@@ -54,6 +54,9 @@ config ACPI_GENERIC_GSI
config ACPI_SYSTEM_POWER_STATES_SUPPORT
bool
+config ACPI_CCA_REQUIRED
+ bool
+
config ACPI_SLEEP
bool
depends on SUSPEND || HIBERNATION
@@ -103,7 +103,7 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *adev)
pdevinfo.res = resources;
pdevinfo.num_res = count;
pdevinfo.fwnode = acpi_fwnode_handle(adev);
- pdevinfo.dma_mask = DMA_BIT_MASK(32);
+ pdevinfo.dma_mask = acpi_check_dma(adev, NULL) ? DMA_BIT_MASK(32) : 0;
pdev = platform_device_register_full(&pdevinfo);
if (IS_ERR(pdev))
dev_err(&adev->dev, "platform device creation failed: %ld\n",
@@ -13,6 +13,7 @@
#include <linux/slab.h>
#include <linux/rwsem.h>
#include <linux/acpi.h>
+#include <linux/dma-mapping.h>
#include "internal.h"
@@ -167,6 +168,7 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev)
struct list_head *physnode_list;
unsigned int node_id;
int retval = -EINVAL;
+ bool coherent;
if (has_acpi_companion(dev)) {
if (acpi_dev) {
@@ -223,6 +225,9 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev)
if (!has_acpi_companion(dev))
ACPI_COMPANION_SET(dev, acpi_dev);
+ if (acpi_check_dma(acpi_dev, &coherent))
+ arch_setup_dma_ops(dev, 0, 0, NULL, coherent);
+
acpi_physnode_link_name(physical_node_name, node_id);
retval = sysfs_create_link(&acpi_dev->dev.kobj, &dev->kobj,
physical_node_name);
@@ -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>
@@ -2137,6 +2138,39 @@ void acpi_free_pnp_ids(struct acpi_device_pnp *pnp)
kfree(pnp->unique_id);
}
+static void acpi_init_coherency(struct acpi_device *adev)
+{
+ unsigned long long cca = 0;
+ acpi_status status;
+ struct acpi_device *parent = adev->parent;
+
+ if (parent && parent->flags.cca_seen) {
+ /*
+ * From ACPI spec, OSPM will ignore _CCA if an ancestor
+ * already saw one.
+ */
+ adev->flags.cca_seen = 1;
+ cca = parent->flags.coherent_dma;
+ } else {
+ status = acpi_evaluate_integer(adev->handle, "_CCA",
+ NULL, &cca);
+ if (ACPI_SUCCESS(status))
+ adev->flags.cca_seen = 1;
+ else if (!IS_ENABLED(CONFIG_ACPI_CCA_REQUIRED))
+ /*
+ * If architecture does not specify that _CCA is
+ * required for DMA-able devices (e.g. x86),
+ * we default to _CCA=1.
+ */
+ cca = 1;
+ else
+ acpi_handle_debug(adev->handle,
+ "ACPI device is missing _CCA.\n");
+ }
+
+ adev->flags.coherent_dma = cca;
+}
+
void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
int type, unsigned long long sta)
{
@@ -2155,6 +2189,7 @@ void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
device->flags.visited = false;
device_initialize(&device->dev);
dev_set_uevent_suppress(&device->dev, true);
+ acpi_init_coherency(device);
}
void acpi_device_add_finalize(struct acpi_device *device)
@@ -208,7 +208,9 @@ struct acpi_device_flags {
u32 visited:1;
u32 hotplug_notify:1;
u32 is_dock_station:1;
- u32 reserved:23;
+ u32 coherent_dma:1;
+ u32 cca_seen:1;
+ u32 reserved:21;
};
/* File System */
@@ -380,6 +382,39 @@ struct acpi_device {
void (*remove)(struct acpi_device *);
};
+static inline bool acpi_check_dma(struct acpi_device *adev, bool *coherent)
+{
+ bool ret = false;
+
+ if (!adev)
+ return ret;
+
+ /**
+ * Currently, we only support _CCA=1 (i.e. coherent_dma=1)
+ * This should be equivalent to specifyig dma-coherent for
+ * a device in OF.
+ *
+ * For the case when _CCA=0 (i.e. coherent_dma=0 && cca_seen=1),
+ * There are two cases:
+ * case 1. Do not support and disable DMA.
+ * case 2. Support but rely on arch-specific cache maintenance for
+ * non-coherence DMA operations.
+ * Currently, we implement case 1 above.
+ *
+ * For the case when _CCA is missing (i.e. cca_seen=0) and
+ * platform specifies ACPI_CCA_REQUIRED, we do not support DMA,
+ * and fallback to arch-specific default handling.
+ *
+ * See acpi_init_coherency() for more info.
+ */
+ if (adev->flags.coherent_dma) {
+ ret = true;
+ if (coherent)
+ *coherent = adev->flags.coherent_dma;
+ }
+ return ret;
+}
+
static inline bool is_acpi_node(struct fwnode_handle *fwnode)
{
return fwnode && fwnode->type == FWNODE_ACPI;
@@ -583,6 +583,11 @@ static inline int acpi_device_modalias(struct device *dev,
return -ENODEV;
}
+static inline bool acpi_check_dma(struct acpi_device *adev, bool *coherent)
+{
+ return false;
+}
+
#define ACPI_PTR(_ptr) (NULL)
#endif /* !CONFIG_ACPI */