Re: [RFT PATCH v3 12/27] of/address: Add infrastructure to declare MMIO as non-posted
From: Linus Walleij <hidden>
Date: 2021-03-09 15:41:00
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linux-arch, linux-devicetree, linux-doc, linux-samsung-soc, linux-serial, lkml
On Tue, Mar 9, 2021 at 1:41 PM Arnd Bergmann [off-list ref] wrote:
- A driver writer may want to choose between posted and nonposted mmio based on performance considerations: if writes are never serialized, posted writes should always be faster. However, if the driver uses a spinlock to serialize writes, then a nonposted write is likely faster than a posted write followed by a read that serializes the spin_unlock. In this case we want the driver to explicitly pick one over the other, and not have rely on bus specific magic.
OK then I am all for having drivers explicitly choose access method. Openness to speed optimization is a well established Linux kernel design principle. Yours, Linus Walleij _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel