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SubjectRe: [PATCH] mmc: sdhci-of-esdhc: set proper dma mask for ls104x chips
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Hi Uffe,

On 02.07.2018 17:37, Ulf Hansson wrote:
> On 28 June 2018 at 10:45, Laurentiu Tudor <laurentiu.tudor@nxp.com> wrote:
>> SDHCI controller in ls1043a and ls1046a generate 40-bit wide addresses
>> when doing DMA. Make sure that the corresponding dma mask is correctly
>> configured.
>>
>> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
>
> Thanks, applied for next!

Thanks for picking this up!
I just realized that maybe I should have provided some context around
this patch. I'm working on enabling smmu on these chips and encountered
the following problem: the smmu input address size is 48 bits so the dma
mappings for sdhci end up 48-bit wide. However, on these chips sdhci
only use 40-bits of that address size when doing dma.
So you end up with a 48-bit address translation in smmu but the device
generates transactions with clipped 40-bit addresses, thus smmu context
faults are triggered. Setting up the correct dma mask fixes this situation.

---
Best Regards, Laurentiu

>
>> ---
>> drivers/mmc/host/sdhci-of-esdhc.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-of-esdhc.c
>> index 4ffa6b173a21..8332f56e6c0d 100644
>> --- a/drivers/mmc/host/sdhci-of-esdhc.c
>> +++ b/drivers/mmc/host/sdhci-of-esdhc.c
>> @@ -22,6 +22,7 @@
>> #include <linux/sys_soc.h>
>> #include <linux/clk.h>
>> #include <linux/ktime.h>
>> +#include <linux/dma-mapping.h>
>> #include <linux/mmc/host.h>
>> #include "sdhci-pltfm.h"
>> #include "sdhci-esdhc.h"
>> @@ -427,6 +428,11 @@ static void esdhc_of_adma_workaround(struct sdhci_host *host, u32 intmask)
>> static int esdhc_of_enable_dma(struct sdhci_host *host)
>> {
>> u32 value;
>> + struct device *dev = mmc_dev(host->mmc);
>> +
>> + if (of_device_is_compatible(dev->of_node, "fsl,ls1043a-esdhc") ||
>> + of_device_is_compatible(dev->of_node, "fsl,ls1046a-esdhc"))
>> + dma_set_mask_and_coherent(dev, DMA_BIT_MASK(40));
>>
>> value = sdhci_readl(host, ESDHC_DMA_SYSCTL);
>> value |= ESDHC_DMA_SNOOP;
>> --
>> 2.17.1
>>
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