| Message ID | 1464472878-27176-6-git-send-email-okaya@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Sinan, Le 29/05/2016 à 00:01, Sinan Kaya a écrit : > The device tree code checks for the presence of a reset driver and calls > the of_reset function pointer by looking up the reset driver as a module. > > ACPI defines _RST method to perform device level reset. After the _RST > method is executed, the OS can resume using the device. _RST method is > expected to stop DMA transfers and IRQs. > > This patch checks the presence of _RST method and calls the _RST > method when reset is requested. > > Signed-off-by: Sinan Kaya <okaya@codeaurora.org> > Reviewed-by: Eric Auger <eric.auger@linaro.org> code has changed compared to previous version and the R-b. In the future, please add change logs. Besides it looks ok to me. Best Regards Eric > --- > drivers/vfio/platform/vfio_platform_common.c | 51 ++++++++++++++++++++++++++++ > 1 file changed, 51 insertions(+) > > diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c > index e7ce2c2..0ea8c26 100644 > --- a/drivers/vfio/platform/vfio_platform_common.c > +++ b/drivers/vfio/platform/vfio_platform_common.c > @@ -73,21 +73,66 @@ static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev, > } > return 0; > } > + > +static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev, > + const char **extra_dbg) > +{ > + struct device *dev = vdev->device; > + acpi_handle handle = ACPI_HANDLE(dev); > + acpi_status acpi_ret; > + unsigned long long val; > + > + acpi_ret = acpi_evaluate_integer(handle, "_RST", NULL, &val); > + if (ACPI_FAILURE(acpi_ret)) { > + if (extra_dbg) > + *extra_dbg = acpi_format_exception(acpi_ret); > + return -EINVAL; > + } > + > + return 0; > +} > + > +static bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev) > +{ > + struct device *dev = vdev->device; > + acpi_handle handle = ACPI_HANDLE(dev); > + > + return acpi_has_method(handle, "_RST"); > +} > #else > static inline int vfio_platform_acpi_probe(struct vfio_platform_device *vdev, > struct device *dev) > { > return -ENOENT; > } > + > +static inline > +int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev, > + const char **extra_dbg) > +{ > + return -ENOENT; > +} > + > +static inline > +bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev) > +{ > + return false; > +} > #endif > > static bool vfio_platform_has_reset(struct vfio_platform_device *vdev) > { > + if (vdev->acpihid) > + return vfio_platform_acpi_has_reset(vdev); > + > return vdev->of_reset ? true : false; > } > > static void vfio_platform_get_reset(struct vfio_platform_device *vdev) > { > + if (vdev->acpihid) > + return; > + > vdev->of_reset = vfio_platform_lookup_reset(vdev->compat, > &vdev->reset_module); > if (!vdev->of_reset) { > @@ -99,6 +144,9 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev) > > static void vfio_platform_put_reset(struct vfio_platform_device *vdev) > { > + if (vdev->acpihid) > + return; > + > if (vdev->of_reset) > module_put(vdev->reset_module); > } > @@ -177,6 +225,9 @@ static int vfio_platform_call_reset(struct vfio_platform_device *vdev, > if (vdev->of_reset) { > dev_info(vdev->device, "reset\n"); > return vdev->of_reset(vdev); > + } else if (vdev->acpihid) { > + dev_info(vdev->device, "reset\n"); > + return vfio_platform_acpi_call_reset(vdev, extra_dbg); > } > > dev_warn(vdev->device, "no reset function found!\n"); >
On Sun, May 29, 2016 at 12:01 AM, Sinan Kaya <okaya@codeaurora.org> wrote: > The device tree code checks for the presence of a reset driver and calls > the of_reset function pointer by looking up the reset driver as a module. > > ACPI defines _RST method to perform device level reset. After the _RST > method is executed, the OS can resume using the device. _RST method is > expected to stop DMA transfers and IRQs. > > This patch checks the presence of _RST method and calls the _RST > method when reset is requested. You could check if _RST is present at probe time and store the ACPI handle of it instead of the HID pointer. This way you wouldn't need to repeat that check every time reset is used.
