[PATCH v7] PCI: rockchip: Add Rockchip RK356X host controller driver

[Christoph Hellwig]

On Wed, Apr 28, 2021 at 09:42:37PM -0400, Peter Geis wrote:
> I have functional MSI support, some devices do not support MSIs
> however and need legacy INTx.
> I'd like to point out that the downstream patch does not actually work
> on downstream.
> The GFP_DMA32 flag is discarded by the slab allocator, this breaks MSI
> allocation when the PCIe driver probes.
> I hacked together my own version which works but would definitely not
> be accepted for submission.

Seriously folks.  Never, ever use GFP_DMA or GFP_DMA32 in actual driver
code.  They fundamentally don't do what you want.  Devices as a rule of
thumb do care about DMA addressability, not CPU addressability, so they
must use the DMA API to allocate the memory, and the dma mask to control
addressability.