--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Nuvoton Technology corporation.
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/reset-controller.h>
+#include <linux/spinlock.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/of_address.h>
+
+/* NPCM7xx GCR registers */
+#define NPCM_MDLR_OFFSET 0x7C
+#define NPCM_MDLR_USBD0 BIT(9)
+#define NPCM_MDLR_USBD1 BIT(8)
+#define NPCM_MDLR_USBD2_4 BIT(21)
+#define NPCM_MDLR_USBD5_9 BIT(22)
+
+#define NPCM_USB1PHYCTL_OFFSET 0x140
+#define NPCM_USB2PHYCTL_OFFSET 0x144
+#define NPCM_USBXPHYCTL_RS BIT(28)
+
+/* NPCM7xx Reset registers */
+#define NPCM_SWRSTR 0x14
+#define NPCM_SWRST BIT(2)
+
+#define NPCM_IPSRST1 0x20
+#define NPCM_IPSRST1_USBD1 BIT(5)
+#define NPCM_IPSRST1_USBD2 BIT(8)
+#define NPCM_IPSRST1_USBD3 BIT(25)
+#define NPCM_IPSRST1_USBD4 BIT(22)
+#define NPCM_IPSRST1_USBD5 BIT(23)
+#define NPCM_IPSRST1_USBD6 BIT(24)
+
+#define NPCM_IPSRST2 0x24
+#define NPCM_IPSRST2_USB_HOST BIT(26)
+
+#define NPCM_IPSRST3 0x34
+#define NPCM_IPSRST3_USBD0 BIT(4)
+#define NPCM_IPSRST3_USBD7 BIT(5)
+#define NPCM_IPSRST3_USBD8 BIT(6)
+#define NPCM_IPSRST3_USBD9 BIT(7)
+#define NPCM_IPSRST3_USBPHY1 BIT(24)
+#define NPCM_IPSRST3_USBPHY2 BIT(25)
+
+#define NPCM_RC_RESETS_PER_REG 32
+#define NPCM_MASK_RESETS GENMASK(4, 0)
+
+struct npcm_rc_data {
+ struct reset_controller_dev rcdev;
+ struct notifier_block restart_nb;
+ u32 sw_reset_number;
+ void __iomem *base;
+ spinlock_t lock;
+};
+
+#define to_rc_data(p) container_of(p, struct npcm_rc_data, rcdev)
+
+static int npcm_rc_restart(struct notifier_block *nb, unsigned long mode,
+ void *cmd)
+{
+ struct npcm_rc_data *rc = container_of(nb, struct npcm_rc_data,
+ restart_nb);
+
+ writel(NPCM_SWRST << rc->sw_reset_number, rc->base + NPCM_SWRSTR);
+ mdelay(1000);
+
+ pr_emerg("%s: unable to restart system\n", __func__);
+
+ return NOTIFY_DONE;
+}
+
+static int npcm_rc_setclear_reset(struct reset_controller_dev *rcdev,
+ unsigned long id, bool set)
+{
+ struct npcm_rc_data *rc = to_rc_data(rcdev);
+ unsigned int rst_bit = BIT(id & NPCM_MASK_RESETS);
+ unsigned int ctrl_offset = id >> 8;
+ unsigned long flags;
+ u32 stat;
+
+ spin_lock_irqsave(&rc->lock, flags);
+ stat = readl(rc->base + ctrl_offset);
+ if (set)
+ writel(stat | rst_bit, rc->base + ctrl_offset);
+ else
+ writel(stat & ~rst_bit, rc->base + ctrl_offset);
+ spin_unlock_irqrestore(&rc->lock, flags);
+
+ return 0;
+}
+
+static int npcm_rc_assert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ return npcm_rc_setclear_reset(rcdev, id, true);
+}
+
