On Wed, 2007-05-02 at 02:32 +0200, Oliver Endriss wrote:
> Jon Burgess wrote:
> > Sorry for the delay. I wanted to track down the DMA sync bug before I
> > came back to look at this again.
> >
> > I have added saa7146_vmalloc_destroy_pgtable() which frees the resources
>
> Shouldn't it better be called saa7146_vfree_destroy_pgtable()?
> ^^^^^
Sounds good. Implemented in the attached patch.
> > allocated by saa7146_vmalloc_build_pgtable() and updated the callers in
> > budget-core.c and av711o.c. I have also been through the updated
> > functions and updated the error paths to ensure they free all allocated
> > resources on error.
> >
> > Also included in this patch are the previous fixes for pci_unmap_sg()
> > and syncing the PCI streamed data to work with a SWIOTLB and match the
> > requirements documented in DMA-API.txt.
>
> Thanks, looks perfect.
>
> @all:
> Any comments?
>
> Btw, why did DMA work without pci_dma_sync_sg_for_cpu()
> on most machines?
It is probably the CPU cache snooping which happens on x86 to ensure
cache coherency. Most non-x86 architectures require manual cache
writeback and invalidation. Having cache coherency costs transistors,
power, design complexity etc. so RISC architectures avoid it at the
expense of a slightly more complex driver.
The 2003 OLS presentation "Integrating DMA Into the Generic Device
Model" has some more details and background.
http://licensing.steeleye.com/support/papers/ols_2003_dma.pdf
Jon
Signed-off-by: Jon Burgess <jburgess777@xxxxxxxxxxxxxx>
diff -r e3779e21a314 linux/drivers/media/common/saa7146_core.c
--- a/linux/drivers/media/common/saa7146_core.c Tue May 01 10:48:09 2007 -0300
+++ b/linux/drivers/media/common/saa7146_core.c Tue May 01 21:54:19 2007 +0100
@@ -136,28 +136,45 @@ char *saa7146_vmalloc_build_pgtable(stru
char *mem = vmalloc_32(length);
int slen = 0;
- if (NULL == mem) {
- return NULL;
- }
-
- if (!(pt->slist = vmalloc_to_sg(mem, pages))) {
- vfree(mem);
- return NULL;
- }
-
- if (saa7146_pgtable_alloc(pci, pt)) {
- kfree(pt->slist);
- pt->slist = NULL;
- vfree(mem);
- return NULL;
- }
-
- slen = pci_map_sg(pci,pt->slist,pages,PCI_DMA_FROMDEVICE);
- if (0 != saa7146_pgtable_build_single(pci, pt, pt->slist, slen)) {
- return NULL;
- }
+ if (NULL == mem)
+ goto err_null;
+
+ if (!(pt->slist = vmalloc_to_sg(mem, pages)))
+ goto err_free_mem;
+
+ if (saa7146_pgtable_alloc(pci, pt))
+ goto err_free_slist;
+
+ pt->nents = pages;
+ slen = pci_map_sg(pci,pt->slist,pt->nents,PCI_DMA_FROMDEVICE);
+ if (0 == slen)
+ goto err_free_pgtable;
+
+ if (0 != saa7146_pgtable_build_single(pci, pt, pt->slist, slen))
+ goto err_unmap_sg;
return mem;
+
+err_unmap_sg:
+ pci_unmap_sg(pci, pt->slist, pt->nents, PCI_DMA_FROMDEVICE);
+err_free_pgtable:
+ saa7146_pgtable_free(pci, pt);
+err_free_slist:
+ kfree(pt->slist);
+ pt->slist = NULL;
+err_free_mem:
+ vfree(mem);
+err_null:
+ return NULL;
+}
+
+void saa7146_vfree_destroy_pgtable(struct pci_dev *pci, char *mem, struct saa7146_pgtable *pt)
+{
+ pci_unmap_sg(pci, pt->slist, pt->nents, PCI_DMA_FROMDEVICE);
+ saa7146_pgtable_free(pci, pt);
+ kfree(pt->slist);
+ pt->slist = NULL;
+ vfree(mem);
}
void saa7146_pgtable_free(struct pci_dev *pci, struct saa7146_pgtable *pt)
@@ -166,8 +183,6 @@ void saa7146_pgtable_free(struct pci_dev
return;
pci_free_consistent(pci, pt->size, pt->cpu, pt->dma);
pt->cpu = NULL;
- kfree(pt->slist);
- pt->slist = NULL;
}
int saa7146_pgtable_alloc(struct pci_dev *pci, struct saa7146_pgtable *pt)
@@ -532,6 +547,7 @@ EXPORT_SYMBOL_GPL(saa7146_pgtable_free);
EXPORT_SYMBOL_GPL(saa7146_pgtable_free);
EXPORT_SYMBOL_GPL(saa7146_pgtable_build_single);
EXPORT_SYMBOL_GPL(saa7146_vmalloc_build_pgtable);
+EXPORT_SYMBOL_GPL(saa7146_vfree_destroy_pgtable);
EXPORT_SYMBOL_GPL(saa7146_wait_for_debi_done);
EXPORT_SYMBOL_GPL(saa7146_setgpio);
diff -r e3779e21a314 linux/drivers/media/dvb/ttpci/av7110.c
--- a/linux/drivers/media/dvb/ttpci/av7110.c Tue May 01 10:48:09 2007 -0300
+++ b/linux/drivers/media/dvb/ttpci/av7110.c Tue May 01 22:29:11 2007 +0100
@@ -1245,6 +1245,9 @@ static void vpeirq(unsigned long data)
if (!budget->feeding1 || (newdma == olddma))
return;
+
