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Subject[BACKPORT 4.14.y 2/8] PCI: designware-ep: dw_pcie_ep_set_msi() should only set MMC bits
Date
From: Niklas Cassel <niklas.cassel@axis.com>

Previously, dw_pcie_ep_set_msi() wrote all bits in the Message Control
register, thus overwriting the PCI_MSI_FLAGS_64BIT bit.
By clearing the PCI_MSI_FLAGS_64BIT bit, we break MSI
on systems where the RC has set a 64 bit MSI address.
Fix dw_pcie_ep_set_msi() so that it only sets MMC bits.

Tested-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Joao Pinto <jpinto@synopsys.com>
(cherry picked from commit 099a95f3591ade29da52131895a3ba9f92a0e82c)
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/pci/dwc/pcie-designware-ep.c | 4 +++-
drivers/pci/dwc/pcie-designware.h | 1 +
2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-designware-ep.c
index 7c621877a939..df317d390317 100644
--- a/drivers/pci/dwc/pcie-designware-ep.c
+++ b/drivers/pci/dwc/pcie-designware-ep.c
@@ -214,7 +214,9 @@ static int dw_pcie_ep_set_msi(struct pci_epc *epc, u8 encode_int)
struct dw_pcie_ep *ep = epc_get_drvdata(epc);
struct dw_pcie *pci = to_dw_pcie_from_ep(ep);

- val = (encode_int << MSI_CAP_MMC_SHIFT);
+ val = dw_pcie_readw_dbi(pci, MSI_MESSAGE_CONTROL);
+ val &= ~MSI_CAP_MMC_MASK;
+ val |= (encode_int << MSI_CAP_MMC_SHIFT) & MSI_CAP_MMC_MASK;
dw_pcie_writew_dbi(pci, MSI_MESSAGE_CONTROL, val);

return 0;
diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h
index 3551dd607b90..5af29d125c7e 100644
--- a/drivers/pci/dwc/pcie-designware.h
+++ b/drivers/pci/dwc/pcie-designware.h
@@ -99,6 +99,7 @@

#define MSI_MESSAGE_CONTROL 0x52
#define MSI_CAP_MMC_SHIFT 1
+#define MSI_CAP_MMC_MASK (7 << MSI_CAP_MMC_SHIFT)
#define MSI_CAP_MME_SHIFT 4
#define MSI_CAP_MSI_EN_MASK 0x1
#define MSI_CAP_MME_MASK (7 << MSI_CAP_MME_SHIFT)
--
2.20.0
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