dm: Add a system reset uclass
It is common for system reset to be available at multiple levels in modern
hardware. For example, an SoC may provide a reset option, and a board may
provide its own reset for reasons of security or thoroughness. It is useful
to be able to model this hardware without hard-coding the behaviour in the
SoC or board. Also there is a distinction sometimes between resetting just
the CPU (leaving GPIO state alone) and resetting all the PMICs, just cutting
power.
To achieve this, add a simple system reset uclass. It allows multiple devices
to provide reset functionality and provides a way to walk through them,
requesting a particular reset type until is it provided.
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 64b07a3..3b7f76a 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -73,3 +73,12 @@
default 0x60
help
The I2C address of the PCA9551 LED controller.
+
+config RESET
+ bool "Enable support for reset drivers"
+ depends on DM
+ help
+ Enable reset drivers which can be used to reset the CPU or board.
+ Each driver can provide a reset method which will be called to
+ effect a reset. The uclass will try all available drivers when
+ reset_walk() is called.
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 120babc..5da5178 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -32,3 +32,4 @@
obj-$(CONFIG_FSL_IFC) += fsl_ifc.o
obj-$(CONFIG_FSL_SEC_MON) += fsl_sec_mon.o
obj-$(CONFIG_PCA9551_LED) += pca9551_led.o
+obj-$(CONFIG_RESET) += reset-uclass.o
diff --git a/drivers/misc/reset-uclass.c b/drivers/misc/reset-uclass.c
new file mode 100644
index 0000000..ba27757
--- /dev/null
+++ b/drivers/misc/reset-uclass.c
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <reset.h>
+#include <dm.h>
+#include <errno.h>
+#include <regmap.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <dm/root.h>
+#include <linux/err.h>
+
+int reset_request(struct udevice *dev, enum reset_t type)
+{
+ struct reset_ops *ops = reset_get_ops(dev);
+
+ if (!ops->request)
+ return -ENOSYS;
+
+ return ops->request(dev, type);
+}
+
+void reset_walk(enum reset_t type)
+{
+ struct udevice *dev;
+ int ret = 0;
+
+ while (ret != -EINPROGRESS && type < RESET_COUNT) {
+ for (uclass_first_device(UCLASS_RESET, &dev);
+ dev;
+ uclass_next_device(&dev)) {
+ ret = reset_request(dev, type);
+ if (ret == -EINPROGRESS)
+ break;
+ }
+ }
+
+ /* Wait for the reset to take effect */
+ mdelay(100);
+
+ /* Still no reset? Give up */
+ printf("Reset not supported on this platform\n");
+ hang();
+}
+
+/**
+ * reset_cpu() - calls reset_walk(RESET_WARM)
+ */
+void reset_cpu(ulong addr)
+{
+ reset_walk(RESET_WARM);
+}
+
+UCLASS_DRIVER(reset) = {
+ .id = UCLASS_RESET,
+ .name = "reset",
+};