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: Christoph Hellwig <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

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

···
 	.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

···
 	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

···
 		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;
 

drivers/usb/host/ehci-grlib.c

···
 	 * 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

···
 	 * 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-pmcmsp.c

···
 	 * 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-ppc-of.c

···
 	 * 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-ps3.c

···
 	.product_desc		= "PS3 EHCI Host Controller",
 	.hcd_priv_size		= sizeof(struct ehci_hcd),
 	.irq			= ehci_irq,
-	.flags			= HCD_MEMORY | HCD_USB2 | HCD_BH,
+	.flags			= HCD_MEMORY | HCD_DMA | HCD_USB2 | HCD_BH,
 	.reset			= ps3_ehci_hc_reset,
 	.start			= ehci_run,
 	.stop			= ehci_stop,

drivers/usb/host/ehci-sh.c

···
 	 * generic hardware linkage
 	 */
 	.irq				= ehci_irq,
-	.flags				= HCD_USB2 | HCD_MEMORY | HCD_BH,
+	.flags				= HCD_USB2 | HCD_DMA | HCD_MEMORY | HCD_BH,
 
 	/*
 	 * basic lifecycle operations

drivers/usb/host/ehci-xilinx-of.c

···
 	 * 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/fhci-hcd.c

···
 
 	/* generic hardware linkage */
 	.irq = fhci_irq,
-	.flags = HCD_USB11 | HCD_MEMORY,
+	.flags = HCD_DMA | HCD_USB11 | HCD_MEMORY,
 
 	/* basic lifecycle operation */
 	.start = fhci_start,

drivers/usb/host/fotg210-hcd.c

···
 	 * generic hardware linkage
 	 */
 	.irq			= fotg210_irq,
-	.flags			= HCD_MEMORY | HCD_USB2,
+	.flags			= HCD_MEMORY | HCD_DMA | HCD_USB2,
 
 	/*
 	 * basic lifecycle operations

drivers/usb/host/imx21-hcd.c

···
 	.product_desc = "IMX21 USB Host Controller",
 	.hcd_priv_size = sizeof(struct imx21),
 
-	.flags = HCD_USB11,
+	.flags = HCD_DMA | HCD_USB11,
 	.irq = imx21_irq,
 
 	.reset = imx21_hc_reset,

drivers/usb/host/isp116x-hcd.c

···
 	irq = ires->start;
 	irqflags = ires->flags & IRQF_TRIGGER_MASK;
 
-	if (pdev->dev.dma_mask) {
-		DBG("DMA not supported\n");
-		ret = -EINVAL;
-		goto err1;
-	}
-
 	if (!request_mem_region(addr->start, 2, hcd_name)) {
 		ret = -EBUSY;
 		goto err1;

drivers/usb/host/isp1362-hcd.c

···
 	if (pdev->num_resources < 3)
 		return -ENODEV;
 
-	if (pdev->dev.dma_mask) {
-		DBG(1, "won't do DMA");
-		return -ENODEV;
-	}
-
 	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 	if (!irq_res)
 		return -ENODEV;

drivers/usb/host/ohci-hcd.c

···
 	 * generic hardware linkage
 	*/
 	.irq =                  ohci_irq,
-	.flags =                HCD_MEMORY | HCD_USB11,
+	.flags =                HCD_MEMORY | HCD_DMA | HCD_USB11,
 
 	/*
 	* basic lifecycle operations

drivers/usb/host/ohci-ppc-of.c

···
 	 * generic hardware linkage
 	 */
 	.irq =			ohci_irq,
-	.flags =		HCD_USB11 | HCD_MEMORY,
+	.flags =		HCD_USB11 | HCD_DMA | HCD_MEMORY,
 
