On Wed, 2015-04-01 at 10:20 -0500, Suravee Suthikulpanit wrote: > ACPI v5.1 introduced _CCA object for specifying cache coherency attribute > for devices. This patch implements a logic, which traverses device namespace > to parse the coherency information, and calling the corresponded > arch_setup_dma_ops(). > > It checks the _CCA during ACPI scan, and setup coherency during acpi_device > creation. > Then, this is propagted to the platform_device when it is created at later > time. > > CC: Mark Salter <msal...@redhat.com> > CC: Hanjun Guo <hanjun....@linaro.org> > CC: Al Stone <al.st...@linaro.org> > Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com> > --- > > NOTE: > > The original patch has been submitted by Mark Salter, and discussed here: > > * http://comments.gmane.org/gmane.linux.acpi.devel/70424 > > One of the reveiw comment was dissusing whether we need the do/while loop for > travesing parents of the device. AFAIK, there are no APIs that would do > upsearch > from a particular node. The acpi_get_handle() is the closest one, but it is > using > ACPI_NS_NO_UPSEARCH.
I'm interested in this question also. I looked at the ns walking interfaces but couldn't find a good way to do what was needed. Would it be better to add _CCA info to acpi_device and then look for it during enumeration? That way an acpi_device would always have the info either from _CCA or inherited from its parent. > > This has been rebased and tested with: > * http://git.linaro.org/leg/acpi/acpi.git acpi-5.1-v11 > * [V8 PATCH 0/3] Introduce ACPI support for ahci_platform driver > (https://lkml.org/lkml/2015/3/30/729) > > drivers/acpi/acpi_platform.c | 5 +++- > drivers/acpi/scan.c | 56 > ++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 60 insertions(+), 1 deletion(-) > > diff --git a/drivers/acpi/acpi_platform.c b/drivers/acpi/acpi_platform.c > index 1284138..47e37a8 100644 > --- a/drivers/acpi/acpi_platform.c > +++ b/drivers/acpi/acpi_platform.c > @@ -108,9 +108,12 @@ struct platform_device > *acpi_create_platform_device(struct acpi_device *adev) > if (IS_ERR(pdev)) > dev_err(&adev->dev, "platform device creation failed: %ld\n", > PTR_ERR(pdev)); > - else > + else { > + arch_setup_dma_ops(&pdev->dev, 0, 0, NULL, > + is_device_dma_coherent(&adev->dev)); > dev_dbg(&adev->dev, "created platform device %s\n", > dev_name(&pdev->dev)); > + } > > kfree(resources); > return pdev; > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > index 230ec983..4d81c55 100644 > --- a/drivers/acpi/scan.c > +++ b/drivers/acpi/scan.c > @@ -11,6 +11,7 @@ > #include <linux/kthread.h> > #include <linux/dmi.h> > #include <linux/nls.h> > +#include <linux/dma-mapping.h> > > #include <asm/pgtable.h> > > @@ -57,6 +58,9 @@ struct acpi_device_bus_id{ > struct list_head node; > }; > > +static int acpi_bus_type_and_status(acpi_handle handle, int *type, > + unsigned long long *sta); > + > void acpi_scan_lock_acquire(void) > { > mutex_lock(&acpi_scan_lock); > @@ -1327,6 +1331,51 @@ void acpi_bus_put_acpi_device(struct acpi_device *adev) > put_device(&adev->dev); > } > > +/** > + * acpi_check_and_set_coherency - check and set cache coherency of a device > + * @device: ACPI device > + * > + * Search a device and its parents for a _CCA method and calculate > + * the effective coherency property of the device. If found, set up > + * appropriate dma_ops for the device. > + * > + * Note From ACPIv5.1 spec: > + * If used _CCA must be included under all bus-master-capable > + * devices defined as children of \_SB. The value of _CCA is inherited > + * by all descendants of these devices, so it need not be repeated for > + * their children devices and will be ignored by OSPM if it is provided > + * there. > + */ > +static int acpi_check_and_set_coherency(struct acpi_device *device) > +{ > + acpi_status status; > + unsigned long long eff_cca = ~0ULL; > + acpi_handle tmp, handle = device->handle; > + > + /* Calculate effective _CCA from all parents of this device */ > + do { > + unsigned long cca; > + > + status = acpi_get_handle(handle, "_CCA", &tmp); > + if (ACPI_SUCCESS(status)) { > + status = acpi_evaluate_integer(tmp, "_CCA", NULL, &cca); > + /* Other values besides 0 and 1 are reserved */ > + if (ACPI_FAILURE(status) || (cca != 0 && cca != 1)) > + return -EINVAL; > + eff_cca = cca; > + } > + > + status = acpi_get_parent(handle, &handle); > + if (ACPI_FAILURE(status)) > + break; > + } while (ACPI_SUCCESS(status)); > + > + if (eff_cca != ~0ULL) > + arch_setup_dma_ops(&device->dev, 0, 0, NULL, eff_cca); > + > + return 0; > +} > + > int acpi_device_add(struct acpi_device *device, > void (*release)(struct device *)) > { > @@ -1398,6 +1447,13 @@ int acpi_device_add(struct acpi_device *device, > device->dev.parent = &device->parent->dev; > device->dev.bus = &acpi_bus_type; > device->dev.release = release; > + > + result = acpi_check_and_set_coherency(device); > + if (result) { > + dev_err(&device->dev, "Error getting device _CCA > information\n"); > + goto err; > + } > + > result = device_add(&device->dev); > if (result) { > dev_err(&device->dev, "Error registering device\n"); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
