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* [PATCH v3] PCI: dwc: fix scheduling while atomic issues
@ 2018-08-29  3:04 ` Jisheng Zhang
  0 siblings, 0 replies; 19+ messages in thread
From: Jisheng Zhang @ 2018-08-29  3:04 UTC (permalink / raw)
  To: Jingoo Han, Joao Pinto, Bjorn Helgaas, Lorenzo Pieralisi,
	linux-pci, linux-kernel, linux-arm-kernel

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 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>
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
---

since v2:
 - Add Fixes tag
 - Add Gustavo's Ack

since v1:
 - use mdelay() instead of udelay() to avoid __bad_udelay()

 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..2153956a0b20 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);
+		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
index 96126fd8403c..9f1a5e399b70 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			9
 
 /* Synopsys-specific PCIe configuration registers */
 #define PCIE_PORT_LINK_CONTROL		0x710
-- 
2.18.0


^ permalink raw reply related	[flat|nested] 19+ messages in thread

end of thread, other threads:[~2018-09-20 21:37 UTC | newest]

Thread overview: 19+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-08-29  3:04 [PATCH v3] PCI: dwc: fix scheduling while atomic issues Jisheng Zhang
2018-08-29  3:04 ` Jisheng Zhang
2018-08-29  3:04 ` Jisheng Zhang
2018-09-10  8:57 ` Jisheng Zhang
2018-09-10  8:57   ` Jisheng Zhang
2018-09-10  8:57   ` Jisheng Zhang
2018-09-13  9:15   ` Lorenzo Pieralisi
2018-09-13  9:15     ` Lorenzo Pieralisi
2018-09-13 10:29     ` Jisheng Zhang
2018-09-13 10:29       ` Jisheng Zhang
2018-09-13 10:29       ` Jisheng Zhang
2018-09-13 10:49       ` Lorenzo Pieralisi
2018-09-13 10:49         ` Lorenzo Pieralisi
2018-09-13 10:49         ` Lorenzo Pieralisi
2018-09-13 15:05 ` Lorenzo Pieralisi
2018-09-13 15:05   ` Lorenzo Pieralisi
2018-09-13 15:05   ` Lorenzo Pieralisi
2018-09-20 21:37   ` Bjorn Helgaas
2018-09-20 21:37     ` Bjorn Helgaas

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