On 27 Apr 2018, at 14:51, Mario Six mario.six@gdsys.cc wrote:
Since there is no canonical "board device" that can be used in board files, it is difficult to use DM function for board initialization in these cases.
Hence, add a uclass that implements a simple "board device", which can hold devices not suitable anywhere else in the device tree, and is also able to read encoded information, e.g. hard-wired GPIOs on a GPIO expander, read-only memory ICs, etc. that carry information about the hardware.
A board-uclass should model a board (i.e. provide implementations for the same key abstractions that we have in place today: e.g., board_init).
This seems more like a specialised form of a misc-device.
The devices of this uclass expose methods to read generic data types (integers, strings, booleans) to encode the information provided by the hardware.
Again, this is what a misc-device is intended for… and extending the misc-device APIs (or having a convenience layer on top of its ioctl interface?) might be more appropriate.
After reviewing the below, the similarities to the misc-device are even more apparent: if you need typed access to a key-value pair, this can be easily implemented through a common ioctl with semantic sugar at the misc-uclass level.
Signed-off-by: Mario Six mario.six@gdsys.cc
v1 -> v2:
- Corrected description of dev parameter of devinfo_detect
- Added size parameter to devinfo_get_str
- Expanded uclass documentation
- Added function to get devinfo instance
- Renamed the uclass from devinfo to board
drivers/Kconfig | 2 + drivers/Makefile | 1 + drivers/board/Kconfig | 17 +++++++ drivers/board/Makefile | 9 ++++ drivers/board/board-uclass.c | 61 +++++++++++++++++++++++ include/board.h | 115 +++++++++++++++++++++++++++++++++++++++++++ include/dm/uclass-id.h | 1 + 7 files changed, 206 insertions(+) create mode 100644 drivers/board/Kconfig create mode 100644 drivers/board/Makefile create mode 100644 drivers/board/board-uclass.c create mode 100644 include/board.h
diff --git a/drivers/Kconfig b/drivers/Kconfig index c2e813f5ad..19c7c448c0 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -22,6 +22,8 @@ source "drivers/ddr/Kconfig"
source "drivers/demo/Kconfig"
+source "drivers/board/Kconfig"
source "drivers/ddr/fsl/Kconfig"
source "drivers/dfu/Kconfig" diff --git a/drivers/Makefile b/drivers/Makefile index 6846d181aa..fecf64021c 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -72,6 +72,7 @@ obj-y += block/ obj-$(CONFIG_BOOTCOUNT_LIMIT) += bootcount/ obj-$(CONFIG_CPU) += cpu/ obj-y += crypto/ +obj-y += board/ obj-y += firmware/ obj-$(CONFIG_FPGA) += fpga/ obj-y += misc/ diff --git a/drivers/board/Kconfig b/drivers/board/Kconfig new file mode 100644 index 0000000000..cc1cf27205 --- /dev/null +++ b/drivers/board/Kconfig @@ -0,0 +1,17 @@ +menuconfig BOARD
- bool "Device Information"
- help
Support methods to query hardware configurations from internalmechanisms (e.g. reading GPIO values, determining the presence ofdevices on busses, etc.). This enables the usage of U-Boot withmodular board architectures.+if BOARD
+config BOARD_GAZERBEAM
- bool "Enable device information for the Gazerbeam board"
- help
Support querying device information for the gdsys Gazerbeam board.+endif diff --git a/drivers/board/Makefile b/drivers/board/Makefile new file mode 100644 index 0000000000..397706245a --- /dev/null +++ b/drivers/board/Makefile @@ -0,0 +1,9 @@ +# +# (C) Copyright 2017 +# Mario Six, Guntermann & Drunck GmbH, mario.six@gdsys.cc +# +# SPDX-License-Identifier: GPL-2.0+ +#
+obj-$(CONFIG_BOARD) += board-uclass.o +obj-$(CONFIG_BOARD_GAZERBEAM) += gazerbeam.o diff --git a/drivers/board/board-uclass.c b/drivers/board/board-uclass.c new file mode 100644 index 0000000000..3137437245 --- /dev/null +++ b/drivers/board/board-uclass.c @@ -0,0 +1,61 @@ +/*
- (C) Copyright 2017
- Mario Six, Guntermann & Drunck GmbH, mario.six@gdsys.cc
- SPDX-License-Identifier: GPL-2.0+
- */
+#include <common.h> +#include <dm.h> +#include <board.h>
+int get_board(struct udevice **devp) +{
- return uclass_first_device_err(UCLASS_BOARD, devp);
+}
+int board_detect(struct udevice *dev) +{
- struct board_ops *ops = board_get_ops(dev);
- if (!ops->detect)
return -ENOSYS;- return ops->detect(dev);
+}
+int board_get_bool(struct udevice *dev, int id, bool *val) +{
- struct board_ops *ops = board_get_ops(dev);
- if (!ops->get_bool)
return -ENOSYS;- return ops->get_bool(dev, id, val);
+}
+int board_get_int(struct udevice *dev, int id, int *val) +{
- struct board_ops *ops = board_get_ops(dev);
- if (!ops->get_int)
return -ENOSYS;- return ops->get_int(dev, id, val);
+}
+int board_get_str(struct udevice *dev, int id, size_t size, char *val) +{
- struct board_ops *ops = board_get_ops(dev);
- if (!ops->get_str)
return -ENOSYS;- return ops->get_str(dev, id, size, val);
+}
+UCLASS_DRIVER(board) = {
- .id = UCLASS_BOARD,
- .name = "board",
- .post_bind = dm_scan_fdt_dev,
+}; diff --git a/include/board.h b/include/board.h new file mode 100644 index 0000000000..0e64a3dfce --- /dev/null +++ b/include/board.h @@ -0,0 +1,115 @@ +/*
- (C) Copyright 2017
- Mario Six, Guntermann & Drunck GmbH, mario.six@gdsys.cc
- SPDX-License-Identifier: GPL-2.0+
- */
+/**
- This uclass encapsulates hardware methods to gather information about a
- board or a specific device such as hard-wired GPIOs on GPIO expanders,
- read-only data in flash ICs, or similar.
