linux-kernel - Re: [PATCH 2/3] PCI: iproc: fix invalidating PAXB address mapping

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Message-ID: <20200326152818.GA7634@google.com>
Date:   Thu, 26 Mar 2020 10:28:18 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Srinath Mannam <srinath.mannam@...adcom.com>
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Ray Jui <rjui@...adcom.com>,
        Andrew Murray <amurray@...goodpenguin.co.uk>,
        bcm-kernel-feedback-list@...adcom.com, linux-pci@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Roman Bacik <roman.bacik@...adcom.com>
Subject: Re: [PATCH 2/3] PCI: iproc: fix invalidating PAXB address mapping

[fixed Andrew's email addr]

Change subject to match convention, e.g.,

  PCI: iproc: Invalidate correct PAXB inbound windows

On Thu, Mar 26, 2020 at 12:37:26PM +0530, Srinath Mannam wrote:
> From: Roman Bacik <roman.bacik@...adcom.com>
> 
> Second stage bootloader prior to Linux boot may use all inbound windows
> including IARR1/IMAP1. We need to ensure all previous configuration of
> inbound windows are invalidated during the initialization stage of the
> Linux iProc PCIe driver. Add fix to invalidate IARR1/IMAP1 because it was
> missed in previous patch.
> 
> Fixes: 9415743e4c8a ("PCI: iproc: Invalidate PAXB address mapping")
> Signed-off-by: Roman Bacik <roman.bacik@...adcom.com>
> ---
>  drivers/pci/controller/pcie-iproc.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/pci/controller/pcie-iproc.c b/drivers/pci/controller/pcie-iproc.c
> index 6972ca4..e7f0d58 100644
> --- a/drivers/pci/controller/pcie-iproc.c
> +++ b/drivers/pci/controller/pcie-iproc.c
> @@ -351,6 +351,8 @@ static const u16 iproc_pcie_reg_paxb_v2[IPROC_PCIE_MAX_NUM_REG] = {
>  	[IPROC_PCIE_OMAP3]		= 0xdf8,
>  	[IPROC_PCIE_IARR0]		= 0xd00,
>  	[IPROC_PCIE_IMAP0]		= 0xc00,
> +	[IPROC_PCIE_IARR1]		= 0xd08,
> +	[IPROC_PCIE_IMAP1]		= 0xd70,

Wow, this is a little too subtle for my taste.

9415743e4c8a added this loop:

  +   for (idx = 0; idx < ib->nr_regions; idx++) {
  +       iproc_pcie_write_reg(pcie,
  +                            MAP_REG(IPROC_PCIE_IARR0, idx), 0);

This patch doesn't change the loop or the limit, so I *guess*
previously we invalidated IPROC_PCIE_IARR0, IPROC_PCIE_IARR2, ...,
(skipping IPROC_PCIE_IARR1), and now we will invalidate
IPROC_PCIE_IARR0, IPROC_PCIE_IARR1, ... instead?

>  	[IPROC_PCIE_IARR2]		= 0xd10,
>  	[IPROC_PCIE_IMAP2]		= 0xcc0,
>  	[IPROC_PCIE_IARR3]		= 0xe00,