powerpc: add real mode support for dma operations on powernv

The existing TCE machine calls (tce_build and tce_free) only support
virtual mode as they call __raw_writeq for TCE invalidation what
fails in real mode.

This introduces tce_build_rm and tce_free_rm real mode versions
which do mostly the same but use "Store Doubleword Caching Inhibited
Indexed" instruction for TCE invalidation.

This new feature is going to be utilized by real mode support of VFIO.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 37 insertions, 12 deletions

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 74a5a5773b1f..307015d9cd99 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -70,6 +70,16 @@ define_pe_printk_level(pe_err, KERN_ERR);
 define_pe_printk_level(pe_warn, KERN_WARNING);
 define_pe_printk_level(pe_info, KERN_INFO);
 
+/*
+ * stdcix is only supposed to be used in hypervisor real mode as per
+ * the architecture spec
+ */
+static inline void __raw_rm_writeq(u64 val, volatile void __iomem *paddr)
+{
+	__asm__ __volatile__("stdcix %0,0,%1"
+		: : "r" (val), "r" (paddr) : "memory");
+}
+
 static int pnv_ioda_alloc_pe(struct pnv_phb *phb)
 {
 	unsigned long pe;
@@ -454,10 +464,13 @@ static void pnv_ioda_setup_bus_dma(struct pnv_ioda_pe *pe, struct pci_bus *bus)
 	}
 }
 
-static void pnv_pci_ioda1_tce_invalidate(struct iommu_table *tbl,
-					 u64 *startp, u64 *endp)
+static void pnv_pci_ioda1_tce_invalidate(struct pnv_ioda_pe *pe,
+					 struct iommu_table *tbl,
+					 u64 *startp, u64 *endp, bool rm)
 {
-	u64 __iomem *invalidate = (u64 __iomem *)tbl->it_index;
+	u64 __iomem *invalidate = rm ?
+		(u64 __iomem *)pe->tce_inval_reg_phys :
+		(u64 __iomem *)tbl->it_index;
 	unsigned long start, end, inc;
 
 	start = __pa(startp);
@@ -484,7 +497,10 @@ static void pnv_pci_ioda1_tce_invalidate(struct iommu_table *tbl,
 
         mb(); /* Ensure above stores are visible */
         while (start <= end) {
-                __raw_writeq(start, invalidate);
+		if (rm)
+			__raw_rm_writeq(start, invalidate);
+		else
+			__raw_writeq(start, invalidate);
                 start += inc;
         }
 
@@ -496,10 +512,12 @@ static void pnv_pci_ioda1_tce_invalidate(struct iommu_table *tbl,
 
 static void pnv_pci_ioda2_tce_invalidate(struct pnv_ioda_pe *pe,
 					 struct iommu_table *tbl,
-					 u64 *startp, u64 *endp)
+					 u64 *startp, u64 *endp, bool rm)
 {
 	unsigned long start, end, inc;
-	u64 __iomem *invalidate = (u64 __iomem *)tbl->it_index;
+	u64 __iomem *invalidate = rm ?
+		(u64 __iomem *)pe->tce_inval_reg_phys :
+		(u64 __iomem *)tbl->it_index;
 
 	/* We'll invalidate DMA address in PE scope */
 	start = 0x2ul << 60;
@@ -515,22 +533,25 @@ static void pnv_pci_ioda2_tce_invalidate(struct pnv_ioda_pe *pe,
 	mb();
 
 	while (start <= end) {
-		__raw_writeq(start, invalidate);
+		if (rm)
+			__raw_rm_writeq(start, invalidate);
+		else
+			__raw_writeq(start, invalidate);
 		start += inc;
 	}
 }
 
 void pnv_pci_ioda_tce_invalidate(struct iommu_table *tbl,
-				 u64 *startp, u64 *endp)
+				 u64 *startp, u64 *endp, bool rm)
 {
 	struct pnv_ioda_pe *pe = container_of(tbl, struct pnv_ioda_pe,
 					      tce32_table);
 	struct pnv_phb *phb = pe->phb;
 
 	if (phb->type == PNV_PHB_IODA1)
-		pnv_pci_ioda1_tce_invalidate(tbl, startp, endp);
+		pnv_pci_ioda1_tce_invalidate(pe, tbl, startp, endp, rm);
 	else
-		pnv_pci_ioda2_tce_invalidate(pe, tbl, startp, endp);
+		pnv_pci_ioda2_tce_invalidate(pe, tbl, startp, endp, rm);
 }
 
 static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
@@ -603,7 +624,9 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
 		 * bus number, print that out instead.
 		 */
 		tbl->it_busno = 0;
-		tbl->it_index = (unsigned long)ioremap(be64_to_cpup(swinvp), 8);
+		pe->tce_inval_reg_phys = be64_to_cpup(swinvp);
+		tbl->it_index = (unsigned long)ioremap(pe->tce_inval_reg_phys,
+				8);
 		tbl->it_type = TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE |
 			       TCE_PCI_SWINV_PAIR;
 	}
@@ -681,7 +704,9 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 		 * bus number, print that out instead.
 		 */
 		tbl->it_busno = 0;
-		tbl->it_index = (unsigned long)ioremap(be64_to_cpup(swinvp), 8);
+		pe->tce_inval_reg_phys = be64_to_cpup(swinvp);
+		tbl->it_index = (unsigned long)ioremap(pe->tce_inval_reg_phys,
+				8);
 		tbl->it_type = TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE;
 	}
 	iommu_init_table(tbl, phb->hose->node);