Michael Kelley (LINUX)
2023-Feb-01 18:32 UTC
[PATCH v2 3/6] Drivers: hv: vmbus: Convert acpi_device to platform_device
From: Saurabh Sengar <ssengar at linux.microsoft.com> Sent: Tuesday, January 31, 2023 10:10 AM> > Use more generic platform device instead of acpi device. Also rename the > function vmbus_acpi_remove to more generic name vmbus_mmio_remove. > > Signed-off-by: Saurabh Sengar <ssengar at linux.microsoft.com> > --- > drivers/hv/vmbus_drv.c | 78 +++++++++++++++++++++++++----------------- > 1 file changed, 46 insertions(+), 32 deletions(-) > > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c > index d24dd65b33d4..49030e756b9f 100644 > --- a/drivers/hv/vmbus_drv.c > +++ b/drivers/hv/vmbus_drv.c > @@ -12,6 +12,7 @@ > #include <linux/init.h> > #include <linux/module.h> > #include <linux/device.h> > +#include <linux/platform_device.h> > #include <linux/interrupt.h> > #include <linux/sysctl.h> > #include <linux/slab.h> > @@ -44,7 +45,7 @@ struct vmbus_dynid { > struct hv_vmbus_device_id id; > }; > > -static struct acpi_device *hv_acpi_dev; > +static struct platform_device *hv_dev; > > static int hyperv_cpuhp_online; > > @@ -143,7 +144,7 @@ static DEFINE_MUTEX(hyperv_mmio_lock); > > static int vmbus_exists(void) > { > - if (hv_acpi_dev == NULL) > + if (hv_dev == NULL) > return -ENODEV; > > return 0; > @@ -932,7 +933,7 @@ static int vmbus_dma_configure(struct device *child_device) > * On x86/x64 coherence is assumed and these calls have no effect. > */ > hv_setup_dma_ops(child_device, > - device_get_dma_attr(&hv_acpi_dev->dev) == DEV_DMA_COHERENT); > + device_get_dma_attr(&hv_dev->dev) == DEV_DMA_COHERENT); > return 0; > } > > @@ -2090,7 +2091,7 @@ int vmbus_device_register(struct hv_device > *child_device_obj) > &child_device_obj->channel->offermsg.offer.if_instance); > > child_device_obj->device.bus = &hv_bus; > - child_device_obj->device.parent = &hv_acpi_dev->dev; > + child_device_obj->device.parent = &hv_dev->dev; > child_device_obj->device.release = vmbus_device_release; > > child_device_obj->device.dma_parms = &child_device_obj->dma_parms; > @@ -2262,7 +2263,7 @@ static acpi_status vmbus_walk_resources(struct > acpi_resource *res, void *ctx) > return AE_OK; > } > > -static void vmbus_acpi_remove(struct acpi_device *device) > +static void vmbus_mmio_remove(void) > { > struct resource *cur_res; > struct resource *next_res; > @@ -2441,13 +2442,15 @@ void vmbus_free_mmio(resource_size_t start, > resource_size_t size) > } > EXPORT_SYMBOL_GPL(vmbus_free_mmio); > > -static int vmbus_acpi_add(struct acpi_device *device) > +static int vmbus_acpi_add(struct platform_device *pdev) > { > acpi_status result; > int ret_val = -ENODEV; > - struct acpi_device *ancestor; > + struct platform_device *ancestor; > + struct acpi_device *adev = to_acpi_device(&pdev->dev);This doesn't work. The argument to vmbus_acpi_add() is a struct platform_device, which has a struct device embedded in it (not a pointer). to_acpi_device() takes a struct device as an argument, assuming that the struct device is embedded in a struct acpi_device, which is not the case here. The resulting local variable adev is actually pointing to some (perhaps negative) offset within the struct platform_device, and uses of adev are getting unknown random data from within (or before) the struct platform_device.> > - hv_acpi_dev = device; > + hv_dev = pdev; > + adev->fwnode.dev = &pdev->dev; > > /* > * Older versions of Hyper-V for ARM64 fail to include the _CCA > @@ -2456,15 +2459,16 @@ static int vmbus_acpi_add(struct acpi_device *device) > * up the ACPI device to behave as if _CCA is present and indicates > * hardware coherence. > */ > - ACPI_COMPANION_SET(&device->dev, device); > + ACPI_COMPANION_SET(&pdev->dev, ACPI_COMPANION(&pdev->dev));This statement seems tautological. If ACPI_COMPANION(&pdev->dev) returns a valid result, why would the ACPI companion for &pdev->dev need to be set? The original code was setting the ACPI companion for the embedded struct device to be the struct acpi_device. I forget why this wasn't already done for the VMBus device when it was originally parsed from the ACPI DSDT ...