[U-Boot] [PATCH 2/3] bouncebuf: Add DMA validation check to addr_aligned().【请注意，邮件由u-boot-bounces at lists.denx.de代发】 addr_aligned().

[Simon Glass]

Hi,

On Thu, 4 Jul 2019 at 14:43, Heiko Stübner <heiko at sntech.de> wrote:
>
> Hi Simon,
>
> Am Dienstag, 4. Juni 2019, 05:23:14 CEST schrieb Kever Yang:
> > On 05/19/2019 12:08 AM, Simon Glass wrote:
> > > On Tue, 7 May 2019 at 03:05, Christoph Muellner
> > > <christoph.muellner at theobroma-systems.com> wrote:
> > >> Currently addr_aligned() performs an alignment and a length check
> > >> to validate the DMA address. However, some machines have stricter
> > >> restrictions of DMA-able addresses.
> > >>
> > >> This patch adds a call to mach_addr_is_dmaable() to honor this
> > >> machine specific restrictions.
> > >>
> > >> Signed-off-by: Christoph Muellner <christoph.muellner at theobroma-systems.com>
> > >> ---
> > >>
> > >>  common/bouncebuf.c | 6 ++++++
> > >>  1 file changed, 6 insertions(+)
> > > I feel like this should be handled with DM. Can we add a new method to
> > > the DMA uclass to check an address? If not provided by the DMA driver,
> > > we can assume the address is OK.
> >
> > The DMA in MMC controller which is not stand alone, do not using the
> > driver of DMA uclass, so I'm afraid this is not able to using DMA uclass
> > for this address check.
>
> were you able to consider Kever's response?
>
> The issue bites us for example when the mmc-driver with its internal dma
> does transfer atf loadables to the socs sram. There is no system dma
> controller involved but so far we're experiencing this on _all_ Rockchip
> socs that need multiple parts of the ATF be written to different memory
> locations. (the sram code is obviously needed for suspend/resume).

I don't really understand the thing about the internal MMC DMA controller.

Is it not possible to call a DMA driver to validate an address, or to
allocate an address? It isn't necessary to use the driver for a
transfer.

But if this is related to DMA, then it seems to me that the DMA uclass
should support the functionality, perhaps with a new method?

Regards,
Simon