diff options
author | Simon Glass <sjg@chromium.org> | 2015-06-23 21:39:13 (GMT) |
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committer | Simon Glass <sjg@chromium.org> | 2015-07-21 23:39:29 (GMT) |
commit | f9917454d55caf3dafa41b27d8d8274716433a4c (patch) | |
tree | 81f7c0e4cb2a9c3e04eab94ef17da21f2de1192f /drivers/misc/reset-uclass.c | |
parent | 92a655c326b22de58dcd5371ca1a62fdc57f8e04 (diff) | |
download | u-boot-fsl-qoriq-f9917454d55caf3dafa41b27d8d8274716433a4c.tar.xz |
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>
Diffstat (limited to 'drivers/misc/reset-uclass.c')
-rw-r--r-- | drivers/misc/reset-uclass.c | 62 |
1 files changed, 62 insertions, 0 deletions
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", +}; |