Some platforms don't have DMA, but we should still be able to build
USB drivers for these platforms. They could still be used through
vhci_hcd, usbip_host, or maybe something like USB passthrough in UML
from a capable host.
This is admittedly ugly with all the #ifdefs, but it is necessary to
get around linker errors like these:
drivers/built-in.o: In function `dma_unmap_sg_attrs':
include/linux/dma-mapping.h:183: undefined reference to `bad_dma_ops'
drivers/built-in.o: In function `dma_unmap_single_attrs':
include/linux/dma-mapping.h:148: undefined reference to `bad_dma_ops'
drivers/built-in.o: In function `dma_map_sg_attrs':
include/linux/dma-mapping.h:168: undefined reference to `bad_dma_ops'
drivers/built-in.o: In function `dma_map_page':
include/linux/dma-mapping.h:196: undefined reference to `bad_dma_ops'
drivers/built-in.o: In function `dma_mapping_error':
include/linux/dma-mapping.h:430: undefined reference to `bad_dma_ops'
drivers/built-in.o:include/linux/dma-mapping.h:131: more undefined references to `bad_dma_ops' follow
If any of the new warnings trigger, the correct solution is almost
certainly to add a CONFIG_HAS_DMA dependency in the Kconfig menu for
the responsible driver.
Signed-off-by: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
---
drivers/usb/core/buffer.c | 17 +++++++++++++++++
drivers/usb/core/hcd.c | 45 +++++++++++++++++++++++++++++++++++++++------
include/linux/usb/hcd.h | 8 ++++++++
3 files changed, 64 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/core/buffer.c b/drivers/usb/core/buffer.c
index 89f2e77..427b131 100644
--- a/drivers/usb/core/buffer.c
+++ b/drivers/usb/core/buffer.c
@@ -59,13 +59,16 @@ void __init usb_init_pool_max(void)
*/
int hcd_buffer_create(struct usb_hcd *hcd)
{
+#ifdef CONFIG_HAS_DMA
char name[16];
int i, size;
+#endif
if (!hcd->self.controller->dma_mask &&
!(hcd->driver->flags & HCD_LOCAL_MEM))
return 0;
+#ifdef CONFIG_HAS_DMA
for (i = 0; i < HCD_BUFFER_POOLS; i++) {
size = pool_max[i];
if (!size)
@@ -78,6 +81,7 @@ int hcd_buffer_create(struct usb_hcd *hcd)
return -ENOMEM;
}
}
+#endif
return 0;
}
@@ -91,6 +95,7 @@ int hcd_buffer_create(struct usb_hcd *hcd)
*/
void hcd_buffer_destroy(struct usb_hcd *hcd)
{
+#ifdef CONFIG_HAS_DMA
int i;
for (i = 0; i < HCD_BUFFER_POOLS; i++) {
@@ -101,6 +106,7 @@ void hcd_buffer_destroy(struct usb_hcd *hcd)
hcd->pool[i] = NULL;
}
}
+#endif
}
@@ -116,7 +122,9 @@ void *hcd_buffer_alloc(
)
{
struct usb_hcd *hcd = bus_to_hcd(bus);
+#ifdef CONFIG_HAS_DMA
int i;
+#endif
/* some USB hosts just use PIO */
if (!bus->controller->dma_mask &&
@@ -125,11 +133,16 @@ void *hcd_buffer_alloc(
return kmalloc(size, mem_flags);
}
+#ifdef CONFIG_HAS_DMA
for (i = 0; i < HCD_BUFFER_POOLS; i++) {
if (size <= pool_max[i])
return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
}
return dma_alloc_coherent(hcd->self.controller, size, dma, mem_flags);
+#else
+ WARN_ON_NO_DMA();
+ return NULL;
+#endif
}
void hcd_buffer_free(
@@ -140,7 +153,9 @@ void hcd_buffer_free(
)
{
struct usb_hcd *hcd = bus_to_hcd(bus);
+#ifdef CONFIG_HAS_DMA
int i;
+#endif
if (!addr)
return;
@@ -151,6 +166,7 @@ void hcd_buffer_free(
return;
}
+#ifdef CONFIG_HAS_DMA
for (i = 0; i < HCD_BUFFER_POOLS; i++) {
if (size <= pool_max[i]) {
dma_pool_free(hcd->pool[i], addr, dma);
@@ -158,4 +174,5 @@ void hcd_buffer_free(
}
}
dma_free_coherent(hcd->self.controller, size, addr, dma);
+#endif
}
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index df0e3b9..1eb214d 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1408,12 +1408,15 @@ static void hcd_free_coherent(struct usb_bus *bus, dma_addr_t *dma_handle,
void usb_hcd_unmap_urb_setup_for_dma(struct usb_hcd *hcd, struct urb *urb)
{
- if (urb->transfer_flags & URB_SETUP_MAP_SINGLE)
+ if (urb->transfer_flags & URB_SETUP_MAP_SINGLE) {
+#ifdef CONFIG_HAS_DMA
dma_unmap_single(hcd->self.controller,
urb->setup_dma,
sizeof(struct usb_ctrlrequest),
DMA_TO_DEVICE);
- else if (urb->transfer_flags & URB_SETUP_MAP_LOCAL)
