linux-stable/drivers/usb/host/ohci-sa1111.c
Arnd Bergmann 9ba26f5cec ARM: sa1100/assabet: move dmabounce hack to ohci driver
The sa1111 platform is one of the two remaining users of the old Arm
specific "dmabounce" code, which is an earlier implementation of the
generic swiotlb.

Linus Walleij submitted a patch that removes dmabounce support from
the ixp4xx, and I had a look at the other user, which is the sa1111
companion chip.

Looking at how dmabounce is used, I could narrow it down to one driver
one three machines:

 - dmabounce is only initialized on assabet/neponset, jornada720 and
   badge4, which are the platforms that have an sa1111 and support
   DMA on it.

 - All three of these suffer from "erratum #7" that requires only
   doing DMA to half the memory sections based on one of the address
   lines, in addition, the neponset also can't DMA to the RAM that
   is connected to sa1111 itself.

 - the pxa lubbock machine also has sa1111, but does not support DMA
   on it and does not set dmabounce.

 - only the OHCI and audio devices on sa1111 support DMA, but as
   there is no audio driver for this hardware, only OHCI remains.

In the OHCI code, I noticed that two other platforms already have
a local bounce buffer support in the form of the "local_mem"
allocator. Specifically, TMIO and SM501 use this on a few other ARM
boards with 16KB or 128KB of local SRAM that can be accessed from the
OHCI and from the CPU.

While this is not the same problem as on sa1111, I could not find a
reason why we can't re-use the existing implementation but replace the
physical SRAM address mapping with a locally allocated DMA buffer.

There are two main downsides:

 - rather than using a dynamically sized pool, this buffer needs
   to be allocated at probe time using a fixed size. Without
   having any idea of what it should be, I picked a size of
   64KB, which is between what the other two OHCI front-ends use
   in their SRAM. If anyone has a better idea what that size
   is reasonable, this can be trivially changed.

 - Previously, only USB transfers to unaddressable memory needed
   to go through the bounce buffer, now all of them do, which may
   impact runtime performance for USB endpoints that do a lot of
   transfers.

On the upside, the local_mem support uses write-combining buffers,
which should be a bit faster for transfers to the device compared to
normal uncached coherent memory as used in dmabounce.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Cc: linux-usb@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2022-07-07 18:18:47 +02:00

