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@xxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Laurentiu Tudor <laurentiu.tudor@xxxxxxx>
Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Cc: linux-usb@xxxxxxxxxxxxxxx
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
I don't have this hardware, so the patch is not tested at all.
---
arch/arm/common/Kconfig | 1 -
arch/arm/common/sa1111.c | 64 ----------------------------------
drivers/usb/core/hcd.c | 17 +++++++--
drivers/usb/host/ohci-sa1111.c | 16 +++++++++
4 files changed, 30 insertions(+), 68 deletions(-)
diff --git a/arch/arm/common/Kconfig b/arch/arm/common/Kconfig
index c8e198631d41..286ea014c015 100644
--- a/arch/arm/common/Kconfig
+++ b/arch/arm/common/Kconfig
@@ -1,7 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
config SA1111
bool
- select DMABOUNCE if !ARCH_PXA
config DMABOUNCE
bool
diff --git a/arch/arm/common/sa1111.c b/arch/arm/common/sa1111.c
index 7df003b149c6..a00915883f78 100644
--- a/arch/arm/common/sa1111.c
+++ b/arch/arm/common/sa1111.c
@@ -1391,70 +1391,9 @@ void sa1111_driver_unregister(struct sa1111_driver *driver)
}
EXPORT_SYMBOL(sa1111_driver_unregister);
-#ifdef CONFIG_DMABOUNCE
-/*
- * 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.
- *
- * This routine only identifies whether or not a given DMA address
- * is susceptible to the bug.
- *
- * This should only get called for sa1111_device types due to the
- * way we configure our device dma_masks.
- */
-static int sa1111_needs_bounce(struct device *dev, dma_addr_t addr, size_t size)
-{
- /*
- * 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.
- */
- return (machine_is_assabet() || machine_is_pfs168()) &&
- (addr >= 0xc8000000 || (addr + size) >= 0xc8000000);
-}
-
-static int sa1111_notifier_call(struct notifier_block *n, unsigned long action,
- void *data)
-{
- struct sa1111_dev *dev = to_sa1111_device(data);
-
- switch (action) {
- case BUS_NOTIFY_ADD_DEVICE:
- if (dev->dev.dma_mask && dev->dma_mask < 0xffffffffUL) {
- int ret = dmabounce_register_dev(&dev->dev, 1024, 4096,
- sa1111_needs_bounce);
- if (ret)
- dev_err(&dev->dev, "failed to register with dmabounce: %d\n", ret);
- }
- break;
-
- case BUS_NOTIFY_DEL_DEVICE:
- if (dev->dev.dma_mask && dev->dma_mask < 0xffffffffUL)
- dmabounce_unregister_dev(&dev->dev);
- break;
- }
- return NOTIFY_OK;
-}
-
-static struct notifier_block sa1111_bus_notifier = {
- .notifier_call = sa1111_notifier_call,
-};
-#endif
-
static int __init sa1111_init(void)
{
int ret = bus_register(&sa1111_bus_type);
-#ifdef CONFIG_DMABOUNCE
- if (ret == 0)
- bus_register_notifier(&sa1111_bus_type, &sa1111_bus_notifier);
-#endif
if (ret == 0)
platform_driver_register(&sa1111_device_driver);
return ret;
@@ -1463,9 +1402,6 @@ static int __init sa1111_init(void)
static void __exit sa1111_exit(void)
{
platform_driver_unregister(&sa1111_device_driver);
-#ifdef CONFIG_DMABOUNCE
- bus_unregister_notifier(&sa1111_bus_type, &sa1111_bus_notifier);
-#endif
bus_unregister(&sa1111_bus_type);
}
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 3c7c64ff3c0a..5f2fa46c7958 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1260,7 +1260,8 @@ void usb_hcd_unlink_urb_from_ep(struct usb_hcd *hcd, struct urb *urb)
EXPORT_SYMBOL_GPL(usb_hcd_unlink_urb_from_ep);
/*
- * Some usb host controllers can only perform dma using a small SRAM area.
+ * Some usb host controllers can only perform dma using a small SRAM area,
+ * or that have restrictions in addressable DRAM.
* The usb core itself is however optimized for host controllers that can dma
* using regular system memory - like pci devices doing bus mastering.
*
@@ -3095,8 +3096,18 @@ int usb_hcd_setup_local_mem(struct usb_hcd *hcd, phys_addr_t phys_addr,
if (IS_ERR(hcd->localmem_pool))
return PTR_ERR(hcd->localmem_pool);
- local_mem = devm_memremap(hcd->self.sysdev, phys_addr,
- size, MEMREMAP_WC);
+ /*
+ * if a physical SRAM address was passed, map it, otherwise
+ * allocate system memory as a buffer.
+ */
+ if (phys_addr)
+ local_mem = devm_memremap(hcd->self.sysdev, phys_addr,
+ size, MEMREMAP_WC);
+ else
+ local_mem = dmam_alloc_attrs(hcd->self.sysdev, size, &dma,
+ GFP_KERNEL,
+ DMA_ATTR_WRITE_COMBINE);
+
if (IS_ERR(local_mem))
return PTR_ERR(local_mem);
diff --git a/drivers/usb/host/ohci-sa1111.c b/drivers/usb/host/ohci-sa1111.c
index 137f66f6977f..488033f2e144 100644
--- a/drivers/usb/host/ohci-sa1111.c
+++ b/drivers/usb/host/ohci-sa1111.c
@@ -206,6 +206,22 @@ static int ohci_hcd_sa1111_probe(struct sa1111_dev *dev)
goto err1;
}
+ /*
+ * 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.
+ */
+ if (machine_is_assabet()) {
+ ret = usb_hcd_setup_local_mem(hcd, 0, 0, SZ_64K);
+ if (ret)
+ goto out_err1;
+ }
+
if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len, hcd_name)) {
dev_dbg(&dev->dev, "request_mem_region failed\n");
ret = -EBUSY;