+static int npcm_rc_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return npcm_rc_setclear_reset(rcdev, id, false);
+}
+
+static int npcm_rc_status(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct npcm_rc_data *rc = to_rc_data(rcdev);
+ unsigned int rst_bit = BIT(id & NPCM_MASK_RESETS);
+ unsigned int ctrl_offset = id >> 8;
+
+ return (readl(rc->base + ctrl_offset) & rst_bit);
+}
+
+static int npcm_reset_xlate(struct reset_controller_dev *rcdev,
+ const struct of_phandle_args *reset_spec)
+{
+ unsigned int offset, bit;
+
+ offset = reset_spec->args[0];
+ if (offset != NPCM_IPSRST1 && offset != NPCM_IPSRST2 &&
+ offset != NPCM_IPSRST3) {
+ dev_err(rcdev->dev, "Error reset register (0x%x)\n", offset);
+ return -EINVAL;
+ }
+ bit = reset_spec->args[1];
+ if (bit >= NPCM_RC_RESETS_PER_REG) {
+ dev_err(rcdev->dev, "Error reset number (%d)\n", bit);
+ return -EINVAL;
+ }
+
+ return (offset << 8) | bit;
+}
+
+static const struct of_device_id npcm_rc_match[] = {
+ { .compatible = "nuvoton,npcm750-reset",
+ .data = (void *)"nuvoton,npcm750-gcr" },
+ { }
+};
+
+/*
+ * The following procedure should be observed in USB PHY, USB device and
+ * USB host initialization at BMC boot
+ */
+static int npcm_usb_reset(struct platform_device *pdev, struct npcm_rc_data *rc)
+{
+ u32 mdlr, iprst1, iprst2, iprst3;
+ struct device *dev = &pdev->dev;
+ struct regmap *gcr_regmap;
+ u32 ipsrst1_bits = 0;
+ u32 ipsrst2_bits = NPCM_IPSRST2_USB_HOST;
+ u32 ipsrst3_bits = 0;
+ const char *gcr_dt;
+
+ gcr_dt = (const char *)
+ of_match_device(dev->driver->of_match_table, dev)->data;
+
+ gcr_regmap = syscon_regmap_lookup_by_compatible(gcr_dt);
+ if (IS_ERR(gcr_regmap)) {
+ dev_err(&pdev->dev, "Failed to find %s\n", gcr_dt);
+ return PTR_ERR(gcr_regmap);
+ }
+
+ /* checking which USB device is enabled */
+ regmap_read(gcr_regmap, NPCM_MDLR_OFFSET, &mdlr);
+ if (!(mdlr & NPCM_MDLR_USBD0))
+ ipsrst3_bits |= NPCM_IPSRST3_USBD0;
+ if (!(mdlr & NPCM_MDLR_USBD1))
+ ipsrst1_bits |= NPCM_IPSRST1_USBD1;
+ if (!(mdlr & NPCM_MDLR_USBD2_4))
+ ipsrst1_bits |= (NPCM_IPSRST1_USBD2 |
+ NPCM_IPSRST1_USBD3 |
+ NPCM_IPSRST1_USBD4);
+ if (!(mdlr & NPCM_MDLR_USBD0)) {
+ ipsrst1_bits |= (NPCM_IPSRST1_USBD5 |
+ NPCM_IPSRST1_USBD6);
+ ipsrst3_bits |= (NPCM_IPSRST3_USBD7 |
+ NPCM_IPSRST3_USBD8 |
+ NPCM_IPSRST3_USBD9);
+ }
+
+ /* assert reset USB PHY and USB devices */
+ iprst1 = readl(rc->base + NPCM_IPSRST1);
+ iprst2 = readl(rc->base + NPCM_IPSRST2);
+ iprst3 = readl(rc->base + NPCM_IPSRST3);
+
+ iprst1 |= ipsrst1_bits;
+ iprst2 |= ipsrst2_bits;
+ iprst3 |= (ipsrst3_bits | NPCM_IPSRST3_USBPHY1 |
+ NPCM_IPSRST3_USBPHY2);
+
+ writel(iprst1, rc->base + NPCM_IPSRST1);
