[PATCH 1/3] usb: dwc2: set ahbcfg parameter for STM32MP15 OTG HS and FS

[Amelie Delaunay]

STM32MP15 ahbcfg register default value sets Burst length/type (HBSTLEN)
to Single (32-bit accesses on AHB), which is not recommended, according
to STM32MP157 Reference manual [1].
This patch sets Burst length/type (HBSTLEN) so that bus transactions
target 16x32 bit accesses. This improves OTG controller performance.

[1] https://www.st.com/resource/en/reference_manual/dm00327659.pdf, p.3149

Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxx>
---
 drivers/usb/dwc2/params.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/dwc2/params.c b/drivers/usb/dwc2/params.c
index 267543c3dc38..0df693319f0a 100644
--- a/drivers/usb/dwc2/params.c
+++ b/drivers/usb/dwc2/params.c
@@ -177,6 +177,7 @@ static void dwc2_set_stm32mp15_fsotg_params(struct dwc2_hsotg *hsotg)
 	p->i2c_enable = false;
 	p->activate_stm_fs_transceiver = true;
 	p->activate_stm_id_vb_detection = true;
+	p->ahbcfg = GAHBCFG_HBSTLEN_INCR16 << GAHBCFG_HBSTLEN_SHIFT;
 	p->power_down = DWC2_POWER_DOWN_PARAM_NONE;
 }
 
@@ -189,6 +190,7 @@ static void dwc2_set_stm32mp15_hsotg_params(struct dwc2_hsotg *hsotg)
 	p->host_rx_fifo_size = 440;
 	p->host_nperio_tx_fifo_size = 256;
 	p->host_perio_tx_fifo_size = 256;
+	p->ahbcfg = GAHBCFG_HBSTLEN_INCR16 << GAHBCFG_HBSTLEN_SHIFT;
 	p->power_down = DWC2_POWER_DOWN_PARAM_NONE;
 }
 
-- 
2.17.1