usb: dwc2: set ahbcfg parameter for STM32MP15 OTG HS and FS

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

Acked-by: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/20210105094855.30763-2-amelie.delaunay@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/dwc2/params.c b/drivers/usb/dwc2/params.c
index 267543c..0df6933 100644 (file)
--- 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;
 }