From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751915AbcFWS7v (ORCPT ); Thu, 23 Jun 2016 14:59:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52484 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751355AbcFWS7u (ORCPT ); Thu, 23 Jun 2016 14:59:50 -0400 Date: Thu, 23 Jun 2016 12:59:48 -0600 From: Alex Williamson To: Sinan Kaya Cc: kvm@vger.kernel.org, timur@codeaurora.org, cov@codeaurora.org, jcm@redhat.com, eric.auger@linaro.org, linux-acpi@vger.kernel.org, agross@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Baptiste Reynal , linux-kernel@vger.kernel.org Subject: Re: [PATCH V7 6/9] vfio: platform: call _RST method when using ACPI Message-ID: <20160623125948.59a8c656@t450s.home> In-Reply-To: <1465792001-27960-7-git-send-email-okaya@codeaurora.org> References: <1465792001-27960-1-git-send-email-okaya@codeaurora.org> <1465792001-27960-7-git-send-email-okaya@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Thu, 23 Jun 2016 18:59:49 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 13 Jun 2016 00:26:38 -0400 Sinan Kaya 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 introduces two functions as vfio_platform_acpi_has_reset and > vfio_platform_acpi_call_reset. The has reset method is used to declare > reset capability via the ioctl flag VFIO_DEVICE_FLAGS_RESET. The call > reset function is used to execute the _RST ACPI method. > > Signed-off-by: Sinan Kaya > Reviewed-by: Eric Auger > --- > 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); nit, all the cases until this one prioritize ACPI over DT, here we have the opposite. Granted we should never have of_reset set when acpihid is set. A macro like #define vfio_platform_is_acpi(vdev) (vdev->acpihid != NULL) might be useful. > } > > dev_warn(vdev->device, "no reset function found!\n");