Patchwork [1/3] TILER: Move dma_alloc_coherent call to tiler init

login
register
mail settings
Submitter Bryan Wu
Date July 13, 2010, 3:22 a.m.
Message ID <1278991369-17962-2-git-send-email-bryan.wu@canonical.com>
Download mbox | patch
Permalink /patch/58699/
State Accepted
Delegated to: Tim Gardner
Headers show

Comments

Bryan Wu - July 13, 2010, 3:22 a.m.
From: David Sin <davidsin@ti.com>

Instead of allocating and freeing PAT page array
memory each time, allocate 128k upfront and reuse the
memory.  This will avoid the possibilty of not being
able to obtain the memory after driver initialization.

Signed-off-by: David Sin <davidsin@ti.com>
---
 drivers/media/video/tiler/tiler.c |   27 +++++++++++++++------------
 1 files changed, 15 insertions(+), 12 deletions(-)
Bryan Wu - July 13, 2010, 3:34 a.m.
On 07/13/2010 11:22 AM, Bryan Wu wrote:
> From: David Sin <davidsin@ti.com>
> 
> Instead of allocating and freeing PAT page array
> memory each time, allocate 128k upfront and reuse the
> memory.  This will avoid the possibilty of not being
> able to obtain the memory after driver initialization.
> 
> Signed-off-by: David Sin <davidsin@ti.com>
> ---
>  drivers/media/video/tiler/tiler.c |   27 +++++++++++++++------------
>  1 files changed, 15 insertions(+), 12 deletions(-)
> 

[snip]

>  
> +	/* Array of physical pages for PAT programming, which must be a 16-byte
> +	   aligned physical address
> +	*/
> +	dmac_va = dma_alloc_coherent(NULL, TILER_WIDTH * TILER_HEIGHT *
> +					sizeof(*dmac_va), &dmac_pa, GFP_ATOMIC);
> +	if (!dmac_va)
> +		return -ENOMEM;
> +

Returning -ENOMEM is not enough here. IMHO, at least it should deinit
sita_init(). Or just follow the error exit path.

Thanks,
-Bryan
Tim Gardner - July 15, 2010, 2 p.m.
On 07/12/2010 09:34 PM, Bryan Wu wrote:
> On 07/13/2010 11:22 AM, Bryan Wu wrote:
>> From: David Sin<davidsin@ti.com>
>>
>> Instead of allocating and freeing PAT page array
>> memory each time, allocate 128k upfront and reuse the
>> memory.  This will avoid the possibilty of not being
>> able to obtain the memory after driver initialization.
>>
>> Signed-off-by: David Sin<davidsin@ti.com>
>> ---
>>   drivers/media/video/tiler/tiler.c |   27 +++++++++++++++------------
>>   1 files changed, 15 insertions(+), 12 deletions(-)
>>
>
> [snip]
>
>>
>> +	/* Array of physical pages for PAT programming, which must be a 16-byte
>> +	   aligned physical address
>> +	*/
>> +	dmac_va = dma_alloc_coherent(NULL, TILER_WIDTH * TILER_HEIGHT *
>> +					sizeof(*dmac_va),&dmac_pa, GFP_ATOMIC);
>> +	if (!dmac_va)
>> +		return -ENOMEM;
>> +
>
> Returning -ENOMEM is not enough here. IMHO, at least it should deinit
> sita_init(). Or just follow the error exit path.
>
> Thanks,
> -Bryan
>

Eh? I think this looks OK. If you can't allocate DMA memory, then you're 
pretty much screwed and can do nothing else but exit.

applied

Patch

diff --git a/drivers/media/video/tiler/tiler.c b/drivers/media/video/tiler/tiler.c
index c8008b0..bd35248 100644
--- a/drivers/media/video/tiler/tiler.c
+++ b/drivers/media/video/tiler/tiler.c
@@ -120,6 +120,8 @@  static u32 id;
 static struct mutex mtx;
 static struct tcm *tcm[TILER_FORMATS];
 static struct tmm *tmm[TILER_FORMATS];
+static u32 *dmac_va;
+static dma_addr_t dmac_pa;
 
 #define TCM(fmt)        tcm[(fmt) - TILFMT_8BIT]
 #define TCM_SS(ssptr)   TCM(TILER_GET_ACC_MODE(ssptr))
@@ -829,34 +831,24 @@  static s32 tiler_mmap(struct file *filp, struct vm_area_struct *vma)
 static s32 refill_pat(struct tmm *tmm, struct tcm_area *area, u32 *ptr)
 {
 	s32 res = 0;
-	s32 size = tcm_sizeof(*area) * sizeof(*ptr);
-	u32 *page;
-	dma_addr_t page_pa;
 	struct pat_area p_area = {0};
 	struct tcm_area slice, area_s;
 
-	/* must be a 16-byte aligned physical address */
-	page = dma_alloc_coherent(NULL, size, &page_pa, GFP_ATOMIC);
-	if (!page)
-		return -ENOMEM;
-
 	tcm_for_each_slice(slice, *area, area_s) {
 		p_area.x0 = slice.p0.x;
 		p_area.y0 = slice.p0.y;
 		p_area.x1 = slice.p1.x;
 		p_area.y1 = slice.p1.y;
 
-		memcpy(page, ptr, sizeof(*ptr) * tcm_sizeof(slice));
+		memcpy(dmac_va, ptr, sizeof(*ptr) * tcm_sizeof(slice));
 		ptr += tcm_sizeof(slice);
 
-		if (tmm_map(tmm, p_area, page_pa)) {
+		if (tmm_map(tmm, p_area, dmac_pa)) {
 			res = -EFAULT;
 			break;
 		}
 	}
 
-	dma_free_coherent(NULL, size, page, page_pa);
-
 	return res;
 }
 
@@ -1423,6 +1415,9 @@  static void __exit tiler_exit(void)
 
 	mutex_unlock(&mtx);
 
+	dma_free_coherent(NULL, TILER_WIDTH * TILER_HEIGHT * sizeof(*dmac_va),
+							dmac_va, dmac_pa);
+
 	/* close containers only once */
 	for (i = TILFMT_8BIT; i <= TILFMT_MAX; i++) {
 		/* remove identical containers (tmm is unique per tcm) */
@@ -1502,6 +1497,14 @@  static s32 __init tiler_init(void)
 	TMM_SET(TILFMT_32BIT, tmm_pat);
 	TMM_SET(TILFMT_PAGE, tmm_pat);
 
+	/* Array of physical pages for PAT programming, which must be a 16-byte
+	   aligned physical address
+	*/
+	dmac_va = dma_alloc_coherent(NULL, TILER_WIDTH * TILER_HEIGHT *
+					sizeof(*dmac_va), &dmac_pa, GFP_ATOMIC);
+	if (!dmac_va)
+		return -ENOMEM;
+
 	tiler_device = kmalloc(sizeof(*tiler_device), GFP_KERNEL);
 	if (!tiler_device || !sita || !tmm_pat) {
 		r = -ENOMEM;