PCI: dwc: Fix scheduling while atomic issues

Jisheng Zhang · bjorn-helgaas · commit 9024143e700f · 2018-09-20T16:36:20.000-05:00
When programming the inbound/outbound ATUs, we call usleep_range() after each checking PCIE_ATU_ENABLE bit. Unfortunately, the ATU programming can be executed in atomic context: inbound ATU programming could be called through pci_epc_write_header() =>dw_pcie_ep_write_header() =>dw_pcie_prog_inbound_atu() outbound ATU programming could be called through pci_bus_read_config_dword() =>dw_pcie_rd_conf() =>dw_pcie_prog_outbound_atu() Fix this issue by calling mdelay() instead. Fixes: f8aed6e ("PCI: dwc: designware: Add EP mode support") Fixes: d8bbeb3 ("PCI: designware: Wait for iATU enable") Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> [lorenzo.pieralisi@arm.com: commit log update] Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
@@ -135,7 +135,7 @@ static void dw_pcie_prog_outbound_atu_unroll(struct dw_pcie *pci, int index,
 		if (val & PCIE_ATU_ENABLE)
 			return;
 
-		usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);
+		mdelay(LINK_WAIT_IATU);
 	}
 	dev_err(pci->dev, "Outbound iATU is not being enabled\n");
 }
@@ -178,7 +178,7 @@ void dw_pcie_prog_outbound_atu(struct dw_pcie *pci, int index, int type,
 		if (val & PCIE_ATU_ENABLE)
 			return;
 
-		usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);
+		mdelay(LINK_WAIT_IATU);
 	}
 	dev_err(pci->dev, "Outbound iATU is not being enabled\n");
 }
@@ -236,7 +236,7 @@ static int dw_pcie_prog_inbound_atu_unroll(struct dw_pcie *pci, int index,
 		if (val & PCIE_ATU_ENABLE)
 			return 0;
 
-		usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);
+		mdelay(LINK_WAIT_IATU);
 	}
 	dev_err(pci->dev, "Inbound iATU is not being enabled\n");
 
@@ -282,7 +282,7 @@ int dw_pcie_prog_inbound_atu(struct dw_pcie *pci, int index, int bar,
 		if (val & PCIE_ATU_ENABLE)
 			return 0;
 
-		usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);
+		mdelay(LINK_WAIT_IATU);
 	}
 	dev_err(pci->dev, "Inbound iATU is not being enabled\n");
 
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
@@ -26,8 +26,7 @@
 
 /* Parameters for the waiting for iATU enabled routine */
 #define LINK_WAIT_MAX_IATU_RETRIES	5
-#define LINK_WAIT_IATU_MIN		9000
-#define LINK_WAIT_IATU_MAX		10000
+#define LINK_WAIT_IATU			9
 
 /* Synopsys-specific PCIe configuration registers */
 #define PCIE_PORT_LINK_CONTROL		0x710

Original file line number	Diff line number	Diff line change
`@@ -135,7 +135,7 @@ static void dw_pcie_prog_outbound_atu_unroll(struct dw_pcie *pci, int index,`
`135`	`135`	`if (val & PCIE_ATU_ENABLE)`
`136`	`136`	`return;`
`137`	`137`
`138`		`- usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);`
	`138`	`+ mdelay(LINK_WAIT_IATU);`
`139`	`139`	`}`
`140`	`140`	`dev_err(pci->dev, "Outbound iATU is not being enabled\n");`
`141`	`141`	`}`
`@@ -178,7 +178,7 @@ void dw_pcie_prog_outbound_atu(struct dw_pcie *pci, int index, int type,`
`178`	`178`	`if (val & PCIE_ATU_ENABLE)`
`179`	`179`	`return;`
`180`	`180`
`181`		`- usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);`
	`181`	`+ mdelay(LINK_WAIT_IATU);`
`182`	`182`	`}`
`183`	`183`	`dev_err(pci->dev, "Outbound iATU is not being enabled\n");`
`184`	`184`	`}`
`@@ -236,7 +236,7 @@ static int dw_pcie_prog_inbound_atu_unroll(struct dw_pcie *pci, int index,`
`236`	`236`	`if (val & PCIE_ATU_ENABLE)`
`237`	`237`	`return 0;`
`238`	`238`
`239`		`- usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);`
	`239`	`+ mdelay(LINK_WAIT_IATU);`
`240`	`240`	`}`
`241`	`241`	`dev_err(pci->dev, "Inbound iATU is not being enabled\n");`
`242`	`242`
`@@ -282,7 +282,7 @@ int dw_pcie_prog_inbound_atu(struct dw_pcie *pci, int index, int bar,`
`282`	`282`	`if (val & PCIE_ATU_ENABLE)`
`283`	`283`	`return 0;`
`284`	`284`
`285`		`- usleep_range(LINK_WAIT_IATU_MIN, LINK_WAIT_IATU_MAX);`
	`285`	`+ mdelay(LINK_WAIT_IATU);`
`286`	`286`	`}`
`287`	`287`	`dev_err(pci->dev, "Inbound iATU is not being enabled\n");`
`288`	`288`