2018-08-21 06:22:22

by Jisheng Zhang

Subject: [PATCH v2] 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(-)

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

2018-08-22 09:51:06

by Gustavo Pimentel

Subject: Re: [PATCH v2] PCI: dwc: fix scheduling while atomic issues

Hi Jisheng

On 21/08/2018 07:15, Jisheng Zhang wrote:
> 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.

Makes sense. Thanks.

Acked-by: Gustavo Pimentel <[email protected]>

Regards,
Gustavo

>
> 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(-)
>
> 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
>

2018-08-28 10:11:35

by Lorenzo Pieralisi

Subject: Re: [PATCH v2] PCI: dwc: fix scheduling while atomic issues

On Tue, Aug 21, 2018 at 02:15:12PM +0800, Jisheng Zhang wrote:
> 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]>

Mind adding a Fixes: tag please ?

Is:

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

the commit you are fixing ?

Thanks,
Lorenzo

> ---
>
> 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
>