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Subject[PATCH] PCI: dwc: fix scheduling while atomic issues
When programming inbound/outbound atu, we call usleep_range() after
each checking PCIE_ATU_ENABLE bit. Unfortunately, the atu programming
can be called 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 udelay() instead.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
---
drivers/pci/controller/dwc/pcie-designware.c | 8 ++++----
drivers/pci/controller/dwc/pcie-designware.h | 3 +--
2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 778c4f76a884..4c15929d9c79 100644
--- 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);
+ udelay(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);
+ udelay(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);
+ udelay(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);
+ udelay(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
index 96126fd8403c..8bab329c5cd3 100644
--- 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 9000

/* Synopsys-specific PCIe configuration registers */
#define PCIE_PORT_LINK_CONTROL 0x710
--
2.18.0
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