[PATCH] PCI: tegra: Restore MSI enable state on resume

[Marc Zyngier <maz@kernel.org>]

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@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Fixes: 973a28677e39 ("PCI: tegra: Convert to MSI domains")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
---
 drivers/pci/controller/pci-tegra.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

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