+++ b/include/cpu.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2015 Google, Inc
+ * Written by Simon Glass <sjg at 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 fddfd35..395e25a 100644
--- 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,
--
2.2.0.rc0.207.ga3a616c
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