Commit 7b81cb6b authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Greg Kroah-Hartman
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usb: add a HCD_DMA flag instead of guestimating DMA capabilities 



The usb core is the only major place in the kernel that checks for
a non-NULL device dma_mask to see if a device is DMA capable.  This
is generally a bad idea, as all major busses always set up a DMA mask,
even if the device is not DMA capable - in fact bus layers like PCI
can't even know if a device is DMA capable at enumeration time.  This
leads to lots of workaround in HCD drivers, and also prevented us from
setting up a DMA mask for platform devices by default last time we
tried.

Replace this guess with an explicit HCD_DMA that is set by drivers that
appear to have DMA support.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20190816062435.881-4-hch@lst.de


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 0709831a

drivers/staging/octeon-usb/octeon-hcd.c

+1 −1
Original line number Diff line number Diff line
@@ -3512,7 +3512,7 @@ static const struct hc_driver octeon_hc_driver = { 
	.product_desc		= "Octeon Host Controller",

	.hcd_priv_size		= sizeof(struct octeon_hcd),

	.irq			= octeon_usb_irq,

	.flags			= HCD_MEMORY | HCD_USB2,

	.flags			= HCD_MEMORY | HCD_DMA | HCD_USB2,

	.start			= octeon_usb_start,

	.stop			= octeon_usb_stop,

	.urb_enqueue		= octeon_usb_urb_enqueue,

drivers/usb/core/hcd.c

+0 −1
Original line number Diff line number Diff line
@@ -2454,7 +2454,6 @@ struct usb_hcd *__usb_create_hcd(const struct hc_driver *driver, 
	hcd->self.controller = dev;

	hcd->self.sysdev = sysdev;

	hcd->self.bus_name = bus_name;

	hcd->self.uses_dma = (sysdev->dma_mask != NULL);



	timer_setup(&hcd->rh_timer, rh_timer_func, 0);

#ifdef CONFIG_PM

drivers/usb/dwc2/hcd.c

+3 −3
Original line number Diff line number Diff line
@@ -5062,13 +5062,13 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg) 
		dwc2_hc_driver.reset_device = dwc2_reset_device;

	}



	if (hsotg->params.host_dma)

		dwc2_hc_driver.flags |= HCD_DMA;



	hcd = usb_create_hcd(&dwc2_hc_driver, hsotg->dev, dev_name(hsotg->dev));

	if (!hcd)

		goto error1;



	if (!hsotg->params.host_dma)

		hcd->self.uses_dma = 0;



	hcd->has_tt = 1;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

drivers/usb/host/ehci-grlib.c

+1 −1
Original line number Diff line number Diff line
@@ -30,7 +30,7 @@ static const struct hc_driver ehci_grlib_hc_driver = { 
	 * generic hardware linkage

	 */

	.irq			= ehci_irq,

	.flags			= HCD_MEMORY | HCD_USB2 | HCD_BH,

	.flags			= HCD_MEMORY | HCD_DMA | HCD_USB2 | HCD_BH,



	/*

	 * basic lifecycle operations

drivers/usb/host/ehci-hcd.c

+1 −1
Original line number Diff line number Diff line
@@ -1193,7 +1193,7 @@ static const struct hc_driver ehci_hc_driver = { 
	 * generic hardware linkage

	 */

	.irq =			ehci_irq,

	.flags =		HCD_MEMORY | HCD_USB2 | HCD_BH,

	.flags =		HCD_MEMORY | HCD_DMA | HCD_USB2 | HCD_BH,



	/*

	 * basic lifecycle operations

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