Re: [PATCH 1/7] irqchip/gic-v3: Add a DMA Non-Coherent flag
From: Peter Geis <hidden>
Date: 2023-03-10 12:04:35
Also in:
linux-devicetree, linux-pci, linux-phy, linux-rockchip, lkml
On Fri, Mar 10, 2023 at 6:57 AM Marc Zyngier [off-list ref] wrote:
On Fri, 10 Mar 2023 11:41:46 +0000, Peter Geis [off-list ref] wrote:quoted
On Fri, Mar 10, 2023 at 3:05 AM Lucas Tanure [off-list ref] wrote:quoted
The GIC600 integration in RK356x, used in rk3588, doesn't support any of the shareability or cacheability attributes, and requires both values to be set to 0b00 for all the ITS and Redistributor tables. This is loosely based on prior work from XiaoDong Huang and Peter Geis fixing this issue specifically for Rockchip 356x.Good Morning, Since the gic is using dma, would it be reasonable to have all memory allocations be requested with the GFP_DMA flag? Otherwise this doesn't fully solve the problem for rk356x, where only the lower 4GB range is DMA capable, but this tends to get allocated in the upper 4GB on 8GB boards.That's an erratum. Please treat as such.
Good Morning, Yes, believe me I'm fully aware of how broken rk356x is. I'm asking an educational question from a kernel standards point of view, absent the rk356x issues. Would it be reasonable that since the gic uses dma memory, allocations for the gic should be made with the GFP_DMA flag? Or is that a misuse of the flag? Very Respectfully, Peter Geis
M.
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