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Message-ID: <d4d25747-83d4-a8e7-7968-caf3b14a844c@quicinc.com>
Date:   Mon, 27 Nov 2023 14:28:45 +0530
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Subject: Re: [PATCH] usb: dwc3: core: Add support for
 XHCI_SG_TRB_CACHE_SIZE_QUIRK
Content-Language: en-US
To:     Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Mathias Nyman <mathias.nyman@intel.com>
CC:     <linux-kernel@vger.kernel.org>, <linux-usb@vger.kernel.org>,
        <stable@vger.kernel.org>
References: <20231121135936.1669167-1-quic_prashk@quicinc.com>
From:   Prashanth K <quic_prashk@quicinc.com>
In-Reply-To: <20231121135936.1669167-1-quic_prashk@quicinc.com>
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On 21-11-23 07:29 pm, Prashanth K wrote:
>   drivers/usb/dwc3/host.c | 10 ++++++++++
>   1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
> index 61f57fe5bb78..ee3b667a88b2 100644
> --- a/drivers/usb/dwc3/host.c
> +++ b/drivers/usb/dwc3/host.c
> @@ -11,6 +11,7 @@
>   #include <linux/of.h>
>   #include <linux/platform_device.h>
>   
> +#include "../host/xhci-plat.h"
>   #include "core.h"
>   
>   static void dwc3_host_fill_xhci_irq_res(struct dwc3 *dwc,
> @@ -63,6 +64,7 @@ int dwc3_host_init(struct dwc3 *dwc)
>   {
>   	struct property_entry	props[4];
>   	struct platform_device	*xhci;
> +	struct xhci_plat_priv   dwc3_xhci_plat_priv;
>   	int			ret, irq;
>   	int			prop_idx = 0;
>   
> @@ -87,6 +89,14 @@ int dwc3_host_init(struct dwc3 *dwc)
>   		goto err;
>   	}
>   
> +	memset(&dwc3_xhci_plat_priv, 0, sizeof(struct xhci_plat_priv));
> +
> +	dwc3_xhci_plat_priv.quirks |= XHCI_SG_TRB_CACHE_SIZE_QUIRK;
> +	ret = platform_device_add_data(xhci, &dwc3_xhci_plat_priv,
> +					sizeof(dwc3_xhci_plat_priv));
> +	if (ret)
> +		goto err;
> +
>   	memset(props, 0, sizeof(struct property_entry) * ARRAY_SIZE(props));
>   
>   	if (dwc->usb3_lpm_capable)

Is the above approach acceptable? I'm not sure if accessing xhci-plat's 
structure from dwc3 is a recommended way. If not, then can we go ahead 
with the following approach where we add a property to XHCI SW node.


--- a/drivers/usb/dwc3/host.c
+++ b/drivers/usb/dwc3/host.c
@@ -89,6 +89,8 @@ int dwc3_host_init(struct dwc3 *dwc)

         memset(props, 0, sizeof(struct property_entry) * 
ARRAY_SIZE(props));

+       props[prop_idx++] = 
PROPERTY_ENTRY_BOOL("xhci-sg-trb-cache-size-quirk");
+
         if (dwc->usb3_lpm_capable)
                 props[prop_idx++] = 
PROPERTY_ENTRY_BOOL("usb3-lpm-capable");


--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -323,6 +323,9 @@ static int xhci_plat_probe(struct platform_device *pdev)
                 if (device_property_read_bool(tmpdev, 
"quirk-broken-port-ped"))
                         xhci->quirks |= XHCI_BROKEN_PORT_PED;

+               if (device_property_read_bool(tmpdev, 
"xhci-sg-trb-cache-size-quirk"))
+                       xhci->quirks |= XHCI_SG_TRB_CACHE_SIZE_QUIRK;
+
                 device_property_read_u32(tmpdev, "imod-interval-ns",
                                          &xhci->imod_interval);
         }


Regards,
Prashanth K