arch/arm/mach-snapdragon/of_fixup.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * OF_LIVE devicetree fixup.
   4  *
   5  * This file implements runtime fixups for Qualcomm DT to improve
   6  * compatibility with U-Boot. This includes adjusting the USB nodes
   7  * to only use USB high-speed, as well as remapping volume buttons
   8  * to behave as up/down for navigating U-Boot.
   9  *
  10  * We use OF_LIVE for this rather than early FDT fixup for a couple
  11  * of reasons: it has a much nicer API, is most likely more efficient,
  12  * and our changes are only applied to U-Boot. This allows us to use a
  13  * DT designed for Linux, run U-Boot with a modified version, and then
  14  * boot Linux with the original FDT.
  15  *
  16  * Copyright (c) 2024 Linaro Ltd.
  17  *   Author: Caleb Connolly <caleb.connolly@linaro.org>
  18  */
  19
  20 #include <dt-bindings/input/linux-event-codes.h>
  21 #include <dm/of_access.h>
  22 #include <dm/of.h>
  23 #include <fdt_support.h>
  24 #include <linux/errno.h>
  25 #include <time.h>
  26
  27 /* U-Boot only supports USB high-speed mode on Qualcomm platforms with DWC3
  28  * USB controllers. Rather than requiring source level DT changes, we fix up
  29  * DT here. This improves compatibility with upstream DT and simplifies the
  30  * porting process for new devices.
  31  */
  32 static int fixup_qcom_dwc3(struct device_node *glue_np)
  33 {
  34         struct device_node *dwc3;
  35         int ret, len, hsphy_idx = 1;
  36         const __be32 *phandles;
  37         const char *second_phy_name;
  38
  39         debug("Fixing up %s\n", glue_np->name);
  40
  41         /* Tell the glue driver to configure the wrapper for high-speed only operation */
  42         ret = of_write_prop(glue_np, "qcom,select-utmi-as-pipe-clk", 0, NULL);
  43         if (ret) {
  44                 log_err("Failed to add property 'qcom,select-utmi-as-pipe-clk': %d\n", ret);
  45                 return ret;
  46         }
  47
  48         /* Find the DWC3 node itself */
  49         dwc3 = of_find_compatible_node(glue_np, NULL, "snps,dwc3");
  50         if (!dwc3) {
  51                 log_err("Failed to find dwc3 node\n");
  52                 return -ENOENT;
  53         }
  54
  55         phandles = of_get_property(dwc3, "phys", &len);
  56         len /= sizeof(*phandles);
  57         if (len == 1) {
  58                 log_debug("Only one phy, not a superspeed controller\n");
  59                 return 0;
  60         }
  61
  62         /* Figure out if the superspeed phy is present and if so then which phy is it? */
  63         ret = of_property_read_string_index(dwc3, "phy-names", 1, &second_phy_name);
  64         if (ret == -ENODATA) {
  65                 log_debug("Only one phy, not a super-speed controller\n");
  66                 return 0;
  67         } else if (ret) {
  68                 log_err("Failed to read second phy name: %d\n", ret);
  69                 return ret;
  70         }
  71
  72         if (!strncmp("usb3-phy", second_phy_name, strlen("usb3-phy"))) {
  73                 log_debug("Second phy isn't superspeed (is '%s') assuming first phy is SS\n",
  74                           second_phy_name);
  75                 hsphy_idx = 0;
  76         }
  77
  78         /* Overwrite the "phys" property to only contain the high-speed phy */
  79         ret = of_write_prop(dwc3, "phys", sizeof(*phandles), phandles + hsphy_idx);
  80         if (ret) {
  81                 log_err("Failed to overwrite 'phys' property: %d\n", ret);
  82                 return ret;
  83         }
  84
  85         /* Overwrite "phy-names" to only contain a single entry */
  86         ret = of_write_prop(dwc3, "phy-names", strlen("usb2-phy"), "usb2-phy");
  87         if (ret) {
  88                 log_err("Failed to overwrite 'phy-names' property: %d\n", ret);
  89                 return ret;
  90         }
  91
  92         ret = of_write_prop(dwc3, "maximum-speed", strlen("high-speed"), "high-speed");
  93         if (ret) {
  94                 log_err("Failed to set 'maximum-speed' property: %d\n", ret);
  95                 return ret;
  96         }
  97
  98         return 0;
  99 }
 100
 101 static void fixup_usb_nodes(void)
 102 {
 103         struct device_node *glue_np = NULL;
 104         int ret;
 105
 106         while ((glue_np = of_find_compatible_node(glue_np, NULL, "qcom,dwc3"))) {
 107                 ret = fixup_qcom_dwc3(glue_np);
 108                 if (ret)
 109                         log_warning("Failed to fixup node %s: %d\n", glue_np->name, ret);
 110         }
 111 }
 112
 113 #define time_call(func, ...) \
 114         do { \
 115                 u64 start = timer_get_us(); \
 116                 func(__VA_ARGS__); \
 117                 debug(#func " took %lluus\n", timer_get_us() - start); \
 118         } while (0)
 119
 120 void qcom_of_fixup_nodes(void)
 121 {
 122         time_call(fixup_usb_nodes);
 123 }