linux-kernel - [PATCH v2 06/17] PCI: designware-ep: Add generic function for raising MSI irq

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Date:   Mon, 30 Oct 2017 13:42:09 +0100
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 v2 06/17] PCI: designware-ep: Add generic function for raising MSI irq

This function can be used by all DWC based controllers to raise a MSI
irq. However, certain controllers, like DRA7xx, has a special
convenience register for raising MSI irqs that doesn't require you to
explicitly map the MSI address.

Signed-off-by: Niklas Cassel <niklas.cassel@...s.com>
---
V2:
* New patch in this series. The other changes in the changelog are against
  the version that was included in pcie-artpec6.c in V1.
* raise_msi_irq now uses readw/writew instead of masking.
* raise_msi_irq now uses fixed offset for MSI cap in raise_msi, since it is
  always at the same offset for this IP.
* raise_msi_irq now uses PCI_MSI_FLAGS_64BIT rather than BIT(7).

 drivers/pci/dwc/pcie-designware-ep.c | 34 ++++++++++++++++++++++++++++++++++
 drivers/pci/dwc/pcie-designware.h    |  9 +++++++++
 2 files changed, 43 insertions(+)

diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-designware-ep.c
index 47134a85a342..92b7ca36bae4 100644
--- a/drivers/pci/dwc/pcie-designware-ep.c
+++ b/drivers/pci/dwc/pcie-designware-ep.c
@@ -282,6 +282,40 @@ static const struct pci_epc_ops epc_ops = {
 	.stop			= dw_pcie_ep_stop,
 };
 
+int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep,
+			     u8 interrupt_num)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
+	struct pci_epc *epc = ep->epc;
+	u16 msg_ctrl, msg_data;
+	u32 msg_addr_lower, msg_addr_upper;
+	u64 msg_addr;
+	bool has_upper;
+	int ret;
+
+	/* Raise MSI per the PCI Local Bus Specification Revision 3.0, 6.8.1. */
+	msg_ctrl = dw_pcie_readw_dbi(pci, MSI_MESSAGE_CONTROL);
+	has_upper = !!(msg_ctrl & PCI_MSI_FLAGS_64BIT);
+	msg_addr_lower = dw_pcie_readl_dbi(pci, MSI_MESSAGE_ADDR_L32);
+	if (has_upper) {
+		msg_addr_upper = dw_pcie_readl_dbi(pci, MSI_MESSAGE_ADDR_U32);
+		msg_data = dw_pcie_readw_dbi(pci, MSI_MESSAGE_DATA_64);
+	} else {
+		msg_addr_upper = 0;
+		msg_data = dw_pcie_readw_dbi(pci, MSI_MESSAGE_DATA_32);
+	}
+	msg_addr = ((u64) msg_addr_upper) << 32 | msg_addr_lower;
+	ret = dw_pcie_ep_map_addr(epc, ep->msi_mem_phys, msg_addr, PAGE_SIZE);
+	if (ret)
+		return ret;
+
+	writel(msg_data | (interrupt_num - 1), ep->msi_mem);
+
+	dw_pcie_ep_unmap_addr(epc, ep->msi_mem_phys);
+
+	return 0;
+}
+
 void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
 {
 	struct pci_epc *epc = ep->epc;
diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h
index 37dfad8d003f..24edac035160 100644
--- a/drivers/pci/dwc/pcie-designware.h
+++ b/drivers/pci/dwc/pcie-designware.h
@@ -106,6 +106,8 @@
 #define MSI_CAP_MME_MASK		(7 << MSI_CAP_MME_SHIFT)
 #define MSI_MESSAGE_ADDR_L32		0x54
 #define MSI_MESSAGE_ADDR_U32		0x58
+#define MSI_MESSAGE_DATA_32		0x58
+#define MSI_MESSAGE_DATA_64		0x5C
 
 /*
  * Maximum number of MSI IRQs can be 256 per controller. But keep
@@ -338,6 +340,7 @@ static inline int dw_pcie_host_init(struct pcie_port *pp)
 void dw_pcie_ep_linkup(struct dw_pcie_ep *ep);
 int dw_pcie_ep_init(struct dw_pcie_ep *ep);
 void dw_pcie_ep_exit(struct dw_pcie_ep *ep);
+int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 interrupt_num);
 void dw_pcie_ep_reset_bar(struct dw_pcie *pci, enum pci_barno bar);
 #else
 static inline void dw_pcie_ep_linkup(struct dw_pcie_ep *ep)
@@ -353,6 +356,12 @@ static inline void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
 {
 }
 
+static inline int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep,
+					   u8 interrupt_num)
+{
+	return 0;
+}
+
 static inline void dw_pcie_ep_reset_bar(struct dw_pcie *pci, enum pci_barno bar)
 {
 }
-- 
2.14.2