1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2011 Google, Inc. 4 * 5 * This software is licensed under the terms of the GNU General Public 6 * License version 2, as published by the Free Software Foundation, and 7 * may be copied, distributed, and modified under those terms. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 */ 15 16 #include <linux/export.h> 17 #include <linux/kernel.h> 18 #include <linux/usb.h> 19 #include <linux/io.h> 20 #include <linux/usb/otg.h> 21 #include <linux/usb/ulpi.h> 22 23 #define ULPI_VIEW_WAKEUP (1 << 31) 24 #define ULPI_VIEW_RUN (1 << 30) 25 #define ULPI_VIEW_WRITE (1 << 29) 26 #define ULPI_VIEW_READ (0 << 29) 27 #define ULPI_VIEW_ADDR(x) (((x) & 0xff) << 16) 28 #define ULPI_VIEW_DATA_READ(x) (((x) >> 8) & 0xff) 29 #define ULPI_VIEW_DATA_WRITE(x) ((x) & 0xff) 30 31 static int ulpi_viewport_wait(void __iomem *view, u32 mask) 32 { 33 unsigned long usec = 2000; 34 35 while (usec--) { 36 if (!(readl(view) & mask)) 37 return 0; 38 39 udelay(1); 40 } 41 42 return -ETIMEDOUT; 43 } 44 45 static int ulpi_viewport_read(struct usb_phy *otg, u32 reg) 46 { 47 int ret; 48 void __iomem *view = otg->io_priv; 49 50 writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view); 51 ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP); 52 if (ret) 53 return ret; 54 55 writel(ULPI_VIEW_RUN | ULPI_VIEW_READ | ULPI_VIEW_ADDR(reg), view); 56 ret = ulpi_viewport_wait(view, ULPI_VIEW_RUN); 57 if (ret) 58 return ret; 59 60 return ULPI_VIEW_DATA_READ(readl(view)); 61 } 62 63 static int ulpi_viewport_write(struct usb_phy *otg, u32 val, u32 reg) 64 { 65 int ret; 66 void __iomem *view = otg->io_priv; 67 68 writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view); 69 ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP); 70 if (ret) 71 return ret; 72 73 writel(ULPI_VIEW_RUN | ULPI_VIEW_WRITE | ULPI_VIEW_DATA_WRITE(val) | 74 ULPI_VIEW_ADDR(reg), view); 75 76 return ulpi_viewport_wait(view, ULPI_VIEW_RUN); 77 } 78 79 struct usb_phy_io_ops ulpi_viewport_access_ops = { 80 .read = ulpi_viewport_read, 81 .write = ulpi_viewport_write, 82 }; 83 EXPORT_SYMBOL_GPL(ulpi_viewport_access_ops); 84