Re: [PATCH v3 10/14] mach-snapdragon: fixup USB nodes

Hi Caleb,

On Tue, 19 Mar 2024 at 17:52, Caleb Connolly caleb.connolly@linaro.org wrote:

We don't support USB super-speed in U-Boot yet, we lack the SS PHY drivers, however from my testing even with a PHY driver there seem to be other issues when talking to super-speed peripherals.

In pursuit of maintaining upstream DT compatibility,

I can understand the reasoning behind this but since we enable these fixups for every Qcom platform it may turn out to be counter productive. There can be embedded use-cases where bootup times have stringent requirements. Also, depending upon CPU speed/freq the add-on times due to these can be significant.

I would suggest we rather solve these USB issues either via a common Qcom *-u-boot.dtsi file which can be included for every board.

-Sumit

and simplifying porting for new devices, let's implement the DT fixups necessary to configure USB in high-speed only mode at runtime. The pattern is identical for all Qualcomm boards that use the Synaptics DWC3 controller:

• Add an additional property on the Qualcomm wrapper node
• Remove the super-speed phy phandle and phy-name entries.

Signed-off-by: Caleb Connolly caleb.connolly@linaro.org

arch/arm/mach-snapdragon/Makefile | 1 + arch/arm/mach-snapdragon/board.c | 3 + arch/arm/mach-snapdragon/of_fixup.c | 115 +++++++++++++++++++++++++++++++++++ arch/arm/mach-snapdragon/qcom-priv.h | 19 ++++++ 4 files changed, 138 insertions(+)

diff --git a/arch/arm/mach-snapdragon/Makefile b/arch/arm/mach-snapdragon/Makefile index 857171e593da..7a4495c8108f 100644 --- a/arch/arm/mach-snapdragon/Makefile +++ b/arch/arm/mach-snapdragon/Makefile @@ -2,4 +2,5 @@ # # (C) Copyright 2015 Mateusz Kulikowski mateusz.kulikowski@gmail.com

obj-y += board.o +obj-$(CONFIG_OF_LIVE) += of_fixup.o diff --git a/arch/arm/mach-snapdragon/board.c b/arch/arm/mach-snapdragon/board.c index 6f762fc948bf..65e4c61e866a 100644 --- a/arch/arm/mach-snapdragon/board.c +++ b/arch/arm/mach-snapdragon/board.c @@ -27,8 +27,10 @@ #include <fdt_support.h> #include <usb.h> #include <sort.h>

+#include "qcom-priv.h"

DECLARE_GLOBAL_DATA_PTR;

static struct mm_region rbx_mem_map[CONFIG_NR_DRAM_BANKS + 2] = { { 0 } };

@@ -159,8 +161,9 @@ void __weak qcom_board_init(void)

int board_init(void) { show_psci_version();

•   qcom_of_fixup_nodes();
    qcom_board_init();
    return 0;
  

}

diff --git a/arch/arm/mach-snapdragon/of_fixup.c b/arch/arm/mach-snapdragon/of_fixup.c new file mode 100644 index 000000000000..6810c8617cc0 --- /dev/null +++ b/arch/arm/mach-snapdragon/of_fixup.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: GPL-2.0+ +/*

• • OF_LIVE devicetree fixup.
• • This file implements runtime fixups for Qualcomm DT to improve
• • compatibility with U-Boot. This includes adjusting the USB nodes
• • to only use USB high-speed, as well as remapping volume buttons
• • to behave as up/down for navigating U-Boot.
• • We use OF_LIVE for this rather than early FDT fixup for a couple
• • of reasons: it has a much nicer API, is most likely more efficient,
• • and our changes are only applied to U-Boot. This allows us to use a
• • DT designed for Linux, run U-Boot with a modified version, and then
• • boot Linux with the original FDT.
• • Copyright (c) 2024 Linaro Ltd.
• • Author: Caleb Connolly caleb.connolly@linaro.org
• */

+#include <dt-bindings/input/linux-event-codes.h> +#include <dm/of_access.h> +#include <dm/of.h> +#include <fdt_support.h> +#include <linux/errno.h>

+/* U-Boot only supports USB high-speed mode on Qualcomm platforms with DWC3

• • USB controllers. Rather than requiring source level DT changes, we fix up
• • DT here. This improves compatibility with upstream DT and simplifies the
• • porting process for new devices.
• */

+static int fixup_qcom_dwc3(struct device_node *glue_np) +{

•   struct device_node *dwc3;
  

