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authorJim Quinlan <jim2101024@gmail.com>2020-01-03 22:04:29 +0300
committerPhilipp Zabel <p.zabel@pengutronix.de>2020-01-06 12:02:03 +0300
commit4cf176e52397853e4a4dd37e917c5eafb47ba8d1 (patch)
tree0c20553ef5bc0b5490ef1072b10caee9e7af1f77 /drivers/reset/reset-brcmstb-rescal.c
parentf6e1405f7a1698234e5143a806453d60f893c651 (diff)
downloadlinux-4cf176e52397853e4a4dd37e917c5eafb47ba8d1.tar.xz
reset: Add Broadcom STB RESCAL reset controller
On BCM7216 there is a special purpose reset controller named RESCAL (reset calibration) which is necessary for SATA and PCIe0/1 to operate correctly. This commit adds support for such a reset controller to be available. Signed-off-by: Jim Quinlan <jim2101024@gmail.com> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Diffstat (limited to 'drivers/reset/reset-brcmstb-rescal.c')
-rw-r--r--drivers/reset/reset-brcmstb-rescal.c107
1 files changed, 107 insertions, 0 deletions
diff --git a/drivers/reset/reset-brcmstb-rescal.c b/drivers/reset/reset-brcmstb-rescal.c
new file mode 100644
index 000000000000..b6f074d6a65f
--- /dev/null
+++ b/drivers/reset/reset-brcmstb-rescal.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2018-2020 Broadcom */
+
+#include <linux/device.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+
+#define BRCM_RESCAL_START 0x0
+#define BRCM_RESCAL_START_BIT BIT(0)
+#define BRCM_RESCAL_CTRL 0x4
+#define BRCM_RESCAL_STATUS 0x8
+#define BRCM_RESCAL_STATUS_BIT BIT(0)
+
+struct brcm_rescal_reset {
+ void __iomem *base;
+ struct device *dev;
+ struct reset_controller_dev rcdev;
+};
+
+static int brcm_rescal_reset_set(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct brcm_rescal_reset *data =
+ container_of(rcdev, struct brcm_rescal_reset, rcdev);
+ void __iomem *base = data->base;
+ u32 reg;
+ int ret;
+
+ reg = readl(base + BRCM_RESCAL_START);
+ writel(reg | BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
+ reg = readl(base + BRCM_RESCAL_START);
+ if (!(reg & BRCM_RESCAL_START_BIT)) {
+ dev_err(data->dev, "failed to start SATA/PCIe rescal\n");
+ return -EIO;
+ }
+
+ ret = readl_poll_timeout(base + BRCM_RESCAL_STATUS, reg,
+ !(reg & BRCM_RESCAL_STATUS_BIT), 100, 1000);
+ if (ret) {
+ dev_err(data->dev, "time out on SATA/PCIe rescal\n");
+ return ret;
+ }
+
+ reg = readl(base + BRCM_RESCAL_START);
+ writel(reg & ~BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
+
+ dev_dbg(data->dev, "SATA/PCIe rescal success\n");
+
+ return 0;
+}
+
+static int brcm_rescal_reset_xlate(struct reset_controller_dev *rcdev,
+ const struct of_phandle_args *reset_spec)
+{
+ /* This is needed if #reset-cells == 0. */
+ return 0;
+}
+
+static const struct reset_control_ops brcm_rescal_reset_ops = {
+ .reset = brcm_rescal_reset_set,
+};
+
+static int brcm_rescal_reset_probe(struct platform_device *pdev)
+{
+ struct brcm_rescal_reset *data;
+ struct resource *res;
+
+ data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ data->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(data->base))
+ return PTR_ERR(data->base);
+
+ data->rcdev.owner = THIS_MODULE;
+ data->rcdev.nr_resets = 1;
+ data->rcdev.ops = &brcm_rescal_reset_ops;
+ data->rcdev.of_node = pdev->dev.of_node;
+ data->rcdev.of_xlate = brcm_rescal_reset_xlate;
+ data->dev = &pdev->dev;
+
+ return devm_reset_controller_register(&pdev->dev, &data->rcdev);
+}
+
+static const struct of_device_id brcm_rescal_reset_of_match[] = {
+ { .compatible = "brcm,bcm7216-pcie-sata-rescal" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, brcm_rescal_reset_of_match);
+
+static struct platform_driver brcm_rescal_reset_driver = {
+ .probe = brcm_rescal_reset_probe,
+ .driver = {
+ .name = "brcm-rescal-reset",
+ .of_match_table = brcm_rescal_reset_of_match,
+ }
+};
+module_platform_driver(brcm_rescal_reset_driver);
+
+MODULE_AUTHOR("Broadcom");
+MODULE_DESCRIPTION("Broadcom SATA/PCIe rescal reset controller");
+MODULE_LICENSE("GPL v2");