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

From: Marc Zyngier
Date: Tue Apr 20 2021 - 09:05:40 EST


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@xxxxxxxxxx>
Tested-by: Jon Hunter <jonathanh@xxxxxxxxxx>
Fixes: 973a28677e39 ("PCI: tegra: Convert to MSI domains")
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Thierry Reding <thierry.reding@xxxxxxxxx>
---
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