[PATCH v3 3/6] PCI: endpoint: Cleanup get_msi() callback

[Niklas Cassel]

The kdoc for pci_epc_get_msi() says:
"Invoke to get the number of MSI interrupts allocated by the RC"
the kdoc for the callback pci_epc_ops->get_msi() says:
"ops to get the number of MSI interrupts allocated by the RC from
the MSI capability register"

pci_epc_ops->get_msi() does however return the number of interrupts
in the encoding as defined by the MME Multiple Message Enable field.

Nowhere in the kdoc does it say that the returned number of interrupts
is in MME encoding.

Thus, it is very confusing that the wrapper function (pci_epc_get_msi())
and the callback function (pci_epc_ops->get_msi()) don't return the same
value.

Cleanup the API so that the wrapper function and the callback function
will have the same semantics, i.e. return the number of interrupts,
regardless of the internal encoding of that value.

Cc: <stable+noautosel at kernel.org> # this is simply a cleanup
Reviewed-by: Damien Le Moal <dlemoal at kernel.org>
Signed-off-by: Niklas Cassel <cassel at kernel.org>
---
 drivers/pci/controller/cadence/pcie-cadence-ep.c | 2 +-
 drivers/pci/controller/dwc/pcie-designware-ep.c  | 2 +-
 drivers/pci/controller/pcie-rcar-ep.c            | 2 +-
 drivers/pci/controller/pcie-rockchip-ep.c        | 4 ++--
 drivers/pci/endpoint/pci-epc-core.c              | 2 --
 5 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/controller/cadence/pcie-cadence-ep.c b/drivers/pci/controller/cadence/pcie-cadence-ep.c
index 112ae200b393..78b4d009cd04 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-ep.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c
@@ -262,7 +262,7 @@ static int cdns_pcie_ep_get_msi(struct pci_epc *epc, u8 fn, u8 vfn)
 	 */
 	mme = FIELD_GET(PCI_MSI_FLAGS_QSIZE, flags);
 
-	return mme;
+	return 1 << mme;
 }
 
 static int cdns_pcie_ep_get_msix(struct pci_epc *epc, u8 func_no, u8 vfunc_no)
diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 24026f3f3413..03597551f4cd 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -532,7 +532,7 @@ static int dw_pcie_ep_get_msi(struct pci_epc *epc, u8 func_no, u8 vfunc_no)
 
 	val = FIELD_GET(PCI_MSI_FLAGS_QSIZE, val);
 
-	return val;
+	return 1 << val;
 }
 
 static int dw_pcie_ep_set_msi(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
diff --git a/drivers/pci/controller/pcie-rcar-ep.c b/drivers/pci/controller/pcie-rcar-ep.c
index c5e0d025bc43..9da39a4617b6 100644
--- a/drivers/pci/controller/pcie-rcar-ep.c
+++ b/drivers/pci/controller/pcie-rcar-ep.c
@@ -280,7 +280,7 @@ static int rcar_pcie_ep_get_msi(struct pci_epc *epc, u8 fn, u8 vfn)
 	if (!(flags & MSICAP0_MSIE))
 		return -EINVAL;
 
-	return ((flags & MSICAP0_MMESE_MASK) >> MSICAP0_MMESE_OFFSET);
+	return 1 << ((flags & MSICAP0_MMESE_MASK) >> MSICAP0_MMESE_OFFSET);
 }
 
 static int rcar_pcie_ep_map_addr(struct pci_epc *epc, u8 fn, u8 vfn,
diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index 85ea36df2f59..85ca7d9b4c77 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -340,8 +340,8 @@ static int rockchip_pcie_ep_get_msi(struct pci_epc *epc, u8 fn, u8 vfn)
 	if (!(flags & ROCKCHIP_PCIE_EP_MSI_CTRL_ME))
 		return -EINVAL;
 
-	return ((flags & ROCKCHIP_PCIE_EP_MSI_CTRL_MME_MASK) >>
-			ROCKCHIP_PCIE_EP_MSI_CTRL_MME_OFFSET);
+	return 1 << ((flags & ROCKCHIP_PCIE_EP_MSI_CTRL_MME_MASK) >>
+		     ROCKCHIP_PCIE_EP_MSI_CTRL_MME_OFFSET);
 }
 
 static void rockchip_pcie_ep_assert_intx(struct rockchip_pcie_ep *ep, u8 fn,
diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index beabea00af91..cc1456bd188e 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -293,8 +293,6 @@ int pci_epc_get_msi(struct pci_epc *epc, u8 func_no, u8 vfunc_no)
 	if (interrupt < 0)
 		return 0;
 
-	interrupt = 1 << interrupt;
-
 	return interrupt;
 }
 EXPORT_SYMBOL_GPL(pci_epc_get_msi);
-- 
2.49.0