[PATCH 10/33] powerpc/pseries: use the generic iommu bypass code

Christoph Hellwig
2018-10-09T13:25:50Z

Use the generic iommu bypass code instead of overriding set_dma_mask.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/powerpc/platforms/pseries/iommu.c | 100 +++++++------------------
1 file changed, 27 insertions(+), 73 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index da5716de7f4c..8965d174c53b 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -973,7 +973,7 @@ static LIST_HEAD(failed_ddw_pdn_list);
* pdn: the parent pe node with the ibm,dma_window property
* Future: also check if we can remap the base window for our base page size
*
- * returns the dma offset for use by dma_set_mask
+ * returns the dma offset for use by the direct mapped DMA code.
*/
static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
{
@@ -1193,87 +1193,40 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
iommu_add_device(&dev->dev);
}

-static int dma_set_mask_pSeriesLP(struct device *dev, u64 dma_mask)
+static bool iommu_bypass_supported_pSeriesLP(struct pci_dev *pdev, u64 dma_mask)
{
- bool ddw_enabled = false;
- struct device_node *pdn, *dn;
- struct pci_dev *pdev;
+ struct device_node *dn = pci_device_to_OF_node(pdev), *pdn;
const __be32 *dma_window = NULL;
u64 dma_offset;

- if (!dev->dma_mask)
- return -EIO;
-
- if (!dev_is_pci(dev))
- goto check_mask;
-
- pdev = to_pci_dev(dev);
-
/* only attempt to use a new window if 64-bit DMA is requested */
- if (!disable_ddw && dma_mask == DMA_BIT_MASK(64)) {
- dn = pci_device_to_OF_node(pdev);
- dev_dbg(dev, "node is %pOF\n", dn);
+ if (dma_mask < DMA_BIT_MASK(64))
+ return false;

- /*
- * the device tree might contain the dma-window properties
- * per-device and not necessarily for the bus. So we need to
- * search upwards in the tree until we either hit a dma-window
- * property, OR find a parent with a table already allocated.
- */
- for (pdn = dn; pdn && PCI_DN(pdn) && !PCI_DN(pdn)->table_group;
- pdn = pdn->parent) {
- dma_window = of_get_property(pdn, "ibm,dma-window", NULL);
- if (dma_window)
- break;
- }
- if (pdn && PCI_DN(pdn)) {
- dma_offset = enable_ddw(pdev, pdn);
- if (dma_offset != 0) {
- dev_info(dev, "Using 64-bit direct DMA at offset %llx\n", dma_offset);
- set_dma_offset(dev, dma_offset);
- set_dma_ops(dev, &dma_nommu_ops);
- ddw_enabled = true;
- }
- }
- }
+ dev_dbg(&pdev->dev, "node is %pOF\n", dn);

- /* fall back on iommu ops */
- if (!ddw_enabled && get_dma_ops(dev) != &dma_iommu_ops) {
- dev_info(dev, "Restoring 32-bit DMA via iommu\n");
- set_dma_ops(dev, &dma_iommu_ops);
+ /*
+ * the device tree might contain the dma-window properties
+ * per-device and not necessarily for the bus. So we need to
+ * search upwards in the tree until we either hit a dma-window
+ * property, OR find a parent with a table already allocated.
+ */
+ for (pdn = dn; pdn && PCI_DN(pdn) && !PCI_DN(pdn)->table_group;
+ pdn = pdn->parent) {
+ dma_window = of_get_property(pdn, "ibm,dma-window", NULL);
+ if (dma_window)
+ break;
}

-check_mask:
- if (!dma_supported(dev, dma_mask))
- return -EIO;
-
- *dev->dma_mask = dma_mask;
- return 0;
-}
-
-static u64 dma_get_required_mask_pSeriesLP(struct device *dev)
-{
- if (!dev->dma_mask)
- return 0;
-
- if (!disable_ddw && dev_is_pci(dev)) {
- struct pci_dev *pdev = to_pci_dev(dev);
- struct device_node *dn;
-
- dn = pci_device_to_OF_node(pdev);
-
- /* search upwards for ibm,dma-window */
- for (; dn && PCI_DN(dn) && !PCI_DN(dn)->table_group;
- dn = dn->parent)
- if (of_get_property(dn, "ibm,dma-window", NULL))
- break;
- /* if there is a ibm,ddw-applicable property require 64 bits */
- if (dn && PCI_DN(dn) &&
- of_get_property(dn, "ibm,ddw-applicable", NULL))
- return DMA_BIT_MASK(64);
+ if (pdn && PCI_DN(pdn)) {
+ dma_offset = enable_ddw(pdev, pdn);
+ if (dma_offset != 0) {
+ set_dma_offset(&pdev->dev, dma_offset);
+ return true;
+ }
}

- return dma_iommu_get_required_mask(dev);
+ return false;
}

static int iommu_mem_notifier(struct notifier_block *nb, unsigned long action,
@@ -1368,8 +1321,9 @@ void iommu_init_early_pSeries(void)
if (firmware_has_feature(FW_FEATURE_LPAR)) {
pseries_pci_controller_ops.dma_bus_setup = pci_dma_bus_setup_pSeriesLP;
pseries_pci_controller_ops.dma_dev_setup = pci_dma_dev_setup_pSeriesLP;
- ppc_md.dma_set_mask = dma_set_mask_pSeriesLP;
- ppc_md.dma_get_required_mask = dma_get_required_mask_pSeriesLP;
+ if (!disable_ddw)
+ pseries_pci_controller_ops.iommu_bypass_supported =
+ iommu_bypass_supported_pSeriesLP;
} else {
pseries_pci_controller_ops.dma_bus_setup = pci_dma_bus_setup_pSeries;
pseries_pci_controller_ops.dma_dev_setup = pci_dma_dev_setup_pSeries;
--
2.19.0