From mboxrd@z Thu Jan 1 00:00:00 1970 From: okaya@codeaurora.org (Sinan Kaya) Date: Wed, 13 Jul 2016 22:06:30 -0400 Subject: [PATCH V9 4/9] vfio: platform: add support for ACPI probe In-Reply-To: <1468461995-32676-1-git-send-email-okaya@codeaurora.org> References: <1468461995-32676-1-git-send-email-okaya@codeaurora.org> Message-ID: <1468461995-32676-5-git-send-email-okaya@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org The code is using the compatible DT string to associate a reset driver with the actual device itself. The compatible string does not exist on ACPI based systems. HID is the unique identifier for a device driver instead. Signed-off-by: Sinan Kaya Reviewed-by: Eric Auger Reviewed-by: Baptiste Reynal --- drivers/vfio/platform/vfio_platform_common.c | 70 +++++++++++++++++++++++++-- drivers/vfio/platform/vfio_platform_private.h | 1 + 2 files changed, 66 insertions(+), 5 deletions(-) diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c index 6be92c3..ff148764 100644 --- a/drivers/vfio/platform/vfio_platform_common.c +++ b/drivers/vfio/platform/vfio_platform_common.c @@ -13,6 +13,7 @@ */ #include +#include #include #include #include @@ -49,6 +50,33 @@ static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat, return reset_fn; } +static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev, + struct device *dev) +{ + struct acpi_device *adev = ACPI_COMPANION(dev); + + if (acpi_disabled) + return -EPERM; + + if (!adev) { + pr_err("VFIO: ACPI companion device not found for %s\n", + vdev->name); + return -ENODEV; + } + +#ifdef CONFIG_ACPI + vdev->acpihid = acpi_device_hid(adev); + if (!vdev->acpihid) { + pr_err("VFIO: cannot find ACPI HID for %s\n", + vdev->name); + return -EINVAL; + } + return 0; +#else + return -ENOENT; +#endif +} + static bool vfio_platform_has_reset(struct vfio_platform_device *vdev) { return vdev->of_reset ? true : false; @@ -547,6 +575,37 @@ static const struct vfio_device_ops vfio_platform_ops = { .mmap = vfio_platform_mmap, }; +int vfio_platform_of_probe(struct vfio_platform_device *vdev, + struct device *dev) +{ + int ret; + + ret = device_property_read_string(dev, "compatible", + &vdev->compat); + if (ret) + pr_err("VFIO: cannot retrieve compat for %s\n", + vdev->name); + + return ret; +} + +/* + * There can be two kernel build combinations. One build where + * ACPI is not selected in Kconfig and another one with the ACPI Kconfig. + * + * In the first case, vfio_platform_acpi_probe will return since + * acpi_disabled * is 1. DT user will not see any kind of messages from + * ACPI. + * + * In the second case, both DT and ACPI is compiled in but the system is + * booting with any of these combinations. + * + * If the firmware is DT type, then acpi_disabled is 1. The ACPI probe routine + * terminates immediately without any messages. + * + * If the firmware is ACPI type, then acpi_disabled is 0. All other checks are + * valid checks. We cannot claim that this system is DT. + */ int vfio_platform_probe_common(struct vfio_platform_device *vdev, struct device *dev) { @@ -556,11 +615,12 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev, if (!vdev) return -EINVAL; - ret = device_property_read_string(dev, "compatible", &vdev->compat); - if (ret) { - pr_err("VFIO: cannot retrieve compat for %s\n", vdev->name); - return -EINVAL; - } + ret = vfio_platform_acpi_probe(vdev, dev); + if (ret) + ret = vfio_platform_of_probe(vdev, dev); + + if (ret) + return ret; vdev->device = dev; diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h index 71ed7d1..ba9e4f8 100644 --- a/drivers/vfio/platform/vfio_platform_private.h +++ b/drivers/vfio/platform/vfio_platform_private.h @@ -58,6 +58,7 @@ struct vfio_platform_device { struct mutex igate; struct module *parent_module; const char *compat; + const char *acpihid; struct module *reset_module; struct device *device; -- 1.8.2.1