+ /* Ensure streamed PCI data is synced to CPU */
+ pci_dma_sync_sg_for_cpu(budget->dev->pci, budget->pt.slist, budget->pt.nents, PCI_DMA_FROMDEVICE);
#if 0 /* keep */
/* track rps1 activity */
@@ -2679,8 +2682,8 @@ err_pci_free_5:
err_pci_free_5:
pci_free_consistent(pdev, 8192, av7110->debi_virt, av7110->debi_bus);
err_saa71466_vfree_4:
- if (!av7110->grabbing)
- saa7146_pgtable_free(pdev, &av7110->pt);
+ if (av7110->grabbing)
+ saa7146_vfree_destroy_pgtable(pdev, av7110->grabbing, &av7110->pt);
err_i2c_del_3:
i2c_del_adapter(&av7110->i2c_adap);
err_dvb_unregister_adapter_2:
@@ -2710,7 +2713,7 @@ static int __devexit av7110_detach(struc
SAA7146_ISR_CLEAR(saa, MASK_10);
msleep(50);
tasklet_kill(&av7110->vpe_tasklet);
- saa7146_pgtable_free(saa->pci, &av7110->pt);
+ saa7146_vfree_destroy_pgtable(saa->pci, av7110->grabbing, &av7110->pt);
}
av7110_exit_v4l(av7110);
diff -r e3779e21a314 linux/drivers/media/dvb/ttpci/budget-core.c
--- a/linux/drivers/media/dvb/ttpci/budget-core.c Tue May 01 10:48:09 2007 -0300
+++ b/linux/drivers/media/dvb/ttpci/budget-core.c Tue May 01 22:28:31 2007 +0100
@@ -195,6 +195,9 @@ static void vpeirq(unsigned long data)
u32 newdma = saa7146_read(budget->dev, PCI_VDP3);
u32 count;
+ /* Ensure streamed PCI data is synced to CPU */
+ pci_dma_sync_sg_for_cpu(budget->dev->pci, budget->pt.slist, budget->pt.nents, PCI_DMA_FROMDEVICE);
+
/* nearest lower position divisible by 188 */
newdma -= newdma % 188;
@@ -504,16 +507,16 @@ int ttpci_budget_init(struct budget *bud
strcpy(budget->i2c_adap.name, budget->card->name);
if (i2c_add_adapter(&budget->i2c_adap) < 0) {
- dvb_unregister_adapter(&budget->dvb_adapter);
- return -ENOMEM;
+ ret = -ENOMEM;
+ goto err_dvb_unregister;
}
ttpci_eeprom_parse_mac(&budget->i2c_adap, budget->dvb_adapter.proposed_mac);
- if (NULL ==
- (budget->grabbing = saa7146_vmalloc_build_pgtable(dev->pci, budget->buffer_size, &budget->pt))) {
+ budget->grabbing = saa7146_vmalloc_build_pgtable(dev->pci, budget->buffer_size, &budget->pt);
+ if (NULL == budget->grabbing) {
ret = -ENOMEM;
- goto err;
+ goto err_del_i2c;
}
saa7146_write(dev, PCI_BT_V1, 0x001c0000);
@@ -526,14 +529,16 @@ int ttpci_budget_init(struct budget *bud
if (bi->type != BUDGET_FS_ACTIVY)
saa7146_setgpio(dev, 2, SAA7146_GPIO_OUTHI);
- if (budget_register(budget) == 0) {
- return 0;
- }
-err:
+ if (budget_register(budget) == 0)
+ return 0; /* Everything OK */
+
+ /* An error occurred, cleanup resources */
+ saa7146_vfree_destroy_pgtable(dev->pci, budget->grabbing, &budget->pt);
+
+err_del_i2c:
i2c_del_adapter(&budget->i2c_adap);
- vfree(budget->grabbing);
-
+err_dvb_unregister:
dvb_unregister_adapter(&budget->dvb_adapter);
return ret;
@@ -555,15 +560,13 @@ int ttpci_budget_deinit(struct budget *b
budget_unregister(budget);
+ tasklet_kill(&budget->vpe_tasklet);
+
+ saa7146_vfree_destroy_pgtable(dev->pci, budget->grabbing, &budget->pt);
+
i2c_del_adapter(&budget->i2c_adap);
dvb_unregister_adapter(&budget->dvb_adapter);
-
- tasklet_kill(&budget->vpe_tasklet);
-
- saa7146_pgtable_free(dev->pci, &budget->pt);
-
- vfree(budget->grabbing);
return 0;
}
diff -r e3779e21a314 linux/include/media/saa7146.h
--- a/linux/include/media/saa7146.h Tue May 01 10:48:09 2007 -0300
+++ b/linux/include/media/saa7146.h Tue May 01 22:20:38 2007 +0100
@@ -70,6 +70,7 @@ struct saa7146_pgtable {
unsigned long offset;
/* used for custom pagetables (used for example by budget dvb cards) */
struct scatterlist *slist;
+ int nents;
};
struct saa7146_pci_extension_data {
@@ -181,6 +182,7 @@ void saa7146_pgtable_free(struct pci_dev
void saa7146_pgtable_free(struct pci_dev *pci, struct saa7146_pgtable *pt);
int saa7146_pgtable_build_single(struct pci_dev *pci, struct saa7146_pgtable *pt, struct scatterlist *list, int length );
char *saa7146_vmalloc_build_pgtable(struct pci_dev *pci, long length, struct saa7146_pgtable *pt);
+void saa7146_vfree_destroy_pgtable(struct pci_dev *pci, char *mem, struct saa7146_pgtable *pt);
void saa7146_setgpio(struct saa7146_dev *dev, int port, u32 data);
int saa7146_wait_for_debi_done(struct saa7146_dev *dev, int nobusyloop);
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