dmaengine: bcm2835: Load driver early and support legacy API

Load driver early since at least bcm2708_fb doesn't support deferred
probing and even if it did, we don't want the video driver deferred.
Support the legacy DMA API which is needed by bcm2708_fb.
Don't mask out channel 2.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

bcm2835-dma: Add support for per-channel flags

Add the ability to interpret the high bits of the dreq specifier as
flags to be included in the DMA_CS register. The motivation for this
change is the ability to set the DISDEBUG flag for SD card transfers
to avoid corruption when using the VPU debugger.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>

bcm2835-dma: Add proper 40-bit DMA support

BCM2711 has 4 DMA channels with a 40-bit address range, allowing them
to access the full 4GB of memory on a Pi 4.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>

bcm2835-dma: Derive slave DMA addresses correctly

Slave addresses for DMA are meant to be supplied as physical addresses
(contrary to what struct snd_dmaengine_dai_dma_data does). It is up to
the DMA controller driver to perform the translation based on its own
view of the world, as described in Device Tree.

Now that the Pi Device Trees have the correct peripheral mappings,
replace the hacky address munging with phys_to_dma().

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

bcm2835-dma: Add NO_WAIT_RESP flag

Use bit 27 of the dreq value (the second cell of the DT DMA descriptor)
to request that the WAIT_RESP bit is not set.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

bcm2835-dma: Advertise the full DMA range

Unless the DMA mask is set wider than 32 bits, DMA mapping will use a
bounce buffer.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

bcm2835-dma: only reserve channel 0 if legacy dma driver is enabled

If CONFIG_DMA_BCM2708 isn't enabled there's no need to mask out
one of the already scarce DMA channels.

Signed-off-by: Matthias Reichl <hias@horus.com>

bcm2835-dma: Avoid losing CS flags after interrupt

Signed-off-by: Dom Cobley <popcornmix@gmail.com>

bcm2835-dma: Add bcm2835-dma: Add DMA_WIDE_SOURCE and DMA_WIDE_DEST flags

Use (reserved) bits 24 and 25 of the dreq value
(the second cell of the DT DMA descriptor) to request
that wide source reads or wide dest writes are required

Signed-off-by: Dom Cobley <popcornmix@gmail.com>

dmaengine: bcm2835: Fix position reporting for 40 bits channels

For 40 bits channels, the position is reported by reading the upper byte
in the SRCI/DESTI registers. However the driver adds that upper byte
with an 8-bits left shift, while it should be 32.

Fixes: 9a52a99 ("bcm2835-dma: Add proper 40-bit DMA support")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>

dmaengine: bcm2835: Use to_bcm2711_cbaddr where relevant

bcm2711_dma40_memcpy has some code strictly equivalent to the
to_bcm2711_cbaddr() function. Let's use it instead.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>

dmaengine: bcm2835: Fix descriptors usage for 40-bits channels

The bcm2835_dma_create_cb_chain() function is in charge of building up
the descriptors chain for a given transfer.

It was initially supporting only the BCM2835-style DMA controller, and
was later expanded to support controllers with 40-bits channels that use
a different descriptor layout.

However, some part of the function only use the old style descriptor,
even when building a chain of new-style descriptors, resulting in weird
bugs.

Fixes: 9a52a99 ("bcm2835-dma: Add proper 40-bit DMA support")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>

bcm2835-dma: Fix WAIT_RESP on memcpy

It goes in info not extra

Signed-off-by: Dom Cobley <popcornmix@gmail.com>

bcm2835-dma: Fix dma_abort for 40-bit channels

It wasn't aborting the transfer and caused stop/start
of hdmi audio dma to be unreliable.

New sequence approved by Broadcom.

Signed-off-by: Dom Cobley <popcornmix@gmail.com>

bcm2835-dma: Fix dma_abort for non-40bit channels

The sequence we were doing was not safe.

Clearing CS meant BCM2835_DMA_WAIT_FOR_WRITES was cleared
and so polling BCM2835_DMA_WAITING_FOR_WRITES has no benefit

Broadcom have provided a recommended sequence to abort
a dma lite channel, so switch to that.

Signed-off-by: Dom Cobley <popcornmix@gmail.com>

bcm2835-dma: Support dma flags for multi-beat burst

Add a control bit to enable a multi-beat burst on a DMA.
This improves DMA performance and is required for HDMI audio.

Signed-off-by: Dom Cobley <popcornmix@gmail.com>

bcm2835-dma: Need to keep PROT bits set in CS on 40bit controller

Resetting them to zero puts DMA channel into secure mode
which makes further accesses impossible

Signed-off-by: Dom Cobley <popcornmix@gmail.com>

dmaengine: bcm2835: Delete vestigial code

The dedicated dma40 memcpy code is no longer used, and without a
prototype the kernel build fails. Delete it.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

drivers/dma/Kconfig

@@ -136,7 +136,7 @@ config BCM_SBA_RAID
 
 config DMA_BCM2835
 	tristate "BCM2835 DMA engine support"
-	depends on ARCH_BCM2835
+	depends on ARCH_BCM2835 || ARCH_BCM2708 || ARCH_BCM2709
 	select DMA_ENGINE
 	select DMA_VIRTUAL_CHANNELS