+#endif
+ WARN_ON_NO_DMA();
+ } else if (urb->transfer_flags & URB_SETUP_MAP_LOCAL)
hcd_free_coherent(urb->dev->bus,
&urb->setup_dma,
(void **) &urb->setup_packet,
@@ -1440,27 +1443,37 @@ void usb_hcd_unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
usb_hcd_unmap_urb_setup_for_dma(hcd, urb);
dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
- if (urb->transfer_flags & URB_DMA_MAP_SG)
+ if (urb->transfer_flags & URB_DMA_MAP_SG) {
+#ifdef CONFIG_HAS_DMA
dma_unmap_sg(hcd->self.controller,
urb->sg,
urb->num_sgs,
dir);
- else if (urb->transfer_flags & URB_DMA_MAP_PAGE)
+#endif
+ WARN_ON_NO_DMA();
+ } else if (urb->transfer_flags & URB_DMA_MAP_PAGE) {
+#ifdef CONFIG_HAS_DMA
dma_unmap_page(hcd->self.controller,
urb->transfer_dma,
urb->transfer_buffer_length,
dir);
- else if (urb->transfer_flags & URB_DMA_MAP_SINGLE)
+#endif
+ WARN_ON_NO_DMA();
+ } else if (urb->transfer_flags & URB_DMA_MAP_SINGLE) {
+#ifdef CONFIG_HAS_DMA
dma_unmap_single(hcd->self.controller,
urb->transfer_dma,
urb->transfer_buffer_length,
dir);
- else if (urb->transfer_flags & URB_MAP_LOCAL)
+#endif
+ WARN_ON_NO_DMA();
+ } else if (urb->transfer_flags & URB_MAP_LOCAL) {
hcd_free_coherent(urb->dev->bus,
&urb->transfer_dma,
&urb->transfer_buffer,
urb->transfer_buffer_length,
dir);
+ }
/* Make it safe to call this routine more than once */
urb->transfer_flags &= ~(URB_DMA_MAP_SG | URB_DMA_MAP_PAGE |
@@ -1493,6 +1506,7 @@ int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
if (hcd->self.uses_pio_for_control)
return ret;
if (hcd->self.uses_dma) {
+#ifdef CONFIG_HAS_DMA
urb->setup_dma = dma_map_single(
hcd->self.controller,
urb->setup_packet,
@@ -1502,6 +1516,10 @@ int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
urb->setup_dma))
return -EAGAIN;
urb->transfer_flags |= URB_SETUP_MAP_SINGLE;
+#else
+ WARN_ON_NO_DMA();
+ return -EINVAL;
+#endif
} else if (hcd->driver->flags & HCD_LOCAL_MEM) {
ret = hcd_alloc_coherent(
urb->dev->bus, mem_flags,
@@ -1520,6 +1538,7 @@ int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
&& !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) {
if (hcd->self.uses_dma) {
if (urb->num_sgs) {
+#ifdef CONFIG_HAS_DMA
int n;
/* We don't support sg for isoc transfers ! */
@@ -1541,7 +1560,12 @@ int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
if (n != urb->num_sgs)
urb->transfer_flags |=
URB_DMA_SG_COMBINED;
+#else
+ WARN_ON_NO_DMA();
+ ret = -EINVAL;
+#endif
} else if (urb->sg) {
+#ifdef CONFIG_HAS_DMA
struct scatterlist *sg = urb->sg;
urb->transfer_dma = dma_map_page(
hcd->self.controller,
@@ -1554,10 +1578,15 @@ int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
ret = -EAGAIN;
else
urb->transfer_flags |= URB_DMA_MAP_PAGE;
+#else
+ WARN_ON_NO_DMA();
+ ret = -EINVAL;
+#endif
} else if (is_vmalloc_addr(urb->transfer_buffer)) {
WARN_ONCE(1, "transfer buffer not dma capable\n");
ret = -EAGAIN;
} else {
+#ifdef CONFIG_HAS_DMA
urb->transfer_dma = dma_map_single(
hcd->self.controller,
urb->transfer_buffer,
@@ -1568,6 +1597,10 @@ int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
ret = -EAGAIN;
else
urb->transfer_flags |= URB_DMA_MAP_SINGLE;
+#else
+ WARN_ON_NO_DMA();
+ ret = -EINVAL;
+#endif
}
} else if (hcd->driver->flags & HCD_LOCAL_MEM) {
ret = hcd_alloc_coherent(
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 4dcf844..51b816a 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -409,6 +409,14 @@ static inline bool hcd_periodic_completion_in_progress(struct usb_hcd *hcd,
return hcd->high_prio_bh.completing_ep == ep;
}
+#ifdef CONFIG_HAS_DMA
+#define WARN_ON_NO_DMA() do { } while (0)
+#else
+/* If this ever triggers, the correct fix is almost certainly
+ * to add a CONFIG_HAS_DMA dependency in the Kconfig for that driver. */
+#define WARN_ON_NO_DMA() WARN_ONCE(1, "HCD driver tried to use DMA memory")
+#endif
+
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,
int status);
--
1.9.1
--
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