[FSL P5020 P5040 PPC] Onboard SD card doesn't work anymore after the 'mmc-v5.4-2' updates

[Christian Zigotzky]

On 24 January 2020 at 12:42 pm, Michael Ellerman wrote:
> Ulf Hansson <ulf.hansson at linaro.org> writes:
>> On Thu, 16 Jan 2020 at 12:18, Christian Zigotzky <chzigotzky at xenosoft.de> wrote:
>>> Hi All,
>>>
>>> We still need the attached patch for our onboard SD card interface
>>> [1,2]. Could you please add this patch to the tree?
>> No, because according to previous discussion that isn't the correct
>> solution and more importantly it will break other archs (if I recall
>> correctly).
>>
>> Looks like someone from the ppc community needs to pick up the ball.
> That's a pretty small community these days :) :/
>
> Christian can you test this please? I think I got the polarity of all
> the tests right, but it's Friday night so maybe I'm wrong :)
>
> cheers
Michael,

Thanks a lot for the new patch! I compiled the RC7 of kernel 5.5 with 
your patch again yesterday and the kernel works without any problems 
with our onboard SD cards. [1]

Cheers,
Christian

[1] 
http://forum.hyperion-entertainment.com/viewtopic.php?f=58&t=4384&p=49697#p49693
>
> >From 975ba6e8b52d6f5358e93c1f5a47adc4a0b5fb70 Mon Sep 17 00:00:00 2001
> From: Michael Ellerman <mpe at ellerman.id.au>
> Date: Fri, 24 Jan 2020 22:26:59 +1100
> Subject: [PATCH] of: Add OF_DMA_DEFAULT_COHERENT & select it on powerpc
>
> There's an OF helper called of_dma_is_coherent(), which checks if a
> device has a "dma-coherent" property to see if the device is coherent
> for DMA.
>
> But on some platforms devices are coherent by default, and on some
> platforms it's not possible to update existing device trees to add the
> "dma-coherent" property.
>
> So add a Kconfig symbol to allow arch code to tell
> of_dma_is_coherent() that devices are coherent by default, regardless
> of the presence of the property.
>
> Select that symbol on powerpc when NOT_COHERENT_CACHE is not set, ie.
> when the system has a coherent cache.
>
> Fixes: 92ea637edea3 ("of: introduce of_dma_is_coherent() helper")
> Cc: stable at vger.kernel.org # v3.16+
> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
> ---
>   arch/powerpc/Kconfig | 1 +
>   drivers/of/Kconfig   | 4 ++++
>   drivers/of/address.c | 6 +++++-
>   3 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 62752c3bfabf..460678ab2375 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -235,6 +235,7 @@ config PPC
>   	select NEED_DMA_MAP_STATE		if PPC64 || NOT_COHERENT_CACHE
>   	select NEED_SG_DMA_LENGTH
>   	select OF
> +	select OF_DMA_DEFAULT_COHERENT		if !NOT_COHERENT_CACHE
>   	select OF_EARLY_FLATTREE
>   	select OLD_SIGACTION			if PPC32
>   	select OLD_SIGSUSPEND
> diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
> index 37c2ccbefecd..d91618641be6 100644
> --- a/drivers/of/Kconfig
> +++ b/drivers/of/Kconfig
> @@ -103,4 +103,8 @@ config OF_OVERLAY
>   config OF_NUMA
>   	bool
>   
> +config OF_DMA_DEFAULT_COHERENT
> +	# arches should select this if DMA is coherent by default for OF devices
> +	bool
> +
>   endif # OF
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index 99c1b8058559..e8a39c3ec4d4 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -995,12 +995,16 @@ int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *siz
>    * @np:	device node
>    *
>    * It returns true if "dma-coherent" property was found
> - * for this device in DT.
> + * for this device in the DT, or if DMA is coherent by
> + * default for OF devices on the current platform.
>    */
>   bool of_dma_is_coherent(struct device_node *np)
>   {
>   	struct device_node *node = of_node_get(np);
>   
> +	if (IS_ENABLED(CONFIG_OF_DMA_DEFAULT_COHERENT))
> +		return true;
> +
>   	while (node) {
>   		if (of_property_read_bool(node, "dma-coherent")) {
>   			of_node_put(node);