linux-kernel - Re: [PATCH] PCI: tegra: Restore MSI enable state on resume

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Date:   Tue, 20 Apr 2021 14:16:05 +0100
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Marc Zyngier <maz@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
        kernel-team@...roid.com, Jon Hunter <jonathanh@...dia.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Thierry Reding <thierry.reding@...il.com>
Subject: Re: [PATCH] PCI: tegra: Restore MSI enable state on resume

On Tue, Apr 20, 2021 at 02:05:26PM +0100, Marc Zyngier wrote:
> When going into suspend, the Tegra MSI controller loses its
> state. Restore the MSI allocation on resume so that PCI devices
> are usable again.
> 
> Reported-by: Jon Hunter <jonathanh@...dia.com>
> Tested-by: Jon Hunter <jonathanh@...dia.com>
> Fixes: 973a28677e39 ("PCI: tegra: Convert to MSI domains")
> Signed-off-by: Marc Zyngier <maz@...nel.org>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
> Cc: Bjorn Helgaas <bhelgaas@...gle.com>
> Cc: Thierry Reding <thierry.reding@...il.com>
> ---
>  drivers/pci/controller/pci-tegra.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)

Squashed with the Fixes: commit, updated my pci/msi branch with it
and pushed out.

Thanks,
Lorenzo

> diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
> index eaba7b2fab4a..507b23d43ad1 100644
> --- a/drivers/pci/controller/pci-tegra.c
> +++ b/drivers/pci/controller/pci-tegra.c
> @@ -1802,13 +1802,19 @@ static void tegra_pcie_enable_msi(struct tegra_pcie *pcie)
>  {
>  	const struct tegra_pcie_soc *soc = pcie->soc;
>  	struct tegra_msi *msi = &pcie->msi;
> -	u32 reg;
> +	u32 reg, msi_state[INT_PCI_MSI_NR / 32];
> +	int i;
>  
>  	afi_writel(pcie, msi->phys >> soc->msi_base_shift, AFI_MSI_FPCI_BAR_ST);
>  	afi_writel(pcie, msi->phys, AFI_MSI_AXI_BAR_ST);
>  	/* this register is in 4K increments */
>  	afi_writel(pcie, 1, AFI_MSI_BAR_SZ);
>  
> +	/* Restore the MSI allocation state */
> +	bitmap_to_arr32(msi_state, msi->used, INT_PCI_MSI_NR);
> +	for (i = 0; i < ARRAY_SIZE(msi_state); i++)
> +		afi_writel(pcie, msi_state[i], AFI_MSI_EN_VEC(i));
> +
>  	/* and unmask the MSI interrupt */
>  	reg = afi_readl(pcie, AFI_INTR_MASK);
>  	reg |= AFI_INTR_MASK_MSI_MASK;
> -- 
> 2.30.2
>