Re: [PATCH] dm: Respect dma-ranges size

Marek Vasut
2026-03-30T21:07:56Z

On 3/30/26 3:34 PM, Markus Schneider-Pargmann wrote:

Hello Markus,

> On Mon Mar 16, 2026 at 12:57 AM CET, Marek Vasut wrote:
>> Rework dev_phys_to_bus() and dev_bus_to_phys() to respect the size
>> of the area specified in dma-ranges DT property. The area outside
>> of ranges is remapped 1:1, while the area in the ranges is remapped
>> according to the description in the dma-ranges property.
>>
>> Adjust the test to test the area within the remapped range, not area
>> outside the remapped range, which was incorrect.
>>
>
> Should this have a Fixes tag?
>
>> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
>
> Not a big expert, but this looks good to me:
>
> Reviewed-by: Markus Schneider-Pargmann <msp@baylibre.com>

This was broken long enough, so this should go into next so it would get
sufficient testing before the next release.

[...]

>> +++ b/include/dm/device.h
>> @@ -166,8 +166,9 @@ enum {
>> * When CONFIG_DEVRES is enabled, devm_kmalloc() and friends will
>> * add to this list. Memory so-allocated will be freed
>> * automatically when the device is removed / unbound
>> - * @dma_offset: Offset between the physical address space (CPU's) and the
>> - * device's bus address space
>> + * @dma_cpu: DMA physical address space (CPU's)
>> + * @dma_bus: DMA device's bus address space
>> + * @dma_size: DMA window size
>> * @iommu: IOMMU device associated with this device
>> */
>> struct udevice {
>> @@ -196,7 +197,9 @@ struct udevice {
>> struct list_head devres_head;
>> #endif
>> #if CONFIG_IS_ENABLED(DM_DMA)
>> - ulong dma_offset;
>> + phys_addr_t dma_cpu;
>> + dma_addr_t dma_bus;
>> + u64 dma_size;
>> #endif

[...]

>> +++ b/include/phys2bus.h
>> @@ -21,17 +21,23 @@ static inline unsigned long bus_to_phys(unsigned long bus)
>> }
>> #endif
>>
>> -#if CONFIG_IS_ENABLED(DM)
>> +#if CONFIG_IS_ENABLED(DM_DMA)
>
> This is not related to the code changes right?

It is, see the matching hunk above and below why this is guarded by DM_DMA .

>> #include <dm/device.h>
>>
>> static inline dma_addr_t dev_phys_to_bus(struct udevice *dev, phys_addr_t phys)
>> {
>> - return phys - dev_get_dma_offset(dev);
>> + /* If the PA is in the remap range, apply remap. */
>> + if (phys >= dev->dma_cpu && phys < dev->dma_cpu + dev->dma_size)
>> + phys -= dev->dma_cpu - dev->dma_bus;
>> + return phys; …