[PATCH v2] usb: dwc2: reset dwc2 core before dwc2_get_hwparams()

From: Yunzhi Li
Date: Tue Aug 18 2015 - 05:40:58 EST


We initiate dwc2 usb controller in BIOS, dwc2_core_reset() should
be called before dwc2_get_hwparams() to reset core registers to
default value. Without this the FIFO setting might be incorrect
because calculating FIFO size need power-on value of
GRXFSIZ/GNPTXFSIZ/HPTXFSIZ registers.

This patch could avoid warnning massage like in rk3288 platform:
[ 2.074764] dwc2 ff580000.usb: 256 invalid for
host_perio_tx_fifo_size. Check HW configuration.

Signed-off-by: Yunzhi Li <lyz@xxxxxxxxxxxxxx>

---

drivers/usb/dwc2/core.c | 2 +-
drivers/usb/dwc2/core.h | 1 +
drivers/usb/dwc2/platform.c | 6 ++++++
3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
index c3cc1a7..86d1d65 100644
--- a/drivers/usb/dwc2/core.c
+++ b/drivers/usb/dwc2/core.c
@@ -474,7 +474,7 @@ static void dwc2_init_fs_ls_pclk_sel(struct dwc2_hsotg *hsotg)
* Do core a soft reset of the core. Be careful with this because it
* resets all the internal state machines of the core.
*/
-static int dwc2_core_reset(struct dwc2_hsotg *hsotg)
+int dwc2_core_reset(struct dwc2_hsotg *hsotg)
{
u32 greset;
int count = 0;
diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 0ed87620..5d95aec 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -846,6 +846,7 @@ enum dwc2_halt_status {
* The following functions support initialization of the core driver component
* and the DWC_otg controller
*/
+extern int dwc2_core_reset(struct dwc2_hsotg *hsotg);
extern void dwc2_core_host_init(struct dwc2_hsotg *hsotg);
extern int dwc2_enter_hibernation(struct dwc2_hsotg *hsotg);
extern int dwc2_exit_hibernation(struct dwc2_hsotg *hsotg, bool restore);
diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index 9093530..8d3be4a 100644
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -243,6 +243,12 @@ static int dwc2_driver_probe(struct platform_device *dev)
spin_lock_init(&hsotg->lock);
mutex_init(&hsotg->init_mutex);

+ /*
+ * Reset before dwc2_get_hwparams() then it could get power-on real
+ * reset value form registers.
+ */
+ dwc2_core_reset(hsotg);
+
/* Detect config values from hardware */
retval = dwc2_get_hwparams(hsotg);
if (retval)
--
2.0.0


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