[PATCH AUTOSEL 4.14 22/32] PCI: dwc: Fix scheduling while atomic issues

Sasha Levin
2018-10-08T15:26:55Z

From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

[ Upstream commit 9024143e700f89d74b8cdaf316a3499d74fc56fe ]

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: f8aed6ec624f ("PCI: dwc: designware: Add EP mode support")
Fixes: d8bbeb39fbf3 ("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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/pci/dwc/pcie-designware.c | 8 ++++----
drivers/pci/dwc/pcie-designware.h | 3 +--
2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/dwc/pcie-designware.c b/drivers/pci/dwc/pcie-designware.c
index 88abdddee2ad..a06ad2c65174 100644
--- a/drivers/pci/dwc/pcie-designware.c
+++ b/drivers/pci/dwc/pcie-designware.c
@@ -138,7 +138,7 @@ 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");
}
@@ -181,7 +181,7 @@ 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");
}
@@ -239,7 +239,7 @@ 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");

@@ -285,7 +285,7 @@ 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/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h
index cb493bcae8b4..3551dd607b90 100644
--- a/drivers/pci/dwc/pcie-designware.h
+++ b/drivers/pci/dwc/pcie-designware.h
@@ -28,8 +28,7 @@

/* 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
--
2.17.1