On 6/8/2016 6:31 PM, Rafael J. Wysocki wrote: > On Sun, May 29, 2016 at 12:01 AM, Sinan Kaya <okaya@codeaurora.org> wrote: >> The device tree code checks for the presence of a reset driver and calls >> the of_reset function pointer by looking up the reset driver as a module. >> >> ACPI defines _RST method to perform device level reset. After the _RST >> method is executed, the OS can resume using the device. _RST method is >> expected to stop DMA transfers and IRQs. >> >> This patch checks the presence of _RST method and calls the _RST >> method when reset is requested. > > You could check if _RST is present at probe time and store the ACPI > handle of it instead of the HID pointer. > > This way you wouldn't need to repeat that check every time reset is used. > Makes sense. I'll give it a shot.
On 6/8/2016 6:31 PM, Rafael J. Wysocki wrote: > On Sun, May 29, 2016 at 12:01 AM, Sinan Kaya <okaya@codeaurora.org> wrote: >> The device tree code checks for the presence of a reset driver and calls >> the of_reset function pointer by looking up the reset driver as a module. >> >> ACPI defines _RST method to perform device level reset. After the _RST >> method is executed, the OS can resume using the device. _RST method is >> expected to stop DMA transfers and IRQs. >> >> This patch checks the presence of _RST method and calls the _RST >> method when reset is requested. > A little bit of misinformation here. The current code is checking the presence during probe time. If the presence of _RST method is required then probe is aborted. Otherwise, probe will complete execution. When reset call is to be executed, presence of _RST method is no longer checked. Instead, the method is directly called. I was talking about the contribution of this patch as both here. I'll clarify the commit message. > You could check if _RST is present at probe time and store the ACPI > handle of it instead of the HID pointer. > > This way you wouldn't need to repeat that check every time reset is used. > Based on the requirement that the code can be executed without the presence of _RST method for development purposes, I'm hesitant to use the handle of the reset method as a gating factor.
diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c index e7ce2c2..0ea8c26 100644 --- a/drivers/vfio/platform/vfio_platform_common.c +++ b/drivers/vfio/platform/vfio_platform_common.c @@ -73,21 +73,66 @@ static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev, } return 0; } + +static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev, + const char **extra_dbg) +{ + struct device *dev = vdev->device; + acpi_handle handle = ACPI_HANDLE(dev); + acpi_status acpi_ret; + unsigned long long val; + + acpi_ret = acpi_evaluate_integer(handle, "_RST", NULL, &val); + if (ACPI_FAILURE(acpi_ret)) { + if (extra_dbg) + *extra_dbg = acpi_format_exception(acpi_ret); + return -EINVAL; + } + + return 0; +} + +static bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev) +{ + struct device *dev = vdev->device; + acpi_handle handle = ACPI_HANDLE(dev); + + return acpi_has_method(handle, "_RST"); +} #else static inline int vfio_platform_acpi_probe(struct vfio_platform_device *vdev, struct device *dev) { return -ENOENT; } + +static inline +int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev, + const char **extra_dbg) +{ + return -ENOENT; +} + +static inline +bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev) +{ + return false; +} #endif static bool vfio_platform_has_reset(struct vfio_platform_device *vdev) { + if (vdev->acpihid) + return vfio_platform_acpi_has_reset(vdev); + return vdev->of_reset ? true : false; } static void vfio_platform_get_reset(struct vfio_platform_device *vdev) { + if (vdev->acpihid) + return; + vdev->of_reset = vfio_platform_lookup_reset(vdev->compat, &vdev->reset_module); if (!vdev->of_reset) { @@ -99,6 +144,9 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev) static void vfio_platform_put_reset(struct vfio_platform_device *vdev) { + if (vdev->acpihid) + return; + if (vdev->of_reset) module_put(vdev->reset_module); } @@ -177,6 +225,9 @@ static int vfio_platform_call_reset(struct vfio_platform_device *vdev, if (vdev->of_reset) { dev_info(vdev->device, "reset\n"); return vdev->of_reset(vdev); + } else if (vdev->acpihid) { + dev_info(vdev->device, "reset\n"); + return vfio_platform_acpi_call_reset(vdev, extra_dbg); } dev_warn(vdev->device, "no reset function found!\n");