linux-kernel - [PATCH v4 4/5] PCI: endpoint: Make pci_epc_set_bar() return the BAR width that was set-up

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Date:   Thu,  8 Mar 2018 14:33:29 +0100
From:   Niklas Cassel <niklas.cassel@...s.com>
To:     kishon@...com, Alan Douglas <adouglas@...ence.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Jingoo Han <jingoohan1@...il.com>,
        Joao Pinto <Joao.Pinto@...opsys.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Sekhar Nori <nsekhar@...com>,
        Shawn Lin <shawn.lin@...k-chips.com>,
        Niklas Cassel <niklass@...s.com>,
        Cyrille Pitchen <cyrille.pitchen@...e-electrons.com>
Cc:     Niklas Cassel <niklass@...s.com>, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4 4/5] PCI: endpoint: Make pci_epc_set_bar() return the BAR width that was set-up

In order to properly handle 64-bit BARs, we need to know what BAR width
that was actually set-up by specific pci_epc_set_bar() implementations.

This is done so that we can know if we need to skip a BAR,
since a 64-bit BAR consists of a BAR pair.

It is important to know the BAR width that was actually set-up,
since some drivers, like the Cadence EP controller, does not
simply look at PCI_BASE_ADDRESS_MEM_TYPE_64, as it configures
all BARs larger than 2G as 64-bit.

Signed-off-by: Niklas Cassel <niklas.cassel@...s.com>
---
 drivers/pci/cadence/pcie-cadence-ep.c         | 2 +-
 drivers/pci/dwc/pcie-designware-ep.c          | 4 ++--
 drivers/pci/endpoint/functions/pci-epf-test.c | 7 ++++++-
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/cadence/pcie-cadence-ep.c b/drivers/pci/cadence/pcie-cadence-ep.c
index 3c3a97743453..0e4cc4cca56d 100644
--- a/drivers/pci/cadence/pcie-cadence-ep.c
+++ b/drivers/pci/cadence/pcie-cadence-ep.c
@@ -135,7 +135,7 @@ static int cdns_pcie_ep_set_bar(struct pci_epc *epc, u8 fn, enum pci_barno bar,
 		CDNS_PCIE_LM_EP_FUNC_BAR_CFG_BAR_CTRL(b, ctrl));
 	cdns_pcie_writel(pcie, reg, cfg);
 
-	return 0;
+	return is_64bits ? 1 : 0;
 }
 
 static void cdns_pcie_ep_clear_bar(struct pci_epc *epc, u8 fn,
diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-designware-ep.c
index b20b2651caf9..f3c19f8ff8e5 100644
--- a/drivers/pci/dwc/pcie-designware-ep.c
+++ b/drivers/pci/dwc/pcie-designware-ep.c
@@ -139,7 +139,7 @@ static int dw_pcie_ep_set_bar(struct pci_epc *epc, u8 func_no,
 		as_type = DW_PCIE_AS_IO;
 
 	ret = dw_pcie_ep_inbound_atu(ep, bar, bar_phys, as_type);
-	if (ret)
+	if (ret < 0)
 		return ret;
 
 	dw_pcie_dbi_ro_wr_en(pci);
@@ -154,7 +154,7 @@ static int dw_pcie_ep_set_bar(struct pci_epc *epc, u8 func_no,
 	}
 	dw_pcie_dbi_ro_wr_dis(pci);
 
-	return 0;
+	return (flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ? 1 : 0;
 }
 
 static int dw_pcie_find_index(struct dw_pcie_ep *ep, phys_addr_t addr,
diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 7c70433b11a7..09878e011284 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -379,12 +379,17 @@ static int pci_epf_test_set_bar(struct pci_epf *epf)
 		ret = pci_epc_set_bar(epc, epf->func_no, bar,
 				      epf_bar->phys_addr,
 				      epf_bar->size, bar_flags[bar]);
-		if (ret) {
+		if (ret < 0) {
 			pci_epf_free_space(epf, epf_test->reg[bar], bar);
 			dev_err(dev, "failed to set BAR%d\n", bar);
 			if (bar == test_reg_bar)
 				return ret;
 		}
+		/*
+		 * pci_epc_set_bar() returns 1 if a 64-bit BAR was set-up,
+		 * or 0 if a 32-bit BAR was set-up.
+		 */
+		bar += ret;
 	}
 
 	return 0;
-- 
2.14.2