 	/*
 	 * basic lifecycle operations

drivers/usb/host/ohci-ps3.c

···
 	.product_desc		= "PS3 OHCI Host Controller",
 	.hcd_priv_size		= sizeof(struct ohci_hcd),
 	.irq			= ohci_irq,
-	.flags			= HCD_MEMORY | HCD_USB11,
+	.flags			= HCD_MEMORY | HCD_DMA | HCD_USB11,
 	.reset			= ps3_ohci_hc_reset,
 	.start			= ps3_ohci_hc_start,
 	.stop			= ohci_stop,

drivers/usb/host/ohci-sa1111.c

···
 	 * generic hardware linkage
 	 */
 	.irq =			ohci_irq,
-	.flags =		HCD_USB11 | HCD_MEMORY,
+	.flags =		HCD_USB11 | HCD_DMA | HCD_MEMORY,
 
 	/*
 	 * basic lifecycle operations

drivers/usb/host/ohci-sm501.c

···
 	 * generic hardware linkage
 	 */
 	.irq =			ohci_irq,
-	.flags =		HCD_USB11 | HCD_MEMORY,
+	.flags =		HCD_USB11 | HCD_DMA | HCD_MEMORY,
 
 	/*
 	 * basic lifecycle operations

drivers/usb/host/ohci-tmio.c

···
 
 	/* generic hardware linkage */
 	.irq =			ohci_irq,
-	.flags =		HCD_USB11 | HCD_MEMORY,
+	.flags =		HCD_USB11 | HCD_DMA | HCD_MEMORY,
 
 	/* basic lifecycle operations */
 	.start =		ohci_tmio_start,

drivers/usb/host/oxu210hp-hcd.c

···
 	INIT_LIST_HEAD(&oxu->urb_list);
 	oxu->urb_len = 0;
 
-	/* FIMXE */
-	hcd->self.controller->dma_mask = NULL;
-
 	if (oxu->is_otg) {
 		oxu->caps = hcd->regs + OXU_OTG_CAP_OFFSET;
 		oxu->regs = hcd->regs + OXU_OTG_CAP_OFFSET + \

drivers/usb/host/r8a66597-hcd.c

···
 	if (usb_disabled())
 		return -ENODEV;
 
-	if (pdev->dev.dma_mask) {
-		ret = -EINVAL;
-		dev_err(&pdev->dev, "dma not supported\n");
-		goto clean_up;
-	}
-
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res) {
 		ret = -ENODEV;

drivers/usb/host/sl811-hcd.c

···
 	irq = ires->start;
 	irqflags = ires->flags & IRQF_TRIGGER_MASK;
 
-	/* refuse to confuse usbcore */
-	if (dev->dev.dma_mask) {
-		dev_dbg(&dev->dev, "no we won't dma\n");
-		return -EINVAL;
-	}
-
 	/* the chip may be wired for either kind of addressing */
 	addr = platform_get_resource(dev, IORESOURCE_MEM, 0);
 	data = platform_get_resource(dev, IORESOURCE_MEM, 1);

drivers/usb/host/u132-hcd.c

···
 	retval = ftdi_read_pcimem(pdev, roothub.a, &rh_a);
 	if (retval)
 		return retval;
-	if (pdev->dev.dma_mask)
-		return -EINVAL;
 
 	hcd = usb_create_hcd(&u132_hc_driver, &pdev->dev, dev_name(&pdev->dev));
 	if (!hcd) {

drivers/usb/host/uhci-grlib.c

···
 
 	/* Generic hardware linkage */
 	.irq =			uhci_irq,
-	.flags =		HCD_MEMORY | HCD_USB11,
+	.flags =		HCD_MEMORY | HCD_DMA | HCD_USB11,
 
 	/* Basic lifecycle operations */
 	.reset =		uhci_grlib_init,

drivers/usb/host/uhci-pci.c

···
 
 	/* Generic hardware linkage */
 	.irq =			uhci_irq,
-	.flags =		HCD_USB11,
+	.flags =		HCD_DMA | HCD_USB11,
 
