On Thu, Apr 25, 2013 at 3:44 PM, Lee Jones <lee.jo...@linaro.org> wrote:
> On Thu, 25 Apr 2013, Linus Walleij wrote:
>> On Thu, Apr 18, 2013 at 12:27 PM, Lee Jones <lee.jo...@linaro.org> wrote:
>>
>> > The DMA controller currently takes configuration information from
>> > information passed though dma_channel_request(), but it shouldn't.
>> > Using the API, the DMA channel should only be configured during
>> > a dma_slave_config() call.
>> >
>> > Cc: Herbert Xu <herb...@gondor.apana.org.au>
>> > Cc: David S. Miller <da...@davemloft.net>
>> > Cc: Andreas Westin <andreas.wes...@stericsson.com>
>> > Cc: linux-crypto@vger.kernel.org
>> > Signed-off-by: Lee Jones <lee.jo...@linaro.org>
>>
>> (...)
>> > /* Cryp DMA interface */
>> > +#define HASH_DMA_TX_FIFO 0x08
>> > +#define HASH_DMA_RX_FIFO 0x10
>>
>> Yes, this is nice address notation :-)
>>
>> > /**
>> > * struct cryp_device_data - structure for a cryp device.
>> > - * @base: Pointer to the hardware base address.
>> > + * @base: Pointer to virtual base address of the cryp device.
>> > + * @phybase: Pointer to physical memory location of the cryp device.
>> > * @dev: Pointer to the devices dev structure.
>> > * @clk: Pointer to the device's clock control.
>> > * @pwr_regulator: Pointer to the device's power control.
>> > @@ -232,6 +236,7 @@ struct cryp_dma {
>> > */
>> > struct cryp_device_data {
>> > struct cryp_register __iomem *base;
>> > + phys_addr_t phybase;
>>
>> Use dma_addr_t. Maybe "phybase" is misleading,
>> "dmabase" is probably better. (Also applies to the
>> cryp patch).
>
> Accept it's not the dmabase.
>
> It's the phybase (U8500_CRYP1_BASE) i.e. the physical base address of
> the device's regs.
So when you assign the src_addr or dst_addr in struct
dmaengine_slave_config in this code,
you notice that this looks like so:
struct dma_slave_config {
enum dma_transfer_direction direction;
dma_addr_t src_addr;
dma_addr_t dst_addr;
enum dma_slave_buswidth src_addr_width;
enum dma_slave_buswidth dst_addr_width;
u32 src_maxburst;
u32 dst_maxburst;
bool device_fc;
};
So when you do this:
+ struct dma_slave_config mem2cryp = {
+ .direction = DMA_MEM_TO_DEV,
+ .dst_addr = device_data->phybase + HASH_DMA_TX_FIFO,
+ .dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES,
+ .dst_maxburst = 4,
+ };
on .dst_addr you are effectively casting a phys_addr_t
into a dma_addr_t.
But we must do this at some point, and now I think
that doing it here may be just as good (because we might
just add a physical-to-dma memory translation if need
be).
So allright.
Yours,
Linus Walleij
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