On Wednesday, April 01, 2015 10:20:20 AM 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 msalter@redhat.com CC: Hanjun Guo hanjun.guo@linaro.org CC: Al Stone al.stone@linaro.org Signed-off-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com
NOTE:
The original patch has been submitted by Mark Salter, and discussed here:
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));- }
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);
So if I'm not mistaken, this is going to evaluate _CCA for all of the ancestors of the device even though it already might have been evaluated for all of them.
Any chance to optimize it somewhat?
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");