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arch: arm: mach-snapdragon: Auto-detect USB SSPHY driver support

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Automatically detect super-speed USB PHY driver availability and
skip the USB speed fixup if driver is available, eliminating the need
for manual configuration.

Previously, U-Boot unconditionally limited USB to high-speed mode
on all Qualcomm platforms because most lacked super-speed PHY
drivers.

This change implements runtime detection that checks if a PHY
driver exists for the super-speed PHY node referenced by the DWC3
controller. The fixup is automatically skipped when a compatible
driver is found, allowing the hardware to operate at full
capability. Platforms without super-speed PHY drivers continue to
receive the fixup automatically.

Signed-off-by: Balaji Selvanathan <balaji.selvanathan@oss.qualcomm.com>
[casey: rebased on flat-dwc3 dt support + fix Balaji's signoff]
[casey: make erroneous printf() a debug() again]
Link: https://patch.msgid.link/20251203110735.1959862-5-balaji.selvanathan@oss.qualcomm.com
Signed-off-by: Casey Connolly <casey.connolly@linaro.org>
This commit is contained in:
Balaji Selvanathan
2026-04-27 12:38:44 +02:00
committed by Casey Connolly
parent 2c93971ba3
commit 5ebc47d984
1 changed files with 111 additions and 17 deletions
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arch/arm/mach-snapdragon/of_fixup.c
+111 -17
View File
@@ -4,7 +4,7 @@
*
* 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.
* to only use USB high-speed if SSPHY driver is not available.
*
* 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,
@@ -21,26 +21,107 @@
#include <dt-bindings/input/linux-event-codes.h>
#include <dm/of_access.h>
#include <dm/of.h>
#include <dm/device.h>
#include <dm/lists.h>
#include <event.h>
#include <fdt_support.h>
#include <linux/errno.h>
#include <linker_lists.h>
#include <stdlib.h>
#include <time.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.
/**
* find_ssphy_node() - Find the super-speed PHY node referenced by DWC3
* @dwc3: DWC3 device node
*
* Returns: Pointer to SS-PHY node if found, NULL otherwise
*/
static struct device_node *find_ssphy_node(struct device_node *dwc3)
{
const __be32 *phandles;
const char *phy_name;
int len, i, ret;
phandles = of_get_property(dwc3, "phys", &len);
if (!phandles)
return NULL;
len /= sizeof(*phandles);
/* Iterate through PHY phandles to find the SS-PHY */
for (i = 0; i < len; i++) {
ret = of_property_read_string_index(dwc3, "phy-names", i, &phy_name);
if (ret)
continue;
/* Check if this is the super-speed PHY */
if (!strncmp("usb3-phy", phy_name, strlen("usb3-phy")) ||
!strncmp("usb3_phy", phy_name, strlen("usb3_phy"))) {
return of_find_node_by_phandle(NULL, be32_to_cpu(phandles[i]));
}
}
return NULL;
}
/**
* has_driver_for_node() - Check if any PHY driver can bind to this node
* @np: Device node to check
*
* Returns: true if a PHY driver with matching compatible string exists, false otherwise
*/
static bool has_driver_for_node(struct device_node *np)
{
struct driver *driver = ll_entry_start(struct driver, driver);
const int n_ents = ll_entry_count(struct driver, driver);
const char *compat_list, *compat;
int compat_length, i;
struct driver *entry;
if (!np)
return false;
/* Get compatible strings from the node */
compat_list = of_get_property(np, "compatible", &compat_length);
if (!compat_list)
return false;
/* Check each compatible string against PHY drivers only */
for (i = 0; i < compat_length; i += strlen(compat) + 1) {
compat = compat_list + i;
/* Iterate through all registered drivers */
for (entry = driver; entry != driver + n_ents; entry++) {
const struct udevice_id *of_match = entry->of_match;
/* Skip non-PHY drivers to improve performance */
if (entry->id != UCLASS_PHY)
continue;
if (!of_match)
continue;
while (of_match->compatible) {
if (!strcmp(of_match->compatible, compat)) {
debug("Found PHY driver '%s' for SS-PHY compatible '%s'\n",
entry->name, compat);
return true;
}
of_match++;
}
}
}
return false;
}
static int fixup_qcom_dwc3(struct device_node *root, struct device_node *glue_np, bool flat)
{
struct device_node *dwc3;
struct device_node *dwc3, *ssphy_np;
int ret, len, hsphy_idx = 1;
const __be32 *phandles;
const char *second_phy_name;
debug("Fixing up %s\n", glue_np->name);
/* New DT flattens the glue and controller into a single node. */
if (flat) {
dwc3 = glue_np;
@@ -54,30 +135,43 @@ static int fixup_qcom_dwc3(struct device_node *root, struct device_node *glue_np
}
}
/* 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;
}
debug("Checking USB configuration for %s\n", dwc3->name);
phandles = of_get_property(dwc3, "phys", &len);
len /= sizeof(*phandles);
if (len == 1) {
log_debug("Only one phy, not a superspeed controller\n");
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? */
/* Figure out if the superspeed phy is present */
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");
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;
}
/* Find the super-speed PHY node and check if a driver is available */
ssphy_np = find_ssphy_node(dwc3);
if (ssphy_np && has_driver_for_node(ssphy_np)) {
debug("Skipping USB fixup for %s (SS-PHY driver available)\n",
dwc3->name);
return 0;
}
/* No driver available - apply the fixup */
debug("Applying USB high-speed fixup to %s\n", dwc3->name);
/* Tell the glue driver to configure the wrapper for high-speed only operation */
ret = of_write_prop(dwc3, "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;
}
/*
* Determine which phy is the superspeed phy by checking the name of the second phy
* since it is typically the superspeed one.