[PATCH v3 12/29] dm: core: Add basic ACPI support

Simon Glass
2020-03-30T23:12:48Z

ACPI (Advanced Configuration and Power Interface) is a standard for
specifying information about a platform. It is a little like device
tree but the bindings are part of the specification and it supports an
interpreted bytecode language.

Driver model does not use ACPI for U-Boot's configuration, but it is
convenient to have it support generation of ACPI tables for passing to
Linux, etc.

As a starting point, add an optional set of ACPI operations to each
device. Initially only a single operation is available, to obtain the
ACPI name for the device. More operations are added later.

Enable ACPI for sandbox to ensure build coverage and so that we can add
tests.

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

Changes in v3:
- Compute ACPI_NAME_MAX from ACPI_NAME_LEN
- Drop 'Intel' from 'Intel ACPI'
- Rename acpi_return_name() to acpi_copy_name()
- Reword commit message to drop the bit about ACPI being complicated
- Use strncpy() instead of strcpy() in acpi_copy_name()

Changes in v2:
- Move LOGC_ACPI definition to this patch

drivers/core/Kconfig | 9 ++++++
drivers/core/Makefile | 1 +
drivers/core/acpi.c | 33 +++++++++++++++++++
include/dm/acpi.h | 73 +++++++++++++++++++++++++++++++++++++++++++
include/dm/device.h | 5 +++
include/log.h | 2 ++
6 files changed, 123 insertions(+)
create mode 100644 drivers/core/acpi.c
create mode 100644 include/dm/acpi.h

diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig
index 3b95b5387b9..a3b03993423 100644
--- a/drivers/core/Kconfig
+++ b/drivers/core/Kconfig
@@ -261,4 +261,13 @@ config DM_DEV_READ_INLINE
bool
default y if !OF_LIVE

+config ACPIGEN
+ bool "Support ACPI table generation in driver model"
+ default y if SANDBOX || GENERATE_ACPI_TABLE
+ help
+ This option enables generation of ACPI tables using driver-model
+ devices. It adds a new operation struct to each driver, to support
+ things like generating device-specific tables and returning the ACPI
+ name of a device.
+
endmenu
diff --git a/drivers/core/Makefile b/drivers/core/Makefile
index bce7467da1d..c707026a3a0 100644
--- a/drivers/core/Makefile
+++ b/drivers/core/Makefile
@@ -3,6 +3,7 @@
# Copyright (c) 2013 Google, Inc