+ writel(iprst2, rc->base + NPCM_IPSRST2);
+ writel(iprst3, rc->base + NPCM_IPSRST3);
+
+ /* clear USB PHY RS bit */
+ regmap_update_bits(gcr_regmap, NPCM_USB1PHYCTL_OFFSET,
+ NPCM_USBXPHYCTL_RS, 0);
+ regmap_update_bits(gcr_regmap, NPCM_USB2PHYCTL_OFFSET,
+ NPCM_USBXPHYCTL_RS, 0);
+
+ /* deassert reset USB PHY */
+ iprst3 &= ~(NPCM_IPSRST3_USBPHY1 | NPCM_IPSRST3_USBPHY2);
+ writel(iprst3, rc->base + NPCM_IPSRST3);
+
+ udelay(50);
+
+ /* set USB PHY RS bit */
+ regmap_update_bits(gcr_regmap, NPCM_USB1PHYCTL_OFFSET,
+ NPCM_USBXPHYCTL_RS, NPCM_USBXPHYCTL_RS);
+ regmap_update_bits(gcr_regmap, NPCM_USB2PHYCTL_OFFSET,
+ NPCM_USBXPHYCTL_RS, NPCM_USBXPHYCTL_RS);
+
+ /* deassert reset USB devices*/
+ iprst1 &= ~ipsrst1_bits;
+ iprst2 &= ~ipsrst2_bits;
+ iprst3 &= ~ipsrst3_bits;
+
+ writel(iprst1, rc->base + NPCM_IPSRST1);
+ writel(iprst2, rc->base + NPCM_IPSRST2);
+ writel(iprst3, rc->base + NPCM_IPSRST3);
+
+ return 0;
+}
+
+static const struct reset_control_ops npcm_rc_ops = {
+ .assert = npcm_rc_assert,
+ .deassert = npcm_rc_deassert,
+ .status = npcm_rc_status,
+};
+
+static int npcm_rc_probe(struct platform_device *pdev)
+{
+ struct npcm_rc_data *rc;
+ int ret;
+
+ rc = devm_kzalloc(&pdev->dev, sizeof(*rc), GFP_KERNEL);
+ if (!rc)
+ return -ENOMEM;
+
+ rc->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(rc->base))
+ return PTR_ERR(rc->base);
+
+ spin_lock_init(&rc->lock);
+
+ rc->rcdev.owner = THIS_MODULE;
+ rc->rcdev.ops = &npcm_rc_ops;
+ rc->rcdev.of_node = pdev->dev.of_node;
+ rc->rcdev.of_reset_n_cells = 2;
+ rc->rcdev.of_xlate = npcm_reset_xlate;
+
+ platform_set_drvdata(pdev, rc);
+
+ ret = devm_reset_controller_register(&pdev->dev, &rc->rcdev);
+ if (ret) {
+ dev_err(&pdev->dev, "unable to register device\n");
+ return ret;
+ }
+
+ if (npcm_usb_reset(pdev, rc))
+ dev_warn(&pdev->dev, "NPCM USB reset failed, can cause issues with UDC and USB host\n");
+
+ if (!of_property_read_u32(pdev->dev.of_node, "nuvoton,sw-reset-number",
+ &rc->sw_reset_number)) {
+ if (rc->sw_reset_number && rc->sw_reset_number < 5) {
+ rc->restart_nb.priority = 192,
+ rc->restart_nb.notifier_call = npcm_rc_restart,
+ ret = register_restart_handler(&rc->restart_nb);
+ if (ret)
+ dev_warn(&pdev->dev, "failed to register restart handler\n");
+ }
+ }
+
+ return ret;
+}
+
+static struct platform_driver npcm_rc_driver = {
+ .probe = npcm_rc_probe,
+ .driver = {
+ .name = "npcm-reset",
+ .of_match_table = npcm_rc_match,
+ .suppress_bind_attrs = true,
+ },
+};
+builtin_platform_driver(npcm_rc_driver);
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