diff mbox

[RFC,05/11] dma: amba-pl08x: Add support for different maximum transfer size

Message ID 1371416058-22047-6-git-send-email-tomasz.figa@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Tomasz Figa June 16, 2013, 8:54 p.m. UTC 
PL080S has separate register to store transfer size in, allowing single
transfer to be much larger than in standard PL080.

This patch makes the amba-pl08x driver aware of this and removes writing
transfer size to reserved bits of CH_CONTROL register on PL080S, which
was not a problem witn transfer sizes fitting the original bitfield
of PL080, but now would overwrite other fields.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
---
 drivers/dma/amba-pl08x.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

Comments

Linus Walleij June 17, 2013, 1:42 p.m. UTC | #1 
On Sun, Jun 16, 2013 at 10:54 PM, Tomasz Figa <tomasz.figa@gmail.com> wrote:

> PL080S has separate register to store transfer size in, allowing single
> transfer to be much larger than in standard PL080.
>
> This patch makes the amba-pl08x driver aware of this and removes writing
> transfer size to reserved bits of CH_CONTROL register on PL080S, which
> was not a problem witn transfer sizes fitting the original bitfield
> of PL080, but now would overwrite other fields.
>
> Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>

Very straight-forward.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij
Tomasz Figa June 17, 2013, 6:27 p.m. UTC | #2 
On Monday 17 of June 2013 15:42:15 Linus Walleij wrote:
> On Sun, Jun 16, 2013 at 10:54 PM, Tomasz Figa <tomasz.figa@gmail.com> 
wrote:
> > PL080S has separate register to store transfer size in, allowing
> > single
> > transfer to be much larger than in standard PL080.
> > 
> > This patch makes the amba-pl08x driver aware of this and removes
> > writing transfer size to reserved bits of CH_CONTROL register on
> > PL080S, which was not a problem witn transfer sizes fitting the
> > original bitfield of PL080, but now would overwrite other fields.
> > 
> > Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
> 
> Very straight-forward.
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Thanks.

Actually today I found another way of doing this, which wouldn't require 
checking PL08X_IS_PL080S flag at all.

Simply masking the transfer size in pl08x_cctl_bits() with mask of the 
original bitfield would be enough I think, as writes to those bits seem to 
be ignored on PL080S.

Best regards,
Tomasz
diff mbox

Patch

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index d1f1333..eb10eb8 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -112,6 +112,7 @@  struct vendor_data {
 	u8 config_offset;
 	u8 channels;
 	u32 flags;
+	u32 max_transfer_size;
 };
 
 /*
@@ -843,7 +844,10 @@  static inline void prep_byte_width_lli(struct pl08x_driver_data *pl08x,
 		struct pl08x_lli_build_data *bd,
 		u32 *cctl, u32 len, int num_llis, size_t *total_bytes)
 {
-	*cctl = pl08x_cctl_bits(*cctl, 1, 1, len);
+	if (pl08x->vd->flags & PL08X_IS_PL080S)
+		*cctl = pl08x_cctl_bits(*cctl, 1, 1, 0);
+	else
+		*cctl = pl08x_cctl_bits(*cctl, 1, 1, len);
 	pl08x_fill_lli_for_desc(bd, num_llis, len, *cctl, len);
 	(*total_bytes) += len;
 }
@@ -992,7 +996,7 @@  static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
 			 * MIN(buswidths)
 			 */
 			max_bytes_per_lli = bd.srcbus.buswidth *
-				PL080_CONTROL_TRANSFER_SIZE_MASK;
+						pl08x->vd->max_transfer_size;
 			dev_vdbg(&pl08x->adev->dev,
 				"%s max bytes per lli = %zu\n",
 				__func__, max_bytes_per_lli);
@@ -1025,8 +1029,14 @@  static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
 					"size 0x%08zx (remainder 0x%08zx)\n",
 					__func__, lli_len, bd.remainder);
 
-				cctl = pl08x_cctl_bits(cctl, bd.srcbus.buswidth,
-					bd.dstbus.buswidth, tsize);
+				if (pl08x->vd->flags & PL08X_IS_PL080S)
+					cctl = pl08x_cctl_bits(cctl,
+						bd.srcbus.buswidth,
+						bd.dstbus.buswidth, 0);
+				else
+					cctl = pl08x_cctl_bits(cctl,
+						bd.srcbus.buswidth,
+						bd.dstbus.buswidth, tsize);
 				pl08x_fill_lli_for_desc(&bd, num_llis++,
 						lli_len, cctl, tsize);
 				total_bytes += lli_len;
@@ -2092,24 +2102,28 @@  static struct vendor_data vendor_pl080 = {
 	.channels = 8,
 	.flags = PL08X_IS_DUALMASTER,
 	.config_offset = PL080_CH_CONFIG,
+	.max_transfer_size = PL080_CONTROL_TRANSFER_SIZE_MASK,
 };
 
 static struct vendor_data vendor_nomadik = {
 	.channels = 8,
 	.flags = PL08X_IS_DUALMASTER | PL08X_IS_NOMADIK,
 	.config_offset = PL080_CH_CONFIG,
+	.max_transfer_size = PL080_CONTROL_TRANSFER_SIZE_MASK,
 };
 
 static struct vendor_data vendor_pl080s = {
 	.channels = 8,
 	.flags = PL08X_IS_DUALMASTER | PL08X_IS_PL080S,
 	.config_offset = PL080S_CH_CONFIG,
+	.max_transfer_size = PL080S_CONTROL_TRANSFER_SIZE_MASK,
 };
 
 static struct vendor_data vendor_pl081 = {
 	.channels = 2,
 	.flags = 0,
 	.config_offset = PL080_CH_CONFIG,
+	.max_transfer_size = PL080_CONTROL_TRANSFER_SIZE_MASK,
 };
 
 static struct amba_id pl08x_ids[] = {