reset: qcom: AOSS (always on subsystem) reset controller

Add reset controller driver for Qualcomm SDM845 SoC to
control reset signals provided by AOSS for Modem, Venus
ADSP, GPU, Camera, Wireless, Display subsystem

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

1 files changed, 133 insertions, 0 deletions

diff --git a/drivers/reset/reset-qcom-aoss.c b/drivers/reset/reset-qcom-aoss.c
new file mode 100644
index 000000000000..36db96750450
--- /dev/null
+++ b/drivers/reset/reset-qcom-aoss.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/of_device.h>
+#include <dt-bindings/reset/qcom,sdm845-aoss.h>
+
+struct qcom_aoss_reset_map {
+	unsigned int reg;
+};
+
+struct qcom_aoss_desc {
+	const struct qcom_aoss_reset_map *resets;
+	size_t num_resets;
+};
+
+struct qcom_aoss_reset_data {
+	struct reset_controller_dev rcdev;
+	void __iomem *base;
+	const struct qcom_aoss_desc *desc;
+};
+
+static const struct qcom_aoss_reset_map sdm845_aoss_resets[] = {
+	[AOSS_CC_MSS_RESTART] = {0x10000},
+	[AOSS_CC_CAMSS_RESTART] = {0x11000},
+	[AOSS_CC_VENUS_RESTART] = {0x12000},
+	[AOSS_CC_GPU_RESTART] = {0x13000},
+	[AOSS_CC_DISPSS_RESTART] = {0x14000},
+	[AOSS_CC_WCSS_RESTART] = {0x20000},
+	[AOSS_CC_LPASS_RESTART] = {0x30000},
+};
+
+static const struct qcom_aoss_desc sdm845_aoss_desc = {
+	.resets = sdm845_aoss_resets,
+	.num_resets = ARRAY_SIZE(sdm845_aoss_resets),
+};
+
+static inline struct qcom_aoss_reset_data *to_qcom_aoss_reset_data(
+				struct reset_controller_dev *rcdev)
+{
+	return container_of(rcdev, struct qcom_aoss_reset_data, rcdev);
+}
+
+static int qcom_aoss_control_assert(struct reset_controller_dev *rcdev,
+				    unsigned long idx)
+{
+	struct qcom_aoss_reset_data *data = to_qcom_aoss_reset_data(rcdev);
+	const struct qcom_aoss_reset_map *map = &data->desc->resets[idx];
+
+	writel(1, data->base + map->reg);
+	/* Wait 6 32kHz sleep cycles for reset */
+	usleep_range(200, 300);
+	return 0;
+}
+
+static int qcom_aoss_control_deassert(struct reset_controller_dev *rcdev,
+				      unsigned long idx)
+{
+	struct qcom_aoss_reset_data *data = to_qcom_aoss_reset_data(rcdev);
+	const struct qcom_aoss_reset_map *map = &data->desc->resets[idx];
+
+	writel(0, data->base + map->reg);
+	/* Wait 6 32kHz sleep cycles for reset */
+	usleep_range(200, 300);
+	return 0;
+}
+
+static int qcom_aoss_control_reset(struct reset_controller_dev *rcdev,
+					unsigned long idx)
+{
+	qcom_aoss_control_assert(rcdev, idx);
+
+	return qcom_aoss_control_deassert(rcdev, idx);
+}
+
+static const struct reset_control_ops qcom_aoss_reset_ops = {
+	.reset = qcom_aoss_control_reset,
+	.assert = qcom_aoss_control_assert,
+	.deassert = qcom_aoss_control_deassert,
+};
+
+static int qcom_aoss_reset_probe(struct platform_device *pdev)
+{
+	struct qcom_aoss_reset_data *data;
+	struct device *dev = &pdev->dev;
+	const struct qcom_aoss_desc *desc;
+	struct resource *res;
+
+	desc = of_device_get_match_data(dev);
+	if (!desc)
+		return -EINVAL;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->desc = desc;
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	data->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(data->base))
+		return PTR_ERR(data->base);
+
+	data->rcdev.owner = THIS_MODULE;
+	data->rcdev.ops = &qcom_aoss_reset_ops;
+	data->rcdev.nr_resets = desc->num_resets;
+	data->rcdev.of_node = dev->of_node;
+
+	return devm_reset_controller_register(dev, &data->rcdev);
+}
+
+static const struct of_device_id qcom_aoss_reset_of_match[] = {
+	{ .compatible = "qcom,sdm845-aoss-cc", .data = &sdm845_aoss_desc },
+	{}
+};
+
+static struct platform_driver qcom_aoss_reset_driver = {
+	.probe = qcom_aoss_reset_probe,
+	.driver  = {
+		.name = "qcom_aoss_reset",
+		.of_match_table = qcom_aoss_reset_of_match,
+	},
+};
+
+builtin_platform_driver(qcom_aoss_reset_driver);
+
+MODULE_DESCRIPTION("Qualcomm AOSS Reset Driver");
+MODULE_LICENSE("GPL v2");