[PATCH 16/20] ARM: sa1111: register sa1111 devices with dmabounce in bus notifier
Russell King - ARM Linux
linux at arm.linux.org.uk
Fri Feb 3 14:59:57 EST 2012
Use the bus notifier to register sa1111 devices with dmabounce, rather
than after the device has been registered, potentially racing with
driver binding.
Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
---
arch/arm/common/sa1111.c | 129 ++++++++++++++++++++++++++-------------------
1 files changed, 74 insertions(+), 55 deletions(-)
diff --git a/arch/arm/common/sa1111.c b/arch/arm/common/sa1111.c
index 17694cf..7b4351b 100644
--- a/arch/arm/common/sa1111.c
+++ b/arch/arm/common/sa1111.c
@@ -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);
@@ -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);
@@ -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",
@@ -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;
}
@@ -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;
@@ -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);
}
--
1.7.4.4
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