On Qualcomm systems, the setup buffer and even buffers are in
a bad state at interrupt handling, so invalidate the dcache lines
for the setup_buf and event buffer to make sure we read correct
data written by the hardware.

This fixes the following error:
dwc3-generic-peripheral usb@a600000: UNKNOWN IRQ type -1
dwc3-generic-peripheral usb@a600000: UNKNOWN IRQ type 4673109

and invalid situation in dwc3_gadget_giveback() because setup_buf content
is read at 0s and leads to fatal crash fixed by [1].

[1] 
https://lore.kernel.org/all/20240528-topic-sm8x50-dwc3-gadget-crash-fix-v1-1-58434ab4b...@linaro.org/

Signed-off-by: Neil Armstrong <neil.armstr...@linaro.org>
---
 drivers/usb/dwc3/ep0.c    | 2 ++
 drivers/usb/dwc3/gadget.c | 2 ++
 drivers/usb/dwc3/io.h     | 8 ++++++++
 3 files changed, 12 insertions(+)

diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 0c7e0123368..fc1d5892106 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -743,6 +743,8 @@ static void dwc3_ep0_inspect_setup(struct dwc3 *dwc,
        if (!dwc->gadget_driver)
                goto out;
 
+       dwc3_invalidate_cache(ctrl, sizeof(*ctrl));
+
        len = le16_to_cpu(ctrl->wLength);
        if (!len) {
                dwc->three_stage_setup = false;
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index d41b590afb8..0bc9aee4daa 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2503,6 +2503,8 @@ static irqreturn_t dwc3_process_event_buf(struct dwc3 
*dwc, u32 buf)
        while (left > 0) {
                union dwc3_event event;
 
+               dwc3_invalidate_cache((uintptr_t)evt->buf, evt->length);
+
                event.raw = *(u32 *) (evt->buf + evt->lpos);
 
                dwc3_process_event_entry(dwc, &event);
diff --git a/drivers/usb/dwc3/io.h b/drivers/usb/dwc3/io.h
index 1aaf5413c6d..7cf05203b0d 100644
--- a/drivers/usb/dwc3/io.h
+++ b/drivers/usb/dwc3/io.h
@@ -55,4 +55,12 @@ static inline void dwc3_flush_cache(uintptr_t addr, int 
length)
 
        flush_dcache_range(start_addr, end_addr);
 }
+
+static inline void dwc3_invalidate_cache(uintptr_t addr, int length)
+{
+       uintptr_t start_addr = (uintptr_t)addr & ~(ARCH_DMA_MINALIGN - 1);
+       uintptr_t end_addr = ALIGN((uintptr_t)addr + length, ARCH_DMA_MINALIGN);
+
+       invalidate_dcache_range(start_addr, end_addr);
+}
 #endif /* __DRIVERS_USB_DWC3_IO_H */

-- 
2.34.1

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