2020-11-23 09:04:52

by Amelie Delaunay

Subject: [PATCH 1/3] 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

Signed-off-by: Amelie Delaunay <[email protected]>
---
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

2020-11-30 06:19:24

by Minas Harutyunyan

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

On 11/23/2020 1:01 PM, Amelie Delaunay wrote:
> 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://urldefense.com/v3/__https://www.st.com/resource/en/reference_manual/dm00327659.pdf__;!!A4F2R9G_pg!J1HTs3kobvYfS453htoIdnxhej4_os5Y5xwMfRtfhptE_QSeVw3O1mozY-v4AvE$ , p.3149
>
> Signed-off-by: Amelie Delaunay <[email protected]>

Acked-by: Minas Harutyunyan <[email protected]>

> ---
> 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;
> }
>
>