c1edfbcf4b
Introduce a generic reset MMIO driver to be used for devices with a single memory mapped reset bit required to take them out of reset. Signed-off-by: Mohith Potluri <saimohith@google.com>
112 lines
2.9 KiB
C
112 lines
2.9 KiB
C
/* Copyright (c) 2025 Google LLC.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <zephyr/device.h>
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#include <zephyr/devicetree.h>
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#include <zephyr/drivers/reset.h>
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#include <zephyr/kernel.h>
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struct reset_mmio_dev_config {
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uint32_t base;
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uint8_t num_resets;
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bool active_low;
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};
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struct reset_mmio_dev_data {
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struct k_spinlock lock;
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};
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static inline int reset_mmio_status(const struct device *dev, uint32_t id, uint8_t *status)
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{
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const struct reset_mmio_dev_config *config = dev->config;
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uint32_t value;
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if (id >= config->num_resets) {
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return -EINVAL;
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}
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value = sys_read32(config->base);
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*status = FIELD_GET(BIT(id), value);
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/* If active low, invert the logic */
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if (config->active_low) {
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*status = !(*status);
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}
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return 0;
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}
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static inline int reset_mmio_update(const struct device *dev, uint32_t id, uint8_t assert)
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{
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const struct reset_mmio_dev_config *config = dev->config;
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struct reset_mmio_dev_data *data = dev->data;
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uint32_t value;
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bool set;
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if (id >= config->num_resets) {
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return -EINVAL;
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}
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/* If active low, invert the logic */
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set = config->active_low ? !assert : assert;
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K_SPINLOCK(&data->lock) {
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value = sys_read32(config->base);
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if (set) {
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value |= BIT(id);
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} else {
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value &= ~BIT(id);
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}
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sys_write32(value, config->base);
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}
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return 0;
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}
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static int reset_mmio_line_assert(const struct device *dev, uint32_t id)
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{
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return reset_mmio_update(dev, id, 1);
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}
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static int reset_mmio_line_deassert(const struct device *dev, uint32_t id)
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{
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return reset_mmio_update(dev, id, 0);
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}
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static int reset_mmio_line_toggle(const struct device *dev, uint32_t id)
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{
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uint8_t reset_status = 0;
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int status;
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status = reset_mmio_status(dev, id, &reset_status);
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if (status) {
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return status;
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}
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return reset_mmio_update(dev, id, !reset_status);
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}
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static DEVICE_API(reset, reset_mmio_driver_api) = {
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.status = reset_mmio_status,
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.line_assert = reset_mmio_line_assert,
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.line_deassert = reset_mmio_line_deassert,
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.line_toggle = reset_mmio_line_toggle,
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};
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#define DT_DRV_COMPAT reset_mmio
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#define RESET_MMIO_INIT(n) \
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BUILD_ASSERT(DT_INST_PROP(n, num_resets) > 0 && DT_INST_PROP(n, num_resets) < 32, \
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"num-resets needs to be in [1, 31]."); \
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static const struct reset_mmio_dev_config reset_mmio_dev_config_##n = { \
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.base = DT_INST_REG_ADDR(n), \
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.num_resets = DT_INST_PROP(n, num_resets), \
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.active_low = DT_INST_PROP(n, active_low)}; \
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static struct reset_mmio_dev_data reset_mmio_dev_data_##n; \
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DEVICE_DT_INST_DEFINE(n, NULL, NULL, &reset_mmio_dev_data_##n, &reset_mmio_dev_config_##n, \
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POST_KERNEL, CONFIG_RESET_INIT_PRIORITY, &reset_mmio_driver_api);
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DT_INST_FOREACH_STATUS_OKAY(RESET_MMIO_INIT)
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