linux-kernel - [PATCH 02/10] PCI: designware-ep: set

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Date:   Fri, 13 Oct 2017 18:09:05 +0200
From:   Niklas Cassel <niklas.cassel@...s.com>
To:     Jingoo Han <jingoohan1@...il.com>,
        Joao Pinto <Joao.Pinto@...opsys.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>
Cc:     Niklas Cassel <niklass@...s.com>, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 02/10] PCI: designware-ep: set_msi should only set MMC bits

Previously, set_msi wrote all bits in the Message Control
register, thus overwriting the 64 bit address capable bit.
By clearing the 64 bit address capable bit, we break MSI
on systems where the RC has set a 64 bit MSI address.

Signed-off-by: Niklas Cassel <niklas.cassel@...s.com>
---
 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 d53d5f168363..c92ab87fd660 100644
--- a/drivers/pci/dwc/pcie-designware-ep.c
+++ b/drivers/pci/dwc/pcie-designware-ep.c
@@ -220,7 +220,9 @@ 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 547352a317f8..36183906e1d2 100644
--- a/drivers/pci/dwc/pcie-designware.h
+++ b/drivers/pci/dwc/pcie-designware.h
@@ -101,6 +101,7 @@
 
 #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_MME_MASK		(7 << MSI_CAP_MME_SHIFT)
 #define MSI_MESSAGE_ADDR_L32		0x54
-- 
2.11.0