[U-Boot] [PATCH] usb: ehci: add ehci max xfer size ehci config entry

[Gilles DOFFE]

Some USB sticks cannot handle SIZE_MAX bytes (65535) blocks transfer,
leading to 'EHCI timed out on TD' errors.
As it is hardly predictable, this commit adds a configuration option
to easily reduce this EHCI max transfer size. The default value is 65535
which corresponds to size_t max value (SIZE_MAX).

Signed-off-by: Gilles DOFFE <gilles.doffe at savoirfairelinux.com>
---
 drivers/usb/host/Kconfig    | 7 +++++++
 drivers/usb/host/ehci-hcd.c | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
index 30c6b69be8..62054c9c7a 100644
--- a/drivers/usb/host/Kconfig
+++ b/drivers/usb/host/Kconfig
@@ -222,6 +222,13 @@ config USB_EHCI_FSL
 	select  CONFIG_EHCI_HCD_INIT_AFTER_RESET
 	---help---
 	  Enables support for the on-chip EHCI controller on FSL chips.
+
+config USB_EHCI_MAX_XFER_SIZE
+    int "USB EHCI max transfer size. The default value is 65535 which
+    corresponds to size_t max value (SIZE_MAX)."
+    default 65535
+    range 1 65535
+
 endif # USB_EHCI_HCD
 
 config USB_OHCI_HCD
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 61a61abb21..8be1319079 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -1614,7 +1614,7 @@ static int ehci_get_max_xfer_size(struct udevice *dev, size_t *size)
 	 * EHCD can handle any transfer length as long as there is enough
 	 * free heap space left, hence set the theoretical max number here.
 	 */
-	*size = SIZE_MAX;
+	*size = CONFIG_USB_EHCI_MAX_XFER_SIZE;
 
 	return 0;
 }
-- 
2.20.1