Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-14 Thread Vignesh R
On 3/6/2017 5:17 PM, Vignesh R wrote: > > > On Thursday 02 March 2017 07:59 PM, Boris Brezillon wrote: >> On Thu, 2 Mar 2017 19:24:43 +0530 >> Vignesh R wrote: [...] >>> >>> If its at SPI level, then I guess each individual drivers which cannot >>> handle vmalloc'd buffers will have to impleme

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-06 Thread Vignesh R
On Thursday 02 March 2017 07:59 PM, Boris Brezillon wrote: > On Thu, 2 Mar 2017 19:24:43 +0530 > Vignesh R wrote: > >> > Not really, I am debugging another issue with UBIFS on DRA74 EVM (ARM > cortex-a15) wherein pages allocated by vmalloc are in highmem region > that are n

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-03 Thread Vignesh R
>>> Not really, I am debugging another issue with UBIFS on DRA74 EVM (ARM >>> cortex-a15) wherein pages allocated by vmalloc are in highmem region >>> that are not addressable using 32 bit addresses and is backed by LPAE. >>> So, a 32 bit DMA cannot access these buffers at all. >>> When dm

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-03 Thread Mark Brown
On Thu, Mar 02, 2017 at 08:49:00PM +0100, Boris Brezillon wrote: > 1/ for big transfers, dynamically allocating a bounce buffer on demand >(and freeing it after the DMA operation) might fail, or might induce >some latency, especially when the system is under high mem pressure. >Allocat

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-03 Thread Frode Isaksen
On 02/03/2017 16:25, Boris Brezillon wrote: > On Thu, 2 Mar 2017 16:03:17 +0100 > Frode Isaksen wrote: > >> On 02/03/2017 15:29, Boris Brezillon wrote: >>> On Thu, 2 Mar 2017 19:24:43 +0530 >>> Vignesh R wrote: >>> >>> Not really, I am debugging another issue with UBIFS on

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-02 Thread Boris Brezillon
On Thu, 2 Mar 2017 17:00:41 + Mark Brown wrote: > On Thu, Mar 02, 2017 at 03:29:21PM +0100, Boris Brezillon wrote: > > Vignesh R wrote: > > > > Or SPI core can be extended in a way similar to this RFC. That is, SPI > > > master driver will set a flag to request SPI core to use of bounce >

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-02 Thread Mark Brown
On Thu, Mar 02, 2017 at 03:29:21PM +0100, Boris Brezillon wrote: > Vignesh R wrote: > > Or SPI core can be extended in a way similar to this RFC. That is, SPI > > master driver will set a flag to request SPI core to use of bounce > > buffer for vmalloc'd buffers. And spi_map_buf() just uses bounc

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-02 Thread Cyrille Pitchen
Le 02/03/2017 à 15:29, Boris Brezillon a écrit : > On Thu, 2 Mar 2017 19:24:43 +0530 > Vignesh R wrote: > >> > Not really, I am debugging another issue with UBIFS on DRA74 EVM (ARM > cortex-a15) wherein pages allocated by vmalloc are in highmem region > that are not addressab

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-02 Thread Boris Brezillon
On Thu, 2 Mar 2017 16:03:17 +0100 Frode Isaksen wrote: > On 02/03/2017 15:29, Boris Brezillon wrote: > > On Thu, 2 Mar 2017 19:24:43 +0530 > > Vignesh R wrote: > > > >> > > Not really, I am debugging another issue with UBIFS on DRA74 EVM (ARM > > cortex-a15) wherein pages al

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-02 Thread Frode Isaksen
On 02/03/2017 15:29, Boris Brezillon wrote: > On Thu, 2 Mar 2017 19:24:43 +0530 > Vignesh R wrote: > >> > Not really, I am debugging another issue with UBIFS on DRA74 EVM (ARM > cortex-a15) wherein pages allocated by vmalloc are in highmem region > that are not addressable u

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-02 Thread Boris Brezillon
On Thu, 2 Mar 2017 19:24:43 +0530 Vignesh R wrote: > > >>> Not really, I am debugging another issue with UBIFS on DRA74 EVM (ARM > >>> cortex-a15) wherein pages allocated by vmalloc are in highmem region > >>> that are not addressable using 32 bit addresses and is backed by LPAE. > >>>

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-02 Thread Frode Isaksen
On 01/03/2017 17:55, Boris Brezillon wrote: > On Wed, 1 Mar 2017 17:16:30 +0530 > Vignesh R wrote: > >> On Wednesday 01 March 2017 04:13 PM, Cyrille Pitchen wrote: >>> Le 01/03/2017 à 05:54, Vignesh R a écrit : On Wednesday 01 March 2017 03:11 AM, Richard Weinberger wrote: > Vi

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-01 Thread Vignesh R

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-01 Thread Boris Brezillon
On Wed, 1 Mar 2017 17:16:30 +0530 Vignesh R wrote: > On Wednesday 01 March 2017 04:13 PM, Cyrille Pitchen wrote: > > Le 01/03/2017 à 05:54, Vignesh R a écrit : > >> > >> > >> On Wednesday 01 March 2017 03:11 AM, Richard Weinberger wrote: > >>> Vignesh, > >>> > >>> Am 27.02.2017 um 13:08 schri