294 lines
7.4 KiB
C

// SPDX-License-Identifier: GPL-1.0+
/*
* OHCI HCD (Host Controller Driver) for USB.
*
* (C) Copyright 1999 Roman Weissgaerber <weissg@vienna.at>
* (C) Copyright 2000-2002 David Brownell <dbrownell@users.sourceforge.net>
* (C) Copyright 2002 Hewlett-Packard Company
*
* SA1111 Bus Glue
*
* Written by Christopher Hoover <ch@hpl.hp.com>
* Based on fragments of previous driver by Russell King et al.
*
* This file is licenced under the GPL.
*/
#include <asm/mach-types.h>
#include <asm/hardware/sa1111.h>
#ifndef CONFIG_SA1111
#error "This file is SA-1111 bus glue. CONFIG_SA1111 must be defined."
#endif
#define USB_STATUS 0x0118
#define USB_RESET 0x011c
#define USB_IRQTEST 0x0120
#define USB_RESET_FORCEIFRESET (1 << 0)
#define USB_RESET_FORCEHCRESET (1 << 1)
#define USB_RESET_CLKGENRESET (1 << 2)
#define USB_RESET_SIMSCALEDOWN (1 << 3)
#define USB_RESET_USBINTTEST (1 << 4)
#define USB_RESET_SLEEPSTBYEN (1 << 5)
#define USB_RESET_PWRSENSELOW (1 << 6)
#define USB_RESET_PWRCTRLLOW (1 << 7)
#define USB_STATUS_IRQHCIRMTWKUP (1 << 7)
#define USB_STATUS_IRQHCIBUFFACC (1 << 8)
#define USB_STATUS_NIRQHCIM (1 << 9)
#define USB_STATUS_NHCIMFCLR (1 << 10)
#define USB_STATUS_USBPWRSENSE (1 << 11)
#if 0
static void dump_hci_status(struct usb_hcd *hcd, const char *label)
{
unsigned long status = readl_relaxed(hcd->regs + USB_STATUS);
printk(KERN_DEBUG "%s USB_STATUS = { %s%s%s%s%s}\n", label,
((status & USB_STATUS_IRQHCIRMTWKUP) ? "IRQHCIRMTWKUP " : ""),
((status & USB_STATUS_IRQHCIBUFFACC) ? "IRQHCIBUFFACC " : ""),
((status & USB_STATUS_NIRQHCIM) ? "" : "IRQHCIM "),
((status & USB_STATUS_NHCIMFCLR) ? "" : "HCIMFCLR "),
((status & USB_STATUS_USBPWRSENSE) ? "USBPWRSENSE " : ""));
}
#endif
static int ohci_sa1111_reset(struct usb_hcd *hcd)
{
struct ohci_hcd *ohci = hcd_to_ohci(hcd);
ohci_hcd_init(ohci);
return ohci_init(ohci);
}
static int ohci_sa1111_start(struct usb_hcd *hcd)
{
struct ohci_hcd *ohci = hcd_to_ohci(hcd);
int ret;
ret = ohci_run(ohci);
if (ret < 0) {
ohci_err(ohci, "can't start\n");
ohci_stop(hcd);
}
return ret;
}
static const struct hc_driver ohci_sa1111_hc_driver = {
.description = hcd_name,
.product_desc = "SA-1111 OHCI",
.hcd_priv_size = sizeof(struct ohci_hcd),
/*
* generic hardware linkage
*/
.irq = ohci_irq,
.flags = HCD_USB11 | HCD_DMA | HCD_MEMORY,
/*
* basic lifecycle operations
*/
.reset = ohci_sa1111_reset,
.start = ohci_sa1111_start,
.stop = ohci_stop,
.shutdown = ohci_shutdown,
/*
* managing i/o requests and associated device resources
*/
.urb_enqueue = ohci_urb_enqueue,
.urb_dequeue = ohci_urb_dequeue,
.endpoint_disable = ohci_endpoint_disable,
/*
* scheduling support
*/
.get_frame_number = ohci_get_frame,
/*
* root hub support
*/
.hub_status_data = ohci_hub_status_data,
.hub_control = ohci_hub_control,
#ifdef CONFIG_PM
.bus_suspend = ohci_bus_suspend,
.bus_resume = ohci_bus_resume,
#endif
.start_port_reset = ohci_start_port_reset,
};
static int sa1111_start_hc(struct sa1111_dev *dev)
{
unsigned int usb_rst = 0;
int ret;
dev_dbg(&dev->dev, "starting SA-1111 OHCI USB Controller\n");
if (machine_is_xp860() ||
machine_is_assabet() ||
machine_is_pfs168() ||
machine_is_badge4())
usb_rst = USB_RESET_PWRSENSELOW | USB_RESET_PWRCTRLLOW;
/*
* Configure the power sense and control lines. Place the USB
* host controller in reset.
*/
writel_relaxed(usb_rst | USB_RESET_FORCEIFRESET | USB_RESET_FORCEHCRESET,
dev->mapbase + USB_RESET);
/*
* Now, carefully enable the USB clock, and take
* the USB host controller out of reset.
*/
ret = sa1111_enable_device(dev);
if (ret == 0) {
udelay(11);
writel_relaxed(usb_rst, dev->mapbase + USB_RESET);
}
return ret;
}
