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ARM: sa1111: register sa1111 devices with dmabounce in bus notifier
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Use the bus notifier to register sa1111 devices with dmabounce, rather
than after the device has been registered, potentially racing with
driver binding.

Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Russell King committed Mar 24, 2012
1 parent 2213536 commit 09a2ba2
Showing 1 changed file with 74 additions and 55 deletions.
129 changes: 74 additions & 55 deletions arch/arm/common/sa1111.c
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Original file line number Diff line number Diff line change
Expand Up @@ -603,36 +603,6 @@ sa1111_configure_smc(struct sa1111 *sachip, int sdram, unsigned int drac,
}
#endif

#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);
}
#endif

static void sa1111_dev_release(struct device *_dev)
{
struct sa1111_dev *dev = SA1111_DEV(_dev);
Expand Down Expand Up @@ -660,7 +630,6 @@ sa1111_init_one_child(struct sa1111 *sachip, struct resource *parent,
dev->dev.parent = sachip->dev;
dev->dev.bus = &sa1111_bus_type;
dev->dev.release = sa1111_dev_release;
dev->dev.coherent_dma_mask = sachip->dev->coherent_dma_mask;
dev->res.start = sachip->phys + info->offset;
dev->res.end = dev->res.start + 511;
dev->res.name = dev_name(&dev->dev);
Expand All @@ -671,6 +640,16 @@ sa1111_init_one_child(struct sa1111 *sachip, struct resource *parent,
for (i = 0; i < ARRAY_SIZE(info->irq); i++)
dev->irq[i] = sachip->irq_base + info->irq[i];

/*
* If the parent device has a DMA mask associated with it,
* propagate it down to the children.
*/
if (sachip->dev->dma_mask) {
dev->dma_mask = *sachip->dev->dma_mask;
dev->dev.dma_mask = &dev->dma_mask;
dev->dev.coherent_dma_mask = sachip->dev->coherent_dma_mask;
}

ret = request_resource(parent, &dev->res);
if (ret) {
printk("SA1111: failed to allocate resource for %s\n",
Expand All @@ -680,36 +659,12 @@ sa1111_init_one_child(struct sa1111 *sachip, struct resource *parent,
goto out;
}


ret = device_register(&dev->dev);
if (ret) {
release_resource(&dev->res);
kfree(dev);
goto out;
}

#ifdef CONFIG_DMABOUNCE
/*
* If the parent device has a DMA mask associated with it,
* propagate it down to the children.
*/
if (sachip->dev->dma_mask) {
dev->dma_mask = *sachip->dev->dma_mask;
dev->dev.dma_mask = &dev->dma_mask;

if (dev->dma_mask != 0xffffffffUL) {
ret = dmabounce_register_dev(&dev->dev, 1024, 4096,
sa1111_needs_bounce);
if (ret) {
dev_err(&dev->dev, "SA1111: Failed to register"
" with dmabounce\n");
device_unregister(&dev->dev);
}
}
}
#endif

out:
return ret;
}

Expand Down Expand Up @@ -1411,9 +1366,70 @@ 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 = SA1111_DEV(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;
Expand All @@ -1422,6 +1438,9 @@ 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);
}

Expand Down

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