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-01 Thread Boris Brezillon
On Wed, 1 Mar 2017 17:16:30 +0530 Vignesh R wrote: > On Wednesday 01 March 2017 04:13 PM, Cyrille Pitchen wrote: > > Le 01/03/2017 à 05:54, Vignesh R a écrit : > >> > >> > >> On Wednesday 01 March 2017 03:11 AM, Richard Weinberger wrote: > >>> Vignesh, > >>> > >>> Am 27.02.2017 um 13:08 schri

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-01 Thread Mark Brown
On Wed, Mar 01, 2017 at 03:21:24PM +0100, Cyrille Pitchen wrote: > Besides, some SPI controller drivers may already use their own bounce > buffer for other reasons. Then for those controllers, it would be one > more copy. They probably shouldn't, there's a lot of legacy drivers that do all sorts

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-01 Thread Boris Brezillon
On Wed, 1 Mar 2017 15:21:24 +0100 Cyrille Pitchen wrote: > + Mark > > Le 01/03/2017 à 12:46, Vignesh R a écrit : > > > > > > On Wednesday 01 March 2017 04:13 PM, Cyrille Pitchen wrote: > >> Le 01/03/2017 à 05:54, Vignesh R a écrit : > >>> > >>> > >>> On Wednesday 01 March 2017 03:11 AM, Ri

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-01 Thread Cyrille Pitchen
Le 01/03/2017 à 15:28, Boris Brezillon a écrit : > On Wed, 1 Mar 2017 15:21:24 +0100 > Cyrille Pitchen wrote: > >> + Mark >> >> Le 01/03/2017 à 12:46, Vignesh R a écrit : >>> >>> >>> On Wednesday 01 March 2017 04:13 PM, Cyrille Pitchen wrote: Le 01/03/2017 à 05:54, Vignesh R a écrit : >>

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-01 Thread Cyrille Pitchen
+ Mark Le 01/03/2017 à 12:46, Vignesh R a écrit : > > > On Wednesday 01 March 2017 04:13 PM, Cyrille Pitchen wrote: >> Le 01/03/2017 à 05:54, Vignesh R a écrit : >>> >>> >>> On Wednesday 01 March 2017 03:11 AM, Richard Weinberger wrote: Vignesh, Am 27.02.2017 um 13:08 schrieb Vign

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-01 Thread Boris Brezillon
On Wed, 1 Mar 2017 17:16:30 +0530 Vignesh R wrote: > On Wednesday 01 March 2017 04:13 PM, Cyrille Pitchen wrote: > > Le 01/03/2017 à 05:54, Vignesh R a écrit : > >> > >> > >> On Wednesday 01 March 2017 03:11 AM, Richard Weinberger wrote: > >>> Vignesh, > >>> > >>> Am 27.02.2017 um 13:08 schri

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-01 Thread Frode Isaksen
On 01/03/2017 11:43, Cyrille Pitchen wrote: > Le 01/03/2017 à 05:54, Vignesh R a écrit : >> >> On Wednesday 01 March 2017 03:11 AM, Richard Weinberger wrote: >>> Vignesh, >>> >>> Am 27.02.2017 um 13:08 schrieb Vignesh R: Many SPI controller drivers use DMA to read/write from m25p80 compatibl

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-03-01 Thread Cyrille Pitchen
Le 01/03/2017 à 05:54, Vignesh R a écrit : > > > On Wednesday 01 March 2017 03:11 AM, Richard Weinberger wrote: >> Vignesh, >> >> Am 27.02.2017 um 13:08 schrieb Vignesh R: >>> Many SPI controller drivers use DMA to read/write from m25p80 compatible >>> flashes. Therefore enable bounce buffers sup

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-02-28 Thread Vignesh R
On Wednesday 01 March 2017 03:11 AM, Richard Weinberger wrote: > Vignesh, > > Am 27.02.2017 um 13:08 schrieb Vignesh R: >> Many SPI controller drivers use DMA to read/write from m25p80 compatible >> flashes. Therefore enable bounce buffers support provided by spi-nor >> framework to take care of

Re: [RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-02-28 Thread Richard Weinberger
Vignesh, Am 27.02.2017 um 13:08 schrieb Vignesh R: > Many SPI controller drivers use DMA to read/write from m25p80 compatible > flashes. Therefore enable bounce buffers support provided by spi-nor > framework to take care of handling vmalloc'd buffers which may not be > DMA'able. > > Signed-off-b

[RFC PATCH 2/2] mtd: devices: m25p80: Enable spi-nor bounce buffer support

2017-02-27 Thread Vignesh R
Many SPI controller drivers use DMA to read/write from m25p80 compatible flashes. Therefore enable bounce buffers support provided by spi-nor framework to take care of handling vmalloc'd buffers which may not be DMA'able. Signed-off-by: Vignesh R --- drivers/mtd/devices/m25p80.c | 1 + 1 file ch