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PCI: dwc: fix scheduling while atomic issues

PATCH Superseded Jisheng Zhang 3 participants 3 messages Aug 21, 2018 – Aug 28, 2018

Subsystems (3)
PCI PCI native host bridge and endpoint drivers PCI driver for synopsys DesignWare

v2 of 3 Superseded Latest is v3 →

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Jisheng Zhang

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#0 lore raw

PATCH v2 1/1 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 mdelay() instead.

Signed-off-by Jisheng Zhang <[email protected]>

---

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(-)
drivers/pci/controller/dwc/pcie-designware.c +4 -4
index 778c4f76a884..2153956a0b20 100644
@@ -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");
drivers/pci/controller/dwc/pcie-designware.h +1 -2
index 96126fd8403c..9f1a5e399b70 100644
@@ -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
Signature · 1 line
2.18.0
Acked-by on v2 1/1
#1 lore raw

Hi Jisheng

Quoted 7 lines · Jisheng Zhang

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()

Quoted 8 lines
    =>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.

Makes sense. Thanks.

Acked-by Gustavo Pimentel <[email protected]>

Regards,
Gustavo

Quoted 66 lines
Signed-off-by Jisheng Zhang <[email protected]>

---

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(-)
drivers/pci/controller/dwc/pcie-designware.c +4 -4
index 778c4f76a884..2153956a0b20 100644
@@ -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");
drivers/pci/controller/dwc/pcie-designware.h +1 -2
index 96126fd8403c..9f1a5e399b70 100644
@@ -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 lore raw
In reply to Jisheng Zhang
Quoted 9 lines · Jisheng Zhang

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()
Quoted 8 lines

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.

Signed-off-by Jisheng Zhang <[email protected]>

Mind adding a Fixes: tag please ?

Is:

commit f8aed6ec624f ("PCI: dwc: designware: Add EP mode support")

the commit you are fixing ?

Thanks,
Lorenzo

Quoted 66 lines

---

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(-)
drivers/pci/controller/dwc/pcie-designware.c +4 -4
index 778c4f76a884..2153956a0b20 100644
@@ -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");
drivers/pci/controller/dwc/pcie-designware.h +1 -2
index 96126fd8403c..9f1a5e399b70 100644
@@ -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
Signature · 1 line
2.18.0