1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2011 Google, Inc. 4 */ 5 6 #include <linux/export.h> 7 #include <linux/kernel.h> 8 #include <linux/usb.h> 9 #include <linux/io.h> 10 #include <linux/usb/otg.h> 11 #include <linux/usb/ulpi.h> 12 13 #define ULPI_VIEW_WAKEUP (1 << 31) 14 #define ULPI_VIEW_RUN (1 << 30) 15 #define ULPI_VIEW_WRITE (1 << 29) 16 #define ULPI_VIEW_READ (0 << 29) 17 #define ULPI_VIEW_ADDR(x) (((x) & 0xff) << 16) 18 #define ULPI_VIEW_DATA_READ(x) (((x) >> 8) & 0xff) 19 #define ULPI_VIEW_DATA_WRITE(x) ((x) & 0xff) 20 21 static int ulpi_viewport_wait(void __iomem *view, u32 mask) 22 { 23 unsigned long usec = 2000; 24 25 while (usec--) { 26 if (!(readl(view) & mask)) 27 return 0; 28 29 udelay(1); 30 } 31 32 return -ETIMEDOUT; 33 } 34 35 static int ulpi_viewport_read(struct usb_phy *otg, u32 reg) 36 { 37 int ret; 38 void __iomem *view = otg->io_priv; 39 40 writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view); 41 ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP); 42 if (ret) 43 return ret; 44 45 writel(ULPI_VIEW_RUN | ULPI_VIEW_READ | ULPI_VIEW_ADDR(reg), view); 46 ret = ulpi_viewport_wait(view, ULPI_VIEW_RUN); 47 if (ret) 48 return ret; 49 50 return ULPI_VIEW_DATA_READ(readl(view)); 51 } 52 53 static int ulpi_viewport_write(struct usb_phy *otg, u32 val, u32 reg) 54 { 55 int ret; 56 void __iomem *view = otg->io_priv; 57 58 writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view); 59 ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP); 60 if (ret) 61 return ret; 62 63 writel(ULPI_VIEW_RUN | ULPI_VIEW_WRITE | ULPI_VIEW_DATA_WRITE(val) | 64 ULPI_VIEW_ADDR(reg), view); 65 66 return ulpi_viewport_wait(view, ULPI_VIEW_RUN); 67 } 68 69 struct usb_phy_io_ops ulpi_viewport_access_ops = { 70 .read = ulpi_viewport_read, 71 .write = ulpi_viewport_write, 72 }; 73 EXPORT_SYMBOL_GPL(ulpi_viewport_access_ops); 74