[PATCHv3] arm64: gic-v3-its: Clear the Pending table before enabling LPIs
wasim.khan at nxp.com
Tue Mar 30 08:18:14 CEST 2021
> -----Original Message-----
> From: U-Boot <u-boot-bounces at lists.denx.de> On Behalf Of Zhiqiang Hou
> Sent: Friday, March 5, 2021 12:33 PM
> To: u-boot at lists.denx.de
> Cc: sjg at chromium.org; rayagonda.kokatanur at broadcom.com; Priyanka Jain
> <priyanka.jain at nxp.com>; Z.q. Hou <zhiqiang.hou at nxp.com>
> Subject: [PATCHv3] arm64: gic-v3-its: Clear the Pending table before enabling
> From: Hou Zhiqiang <Zhiqiang.Hou at nxp.com>
> The GICv3 RM requires "The first 1KB of memory for the LPI Pending tables must
> contain only zeros on initial allocation, and this must be visible to the
> Redistributors, or else the effect is UNPREDICTABLE".
> And as the following statement, we here clear the whole Pending tables instead
> of the first 1KB.
> "An LPI Pending table that contains only zeros, including in the first 1KB,
> indicates that there are no pending LPIs.
> The first 1KB of the LPI Pending table is IMPLEMENTATION DEFINED. However,
> if the first 1KB of the LPI Pending table and the rest of the table contain only
> zeros, this must indicate that there are no pending LPIs."
> And there isn't any pending LPI under U-Boot, so it's unnecessary to load the
> contents of the Pending table during the enablement, then set the
> GICR_PENDBASER.PTZ flag.
> Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou at nxp.com>
> - Fix a mistake code delete in v2.
Reviewed-by: Wasim Khan <wasim.khan at nxp.com>
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