From: mathias.nyman@linux•intel.com (Mathias Nyman)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v7 1/2] usb: make xhci platform driver use 64 bit or 32 bit DMA
Date: Tue, 01 Sep 2015 14:54:17 +0300 [thread overview]
Message-ID: <55E591E9.60008@linux.intel.com> (raw)
In-Reply-To: <CADaLNDnPaeHcMjywsuQ4oiUpWsNpStshdKVtW=tuUorrcQkZ=g@mail.gmail.com>
On 31.08.2015 21:58, Duc Dang wrote:
> On Thu, Aug 20, 2015 at 12:38 PM, Duc Dang <dhdang@apm•com> wrote:
>> The xhci platform driver needs to work on systems that
>> either only support 64-bit DMA or only support 32-bit DMA.
>> Attempt to set a coherent dma mask for 64-bit DMA, and
>> attempt again with 32-bit DMA if that fails.
>>
>> [dhdang: regenerate the patch over 4.2-rc5 and address new comments]
>> Signed-off-by: Mark Langsdorf <mlangsdo@redhat•com>
>> Tested-by: Mark Salter <msalter@redhat•com>
>> Signed-off-by: Duc Dang <dhdang@apm•com>
>>
>> ---
>> Changes from v6:
>> -Add WARN_ON if dma_mask is NULL
>> -Use dma_coerce_mask_and_coherent to assign
>> dma_mask and coherent_dma_mask
>>
>> Changes from v5:
>> -Change comment
>> -Assign dma_mask to coherent_dma_mask if dma_mask is NULL
>> to make sure dma_set_mask_and_coherent does not fail prematurely.
>>
>> Changes from v4:
>> -None
>>
>> Changes from v3:
>> -Re-generate the patch over 4.2-rc5
>> -No code change.
>>
>> Changes from v2:
>> -None
>>
>> Changes from v1:
>> -Consolidated to use dma_set_mask_and_coherent
>> -Got rid of the check against sizeof(dma_addr_t)
>>
>> drivers/usb/host/xhci-plat.c | 21 +++++++++++++--------
>> 1 file changed, 13 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
>> index 890ad9d..e4c7f9d 100644
>> --- a/drivers/usb/host/xhci-plat.c
>> +++ b/drivers/usb/host/xhci-plat.c
>> @@ -93,14 +93,19 @@ static int xhci_plat_probe(struct platform_device *pdev)
>> if (irq < 0)
>> return -ENODEV;
>>
>> - /* Initialize dma_mask and coherent_dma_mask to 32-bits */
>> - ret = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
>> - if (ret)
>> - return ret;
>> - if (!pdev->dev.dma_mask)
>> - pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
>> - else
>> - dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
>> + /* Throw a waring if broken platform code didn't initialize dma_mask */
>> + WARN_ON(!pdev->dev.dma_mask);
>> + /*
>> + * Try setting dma_mask and coherent_dma_mask to 64 bits,
>> + * then try 32 bits
>> + */
>> + ret = dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
>> + if (ret) {
>> + ret = dma_coerce_mask_and_coherent(&pdev->dev,
>> + DMA_BIT_MASK(32));
>> + if (ret)
>> + return ret;
>> + }
>>
>> hcd = usb_create_hcd(driver, &pdev->dev, dev_name(&pdev->dev));
>> if (!hcd)
>> --
>> 1.9.1
>>
>
> Hi Greg, Arnd, Russell,
>
> Do you have any more comment about this patch set?
>
I'm not sure I fully understand why we need to try the 64 bit DMA mask in platform probe.
As I understood it we just want to have some DMA mask set before calling usb_create_hcd()
to make sure USB core gets the "uses_dma" flag set and dma_set_mask() won't fail because of
missing dev->dma_mask.
The correct DMA mask is set later in xhci_gen_setup()
We also need to make sure the controller supports 64bit addressing capability before setting a 64 bit DMA mask.
(bit 0 in HCCPARAMS)
So for platform devices it goes look go this:
xhci_plat_probe()
usb_create_hcd()
usb_create_shared_hcd()
hcd->self.uses_dma = (dev->dma_mask != NULL);
usb_add_hcd()
hcd->driver->reset() (.reset = xhci_plat_setup)
xhci_plat_setup()
xhci_gen_setup()
if (HCC_64BIT_ADDR(xhci->hcc_params) && !dma_set_mask(dev, DMA_BIT_MASK(64))) {
xhci_dbg(xhci, "Enabling 64-bit DMA addresses.\n");
dma_set_coherent_mask(dev, DMA_BIT_MASK(64));
}
or do we end up with dev->dma_mask = NULL on 64-bit DMA only after trying to set it to 32 in xhci_plat_probe(),
and thus also failing the dma_set_mask() in xhci_gen_setup()?
-Mathias
next prev parent reply other threads:[~2015-09-01 11:54 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CADaLNDkeOP+gBw0qdSDha551w+w+q4ry9-EevDw5giyiQGdnqA@mail.gmail.com>
2015-08-08 1:03 ` [PATCH v4 1/2] usb: make xhci platform driver use 64 bit or 32 bit DMA Duc Dang
2015-08-08 1:03 ` [PATCH v4 2/2] usb: Add support for ACPI identification to xhci-platform Duc Dang
2015-08-08 1:29 ` Greg KH
2015-08-08 2:40 ` Duc Dang
2015-08-08 3:18 ` [PATCH v5 1/2] usb: make xhci platform driver use 64 bit or 32 bit DMA Duc Dang
2015-08-08 3:18 ` [PATCH v5 2/2] usb: Add support for ACPI identification to xhci-platform Duc Dang
2015-08-08 9:22 ` [PATCH v5 1/2] usb: make xhci platform driver use 64 bit or 32 bit DMA Russell King - ARM Linux
2015-08-08 20:31 ` Duc Dang
2015-08-15 20:05 ` Arnd Bergmann
2015-08-19 21:28 ` Duc Dang
2015-08-20 13:09 ` Arnd Bergmann
2015-08-20 19:38 ` [PATCH v7 " Duc Dang
2015-08-20 19:38 ` [PATCH v7 2/2] usb: Add support for ACPI identification to xhci-platform Duc Dang
2015-08-31 18:58 ` [PATCH v7 1/2] usb: make xhci platform driver use 64 bit or 32 bit DMA Duc Dang
2015-09-01 11:54 ` Mathias Nyman [this message]
2015-09-01 12:07 ` Russell King - ARM Linux
2015-09-10 20:53 ` Duc Dang
2015-09-17 18:19 ` [PATCH v8 0/3] usb: xhci-platform: Configure 64-bit DMA mask if the platform is capable Duc Dang
2015-09-17 18:19 ` [PATCH v8 1/3] usb: make xhci platform driver use 64 bit or 32 bit DMA Duc Dang
2015-09-17 19:51 ` Arnd Bergmann
2015-09-17 20:29 ` Duc Dang
2015-09-17 18:19 ` [PATCH v8 2/3] usb: Add support for ACPI identification to xhci-platform Duc Dang
2015-09-17 18:19 ` [PATCH v8 3/3] usb: xhci: configure 32-bit DMA if the controller does not support 64-bit DMA Duc Dang
2015-09-30 21:24 ` [PATCH v8 0/3] usb: xhci-platform: Configure 64-bit DMA mask if the platform is capable Duc Dang
2015-10-04 9:10 ` Greg KH
2015-10-07 13:20 ` Mathias Nyman
2015-08-10 7:37 ` [PATCH v6 1/2] usb: make xhci platform driver use 64 bit or 32 bit DMA Duc Dang
2015-08-10 7:37 ` [PATCH v6 2/2] usb: Add support for ACPI identification to xhci-platform Duc Dang
2015-08-08 5:43 ` [PATCH v4 " Javier Martinez Canillas
2015-08-08 15:37 ` Greg KH
2015-08-08 16:45 ` Duc Dang
2015-08-08 21:05 ` Javier Martinez Canillas
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