- The interface offers functions to read the usual standard data types (bool,
- int, string) from the device, each of which is identified by a static
- numeric ID (which will usually be defined as a enum in a header file).
- If for example dev was a board device representing a read-only serial
- number flash IC, we could call
- board_detect(dev);
- board_get_int(dev, ID_SERIAL_NUMBER, &serial);
- to read the serial number from the device.
- */
+struct board_ops {
- /**
* detect() - Run the hardware info detection procedure for this* device.** @dev: The device containing the information* @return 0 if OK, -ve on error.*/- int (*detect)(struct udevice *dev);
This doesn’t make any sense, as the probe entry-point is intended to probe for a device.
- /**
* get_bool() - Read a specific bool data value that describes the* hardware setup.** @dev: The board instance to gather the data.* @id: A unique identifier for the bool value to be read.* @val: Pointer to a buffer that receives the value read.* @return 0 if OK, -ve on error.*/- int (*get_bool)(struct udevice *dev, int id, bool *val);
- /**
* get_int() - Read a specific int data value that describes the* hardware setup.** @dev: The board instance to gather the data.* @id: A unique identifier for the int value to be read.* @val: Pointer to a buffer that receives the value read.* @return 0 if OK, -ve on error.*/- int (*get_int)(struct udevice *dev, int id, int *val);
- /**
* get_str() - Read a specific string data value that describes the* hardware setup.** @dev: The board instance to gather the data.* @id: A unique identifier for the string value to be read.* @size: The size of the buffer to receive the string data.* @val: Pointer to a buffer that receives the value read.* @return 0 if OK, -ve on error.*/- int (*get_str)(struct udevice *dev, int id, size_t size, char *val);
These could all be handled as ioctl()-calls to a misc-device by defining a common protocol and convenience layer.
+};
+#define board_get_ops(dev) ((struct board_ops *)(dev)->driver->ops)
+/**
- board_detect() - Run the hardware info detection procedure for this device.
- @dev: The device containing the information
- @return 0 if OK, -ve on error.
- */
+int board_detect(struct udevice *dev);
+/**
- board_get_bool() - Read a specific bool data value that describes the
hardware setup.
- @dev: The board instance to gather the data.
- @id: A unique identifier for the bool value to be read.
- @val: Pointer to a buffer that receives the value read.
- @return 0 if OK, -ve on error.
- */
+int board_get_bool(struct udevice *dev, int id, bool *val);
+/**
- board_get_int() - Read a specific int data value that describes the
hardware setup.
- @dev: The board instance to gather the data.
- @id: A unique identifier for the int value to be read.
- @val: Pointer to a buffer that receives the value read.
- @return 0 if OK, -ve on error.
- */
+int board_get_int(struct udevice *dev, int id, int *val);
+/**
- board_get_str() - Read a specific string data value that describes the
hardware setup.
- @dev: The board instance to gather the data.
- @id: A unique identifier for the string value to be read.
- @size: The size of the buffer to receive the string data.
- @val: Pointer to a buffer that receives the value read.
- @return 0 if OK, -ve on error.
- */
+int board_get_str(struct udevice *dev, int id, size_t size, char *val);
+int get_board(struct udevice **devp); diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h index d28fb3e23f..97327194b4 100644 --- a/include/dm/uclass-id.h +++ b/include/dm/uclass-id.h @@ -30,6 +30,7 @@ enum uclass_id { UCLASS_ADC, /* Analog-to-digital converter */ UCLASS_AHCI, /* SATA disk controller */ UCLASS_BLK, /* Block device */
- UCLASS_BOARD, /* Device information from hardware */ UCLASS_CLK, /* Clock source, e.g. used by peripherals */ UCLASS_CPU, /* CPU, typically part of an SoC */ UCLASS_CROS_EC, /* Chrome OS EC */
-- 2.16.1