 	/* Basic lifecycle operations */
 	.reset =		uhci_pci_init,

drivers/usb/host/uhci-platform.c

···
 
 	/* Generic hardware linkage */
 	.irq =			uhci_irq,
-	.flags =		HCD_MEMORY | HCD_USB11,
+	.flags =		HCD_MEMORY | HCD_DMA | HCD_USB11,
 
 	/* Basic lifecycle operations */
 	.reset =		uhci_platform_init,

drivers/usb/host/xhci.c

···
 	 * generic hardware linkage
 	 */
 	.irq =			xhci_irq,
-	.flags =		HCD_MEMORY | HCD_USB3 | HCD_SHARED,
+	.flags =		HCD_MEMORY | HCD_DMA | HCD_USB3 | HCD_SHARED,
 
 	/*
 	 * basic lifecycle operations

drivers/usb/isp1760/isp1760-core.c

···
 	    (!IS_ENABLED(CONFIG_USB_ISP1761_UDC) || udc_disabled))
 		return -ENODEV;
 
-	/* prevent usb-core allocating DMA pages */
-	dev->dma_mask = NULL;
-
 	isp = devm_kzalloc(dev, sizeof(*isp), GFP_KERNEL);
 	if (!isp)
 		return -ENOMEM;

drivers/usb/isp1760/isp1760-if.c

···
 
 	pci_set_master(dev);
 
-	dev->dev.dma_mask = NULL;
 	ret = isp1760_register(&dev->resource[3], dev->irq, 0, &dev->dev,
 			       devflags);
 	if (ret < 0)

drivers/usb/musb/musb_host.c

···
 	.description		= "musb-hcd",
 	.product_desc		= "MUSB HDRC host driver",
 	.hcd_priv_size		= sizeof(struct musb *),
-	.flags			= HCD_USB2 | HCD_MEMORY,
+	.flags			= HCD_USB2 | HCD_DMA | HCD_MEMORY,
 
 	/* not using irq handler or reset hooks from usbcore, since
 	 * those must be shared with peripheral code for OTG configs

drivers/usb/renesas_usbhs/mod_host.c

···
 	/*
 	 * generic hardware linkage
 	 */
-	.flags =		HCD_USB2,
+	.flags =		HCD_DMA | HCD_USB2,
 
 	.start =		usbhsh_host_start,
 	.stop =			usbhsh_host_stop,

include/linux/usb.h

···
 	struct device *sysdev;		/* as seen from firmware or bus */
 	int busnum;			/* Bus number (in order of reg) */
 	const char *bus_name;		/* stable id (PCI slot_name etc) */
-	u8 uses_dma;			/* Does the host controller use DMA? */
 	u8 uses_pio_for_control;	/*
 					 * Does the host controller use PIO
 					 * for control transfers?

include/linux/usb/hcd.h

···
 
 	int	flags;
 #define	HCD_MEMORY	0x0001		/* HC regs use memory (else I/O) */
+#define	HCD_DMA		0x0002		/* HC uses DMA */
 #define	HCD_SHARED	0x0004		/* Two (or more) usb_hcds share HW */
 #define	HCD_USB11	0x0010		/* USB 1.1 */
 #define	HCD_USB2	0x0020		/* USB 2.0 */
···
 	return hcd->high_prio_bh.completing_ep == ep;
 }
 
-#define hcd_uses_dma(hcd) \
-	(IS_ENABLED(CONFIG_HAS_DMA) && (hcd)->self.uses_dma)
+static inline bool hcd_uses_dma(struct usb_hcd *hcd)
+{
+	return IS_ENABLED(CONFIG_HAS_DMA) && (hcd->driver->flags & HCD_DMA);
+}
 
 extern int usb_hcd_link_urb_to_ep(struct usb_hcd *hcd, struct urb *urb);
 extern int usb_hcd_check_unlink_urb(struct usb_hcd *hcd, struct urb *urb,