•   int ret, len, hsphy_idx = 1;
  

•   const __be32 *phandles;
  

•   const char *second_phy_name;
  

•   debug("Fixing up %s\n", glue_np->name);
  

•   /* Tell the glue driver to configure the wrapper for high-speed only operation */
  

•   ret = of_write_prop(glue_np, "qcom,select-utmi-as-pipe-clk", 0, NULL);
  

•   if (ret) {
  

•           log_err("Failed to add property 'qcom,select-utmi-as-pipe-clk': %d\n", ret);
  

•           return ret;
  

•   }
  

•   /* Find the DWC3 node itself */
  

•   dwc3 = of_find_compatible_node(glue_np, NULL, "snps,dwc3");
  

•   if (!dwc3) {
  

•           log_err("Failed to find dwc3 node\n");
  

•           return -ENOENT;
  

•   }
  

•   phandles = of_get_property(dwc3, "phys", &len);
  

•   len /= sizeof(*phandles);
  

•   if (len == 1) {
  

•           log_debug("Only one phy, not a superspeed controller\n");
  

•           return 0;
  

•   }
  

•   /* Figure out if the superspeed phy is present and if so then which phy is it? */
  

•   ret = of_property_read_string_index(dwc3, "phy-names", 1, &second_phy_name);
  

•   if (ret == -ENODATA) {
  

•           log_debug("Only one phy, not a super-speed controller\n");
  

•           return 0;
  

•   } else if (ret) {
  

•           log_err("Failed to read second phy name: %d\n", ret);
  

•           return ret;
  

•   }
  

•   if (!strncmp("usb3-phy", second_phy_name, strlen("usb3-phy"))) {
  

•           log_debug("Second phy isn't superspeed (is '%s') assuming first phy is SS\n",
  

•                     second_phy_name);
  

•           hsphy_idx = 0;
  

•   }
  

•   /* Overwrite the "phys" property to only contain the high-speed phy */
  

•   ret = of_write_prop(dwc3, "phys", sizeof(*phandles), phandles + hsphy_idx);
  

•   if (ret) {
  

•           log_err("Failed to overwrite 'phys' property: %d\n", ret);
  

•           return ret;
  

•   }
  

•   /* Overwrite "phy-names" to only contain a single entry */
  

•   ret = of_write_prop(dwc3, "phy-names", strlen("usb2-phy"), "usb2-phy");
  

•   if (ret) {
  

•           log_err("Failed to overwrite 'phy-names' property: %d\n", ret);
  

•           return ret;
  

•   }
  

•   ret = of_write_prop(dwc3, "maximum-speed", strlen("high-speed"), "high-speed");
  

•   if (ret) {
  

•           log_err("Failed to set 'maximum-speed' property: %d\n", ret);
  

•           return ret;
  

•   }
  

•   return 0;
  

+}

+static void fixup_usb_nodes(void) +{

•   struct device_node *glue_np = NULL;
  

•   int ret;
  

•   while ((glue_np = of_find_compatible_node(glue_np, NULL, "qcom,dwc3"))) {
  

•           ret = fixup_qcom_dwc3(glue_np);
  

•           if (ret)
  

•                   log_warning("Failed to fixup node %s: %d\n", glue_np->name, ret);
  

•   }
  

+}

+void qcom_of_fixup_nodes(void) +{

•   fixup_usb_nodes();
  

+} diff --git a/arch/arm/mach-snapdragon/qcom-priv.h b/arch/arm/mach-snapdragon/qcom-priv.h new file mode 100644 index 000000000000..d18fd1883b7f --- /dev/null +++ b/arch/arm/mach-snapdragon/qcom-priv.h @@ -0,0 +1,19 @@

+#ifndef __QCOM_PRIV_H__ +#define __QCOM_PRIV_H__

+#if CONFIG_IS_ENABLED(OF_LIVE) +/**

• • qcom_of_fixup_nodes() - Fixup Qualcomm DT nodes
• • Adjusts nodes in the live tree to improve compatibility with U-Boot.
• */

+void qcom_of_fixup_nodes(void); +#else +static inline void qcom_of_fixup_nodes(void) +{

•   log_debug("Unable to dynamically fixup USB nodes, please enable CONFIG_OF_LIVE\n");
  

+} +#endif /* OF_LIVE */

+#endif /* __QCOM_PRIV_H__ */

-- 2.44.0