obj-y += device.o fdtaddr.o lists.o root.o uclass.o util.o
+obj-$(CONFIG_$(SPL_TPL_)ACPIGEN) += acpi.o
obj-$(CONFIG_DEVRES) += devres.o
obj-$(CONFIG_$(SPL_)DM_DEVICE_REMOVE) += device-remove.o
obj-$(CONFIG_$(SPL_)SIMPLE_BUS) += simple-bus.o
diff --git a/drivers/core/acpi.c b/drivers/core/acpi.c
new file mode 100644
index 00000000000..0e64c21bf5b
--- /dev/null
+++ b/drivers/core/acpi.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Core driver model support for ACPI table generation
+ *
+ * Copyright 2019 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#define LOG_CATEOGRY LOGC_ACPI
+
+#include <common.h>
+#include <dm.h>
+#include <dm/acpi.h>
+#include <dm/root.h>
+
+int acpi_copy_name(char *out_name, const char *name)
+{
+ strncpy(out_name, name, ACPI_NAME_MAX);
+ out_name[ACPI_NAME_LEN] = '\0';
+
+ return 0;
+}
+
+int acpi_get_name(const struct udevice *dev, char *out_name)
+{
+ struct acpi_ops *aops;
+
+ aops = device_get_acpi_ops(dev);
+ if (aops && aops->get_name)
+ return aops->get_name(dev, out_name);
+
+ return -ENOSYS;
+}
diff --git a/include/dm/acpi.h b/include/dm/acpi.h
new file mode 100644
index 00000000000..c13d0c8448a
--- /dev/null
+++ b/include/dm/acpi.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Core ACPI (Advanced Configuration and Power Interface) support
+ *
+ * Copyright 2019 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#ifndef __DM_ACPI_H__
+#define __DM_ACPI_H__
+
+/* Allow operations to be optional for ACPI */
+#if CONFIG_IS_ENABLED(ACPIGEN)
+#define acpi_ops_ptr(_ptr) .acpi_ops = _ptr,
+#else
+#define acpi_ops_ptr(_ptr)
+#endif
+
+/* Length of an ACPI name string, excluding nul terminator */
+#define ACPI_NAME_LEN 4
+
+/* Length of an ACPI name string including nul terminator */
+#define ACPI_NAME_MAX (ACPI_NAME_LEN + 1)
+
+/**
+ * struct acpi_ops - ACPI operations supported by driver model
+ */
+struct acpi_ops {
+ /**
+ * get_name() - Obtain the ACPI name of a device
+ *
+ * @dev: Device to check
+ * @out_name: Place to put the name, must hold at least ACPI_NAME_MAX
+ * bytes
+ * @return 0 if OK, -ENOENT if no name is available, other -ve value on
+ * other error
+ */
+ int (*get_name)(const struct udevice *dev, char *out_name);
+};
+
+#define device_get_acpi_ops(dev) ((dev)->driver->acpi_ops)
+
+/**
+ * acpi_get_name() - Obtain the ACPI name of a device
+ *
+ * @dev: Device to check
+ * @out_name: Place to put the name, must hold at least ACPI_NAME_MAX
+ * bytes
+ * @return 0 if OK, -ENOENT if no name is available, other -ve value on
+ * other error
+ */
+int acpi_get_name(const struct udevice *dev, char *out_name);
+
+/**
+ * acpi_copy_name() - Copy an ACPI name to an output buffer
+ *
+ * This convenience function can be used to return a literal string as a name
+ * in functions that implement the get_name() method.
+ *
+ * For example:
+ *
+ * static int mydev_get_name(const struct udevice *dev, char *out_name)
+ * {
+ * return acpi_copy_name(out_name, "WIBB");
+ * }
+ *
+ * @out_name: Place to put the name
+ * @name: Name to copy
+ * @return 0 (always)
+ */
+int acpi_copy_name(char *out_name, const char *name);
+
+#endif
diff --git a/include/dm/device.h b/include/dm/device.h
index a56164b19bb..35e19d87005 100644
--- a/include/dm/device.h
+++ b/include/dm/device.h
@@ -245,6 +245,8 @@ struct udevice_id {
* pointers defined by the driver, to implement driver functions required by
* the uclass.
* @flags: driver flags - see DM_FLAGS_...
+ * @acpi_ops: Advanced Configuration and Power Interface (ACPI) operations,
+ * allowing the device to add things to the ACPI tables passed to Linux
*/
struct driver {
char *name;
@@ -264,6 +266,9 @@ struct driver {
int per_child_platdata_auto_alloc_size;
const void *ops; /* driver-specific operations */
uint32_t flags;
+#if CONFIG_IS_ENABLED(ACPIGEN)
+ struct acpi_ops *acpi_ops;
+#endif
};

/* Declare a new U-Boot driver */
diff --git a/include/log.h b/include/log.h
index 62fb8afbd0e..fbcbd42fb4b 100644
--- a/include/log.h
+++ b/include/log.h
@@ -51,6 +51,8 @@ enum log_category_t {
LOGC_SANDBOX, /* Related to the sandbox board */
LOGC_BLOBLIST, /* Bloblist */
LOGC_DEVRES, /* Device resources (devres_... functions) */
+ /* Advanced Configuration and Power Interface (ACPI) */
+ LOGC_ACPI,

LOGC_COUNT, /* Number of log categories */
LOGC_END, /* Sentinel value for a list of log categories */
--
2.26.0.rc2.310.g2932bb562d-goog