> if (IS_ENABLED(CONFIG_ACPI_CCA_REQUIRED) && > - device_get_dma_attr(&device->dev) == DEV_DMA_NOT_SUPPORTED) { > + device_get_dma_attr(&pdev->dev) == DEV_DMA_NOT_SUPPORTED) { > + struct acpi_device *adev_node = ACPI_COMPANION(&pdev->dev);If earlier code in this function can get a correct pointer to the struct acpi_device, then this statement shouldn't be necessary. You already have it.> pr_info("No ACPI _CCA found; assuming coherent device I/O\n"); > - device->flags.cca_seen = true; > - device->flags.coherent_dma = true; > + adev_node->flags.cca_seen = true; > + adev_node->flags.coherent_dma = true; > } > > - result = acpi_walk_resources(device->handle, METHOD_NAME__CRS, > + result = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), METHOD_NAME__CRS,Again, if you have a correct pointer to the struct acpi_device, then adev->handle (like the original code) should be simpler than looking it up again with ACPI_HANDLE().> vmbus_walk_resources, NULL); > > if (ACPI_FAILURE(result)) > @@ -2473,9 +2477,9 @@ static int vmbus_acpi_add(struct acpi_device *device) > * Some ancestor of the vmbus acpi device (Gen1 or Gen2 > * firmware) is the VMOD that has the mmio ranges. Get that. > */ > - for (ancestor = acpi_dev_parent(device); ancestor; > - ancestor = acpi_dev_parent(ancestor)) { > - result = acpi_walk_resources(ancestor->handle, METHOD_NAME__CRS, > + for (ancestor = to_platform_device(pdev->dev.parent); ancestor; > + ancestor = to_platform_device(ancestor->dev.parent)) { > + result = acpi_walk_resources(ACPI_HANDLE(&ancestor->dev), METHOD_NAME__CRS,Similarly, if you get a correct pointer to the struct acpi_device, does the above code need any changes? I'm hoping not.> vmbus_walk_resources, NULL); > > if (ACPI_FAILURE(result)) > @@ -2489,10 +2493,21 @@ static int vmbus_acpi_add(struct acpi_device *device) > > acpi_walk_err: > if (ret_val) > - vmbus_acpi_remove(device); > + vmbus_mmio_remove(); > return ret_val; > } > > +static int vmbus_platform_driver_probe(struct platform_device *pdev) > +{ > + return vmbus_acpi_add(pdev); > +} > + > +static int vmbus_platform_driver_remove(struct platform_device *pdev) > +{ > + vmbus_mmio_remove(); > + return 0; > +} > + > #ifdef CONFIG_PM_SLEEP > static int vmbus_bus_suspend(struct device *dev) > { > @@ -2658,15 +2673,15 @@ static const struct dev_pm_ops vmbus_bus_pm = { > .restore_noirq = vmbus_bus_resume > }; > > -static struct acpi_driver vmbus_acpi_driver = { > - .name = "vmbus", > - .ids = vmbus_acpi_device_ids, > - .ops = { > - .add = vmbus_acpi_add, > - .remove = vmbus_acpi_remove, > - }, > - .drv.pm = &vmbus_bus_pm, > - .drv.probe_type = PROBE_FORCE_SYNCHRONOUS, > +static struct platform_driver vmbus_platform_driver = { > + .probe = vmbus_platform_driver_probe, > + .remove = vmbus_platform_driver_remove, > + .driver = { > + .name = "vmbus", > + .acpi_match_table = ACPI_PTR(vmbus_acpi_device_ids), > + .pm = &vmbus_bus_pm, > + .probe_type = PROBE_FORCE_SYNCHRONOUS, > + } > }; > > static void hv_kexec_handler(void) > @@ -2750,12 +2765,11 @@ static int __init hv_acpi_init(void) > /* > * Get ACPI resources first. > */ > - ret = acpi_bus_register_driver(&vmbus_acpi_driver); > - > + ret = platform_driver_register(&vmbus_platform_driver); > if (ret) > return ret; > > - if (!hv_acpi_dev) { > + if (!hv_dev) { > ret = -ENODEV; > goto cleanup; > } > @@ -2785,8 +2799,8 @@ static int __init hv_acpi_init(void) > return 0; > > cleanup: > - acpi_bus_unregister_driver(&vmbus_acpi_driver); > - hv_acpi_dev = NULL; > + platform_driver_unregister(&vmbus_platform_driver); > + hv_dev = NULL; > return ret; > } > > @@ -2839,7 +2853,7 @@ static void __exit vmbus_exit(void) > > cpuhp_remove_state(hyperv_cpuhp_online); > hv_synic_free(); > - acpi_bus_unregister_driver(&vmbus_acpi_driver); > + platform_driver_unregister(&vmbus_platform_driver); > } > > > -- > 2.25.1