static void sa1111_stop_hc(struct sa1111_dev *dev)
{
unsigned int usb_rst;
dev_dbg(&dev->dev, "stopping SA-1111 OHCI USB Controller\n");
/*
* Put the USB host controller into reset.
*/
usb_rst = readl_relaxed(dev->mapbase + USB_RESET);
writel_relaxed(usb_rst | USB_RESET_FORCEIFRESET | USB_RESET_FORCEHCRESET,
dev->mapbase + USB_RESET);
/*
* Stop the USB clock.
*/
sa1111_disable_device(dev);
}
/**
* ohci_hcd_sa1111_probe - initialize SA-1111-based HCDs
*
* Allocates basic resources for this USB host controller, and
* then invokes the start() method for the HCD associated with it.
*/
static int ohci_hcd_sa1111_probe(struct sa1111_dev *dev)
{
struct usb_hcd *hcd;
int ret, irq;
if (usb_disabled())
return -ENODEV;
/*
* We don't call dma_set_mask_and_coherent() here because the
* DMA mask has already been appropraitely setup by the core
* SA-1111 bus code (which includes bug workarounds.)
*/
hcd = usb_create_hcd(&ohci_sa1111_hc_driver, &dev->dev, "sa1111");
if (!hcd)
return -ENOMEM;
hcd->rsrc_start = dev->res.start;
hcd->rsrc_len = resource_size(&dev->res);
irq = sa1111_get_irq(dev, 1);
if (irq <= 0) {
ret = irq ? : -ENXIO;
goto err1;
}
/*
* According to the "Intel StrongARM SA-1111 Microprocessor Companion
* Chip Specification Update" (June 2000), erratum #7, there is a
* significant bug in the SA1111 SDRAM shared memory controller. If
* an access to a region of memory above 1MB relative to the bank base,
* it is important that address bit 10 _NOT_ be asserted. Depending
* on the configuration of the RAM, bit 10 may correspond to one
* of several different (processor-relative) address bits.
*
* Section 4.6 of the "Intel StrongARM SA-1111 Development Module
* User's Guide" mentions that jumpers R51 and R52 control the
* target of SA-1111 DMA (either SDRAM bank 0 on Assabet, or
* SDRAM bank 1 on Neponset). The default configuration selects
* Assabet, so any address in bank 1 is necessarily invalid.
*
* As a workaround, use a bounce buffer in addressable memory
* as local_mem, relying on ZONE_DMA to provide an area that
* fits within the above constraints.
*
* SZ_64K is an estimate for what size this might need.
*/
ret = usb_hcd_setup_local_mem(hcd, 0, 0, SZ_64K);
if (ret)
goto err1;
if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len, hcd_name)) {
dev_dbg(&dev->dev, "request_mem_region failed\n");
ret = -EBUSY;
goto err1;
}
hcd->regs = dev->mapbase;
ret = sa1111_start_hc(dev);
if (ret)
goto err2;
ret = usb_add_hcd(hcd, irq, 0);
if (ret == 0) {
device_wakeup_enable(hcd->self.controller);
return ret;
}
sa1111_stop_hc(dev);
err2:
release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
err1:
usb_put_hcd(hcd);
return ret;
}
/**
* ohci_hcd_sa1111_remove - shutdown processing for SA-1111-based HCDs
* @dev: USB Host Controller being removed
*
* Reverses the effect of ohci_hcd_sa1111_probe(), first invoking
* the HCD's stop() method.
*/
static void ohci_hcd_sa1111_remove(struct sa1111_dev *dev)
{
struct usb_hcd *hcd = sa1111_get_drvdata(dev);
usb_remove_hcd(hcd);
sa1111_stop_hc(dev);
release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
usb_put_hcd(hcd);
}
static void ohci_hcd_sa1111_shutdown(struct device *_dev)
{
struct sa1111_dev *dev = to_sa1111_device(_dev);
struct usb_hcd *hcd = sa1111_get_drvdata(dev);
if (test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)) {
hcd->driver->shutdown(hcd);
sa1111_stop_hc(dev);
}
}
static struct sa1111_driver ohci_hcd_sa1111_driver = {
.drv = {
.name = "sa1111-ohci",
.owner = THIS_MODULE,
.shutdown = ohci_hcd_sa1111_shutdown,
},
.devid = SA1111_DEVID_USB,
.probe = ohci_hcd_sa1111_probe,
.remove = ohci_hcd_sa1111_remove,
};