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. 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"); -- 2.1.0 -- 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/
