1 files changed, 348 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/npu-dma.c b/arch/powerpc/platforms/powernv/npu-dma.c
new file mode 100644
index 000000000000..e85aa900f5c0
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/npu-dma.c
@@ -0,0 +1,348 @@
+/*
+ * This file implements the DMA operations for NVLink devices. The NPU
+ * devices all point to the same iommu table as the parent PCI device.
+ *
+ * Copyright Alistair Popple, IBM Corporation 2015.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+
+#include <linux/export.h>
+#include <linux/pci.h>
+#include <linux/memblock.h>
+
+#include <asm/iommu.h>
+#include <asm/pnv-pci.h>
+#include <asm/msi_bitmap.h>
+#include <asm/opal.h>
+
+#include "powernv.h"
+#include "pci.h"
+
+/*
+ * Other types of TCE cache invalidation are not functional in the
+ * hardware.
+ */
+#define TCE_KILL_INVAL_ALL PPC_BIT(0)
+
+static struct pci_dev *get_pci_dev(struct device_node *dn)
+{
+	return PCI_DN(dn)->pcidev;
+}
+
+/* Given a NPU device get the associated PCI device. */
+struct pci_dev *pnv_pci_get_gpu_dev(struct pci_dev *npdev)
+{
+	struct device_node *dn;
+	struct pci_dev *gpdev;
+
+	/* Get assoicated PCI device */
+	dn = of_parse_phandle(npdev->dev.of_node, "ibm,gpu", 0);
+	if (!dn)
+		return NULL;
+
+	gpdev = get_pci_dev(dn);
+	of_node_put(dn);
+
+	return gpdev;
+}
+EXPORT_SYMBOL(pnv_pci_get_gpu_dev);
+
+/* Given the real PCI device get a linked NPU device. */
+struct pci_dev *pnv_pci_get_npu_dev(struct pci_dev *gpdev, int index)
+{
+	struct device_node *dn;
+	struct pci_dev *npdev;
+
+	/* Get assoicated PCI device */
+	dn = of_parse_phandle(gpdev->dev.of_node, "ibm,npu", index);
+	if (!dn)
+		return NULL;
+
+	npdev = get_pci_dev(dn);
+	of_node_put(dn);
+
+	return npdev;
+}
+EXPORT_SYMBOL(pnv_pci_get_npu_dev);
+
+#define NPU_DMA_OP_UNSUPPORTED()					\
+	dev_err_once(dev, "%s operation unsupported for NVLink devices\n", \
+		__func__)
+
+static void *dma_npu_alloc(struct device *dev, size_t size,
+			   dma_addr_t *dma_handle, gfp_t flag,
+			   struct dma_attrs *attrs)
+{
+	NPU_DMA_OP_UNSUPPORTED();
+	return NULL;
+}
+
+static void dma_npu_free(struct device *dev, size_t size,
+			 void *vaddr, dma_addr_t dma_handle,
+			 struct dma_attrs *attrs)
+{
+	NPU_DMA_OP_UNSUPPORTED();
+}
+
+static dma_addr_t dma_npu_map_page(struct device *dev, struct page *page,
+				   unsigned long offset, size_t size,
+				   enum dma_data_direction direction,
+				   struct dma_attrs *attrs)
+{
+	NPU_DMA_OP_UNSUPPORTED();
+	return 0;
+}
+
+static int dma_npu_map_sg(struct device *dev, struct scatterlist *sglist,
+			  int nelems, enum dma_data_direction direction,
+			  struct dma_attrs *attrs)
+{
+	NPU_DMA_OP_UNSUPPORTED();
+	return 0;
+}
+
+static int dma_npu_dma_supported(struct device *dev, u64 mask)
+{
+	NPU_DMA_OP_UNSUPPORTED();
+	return 0;
+}
+
+static u64 dma_npu_get_required_mask(struct device *dev)
+{
+	NPU_DMA_OP_UNSUPPORTED();
+	return 0;
+}
+
+struct dma_map_ops dma_npu_ops = {
+	.map_page		= dma_npu_map_page,
+	.map_sg			= dma_npu_map_sg,
+	.alloc			= dma_npu_alloc,
+	.free			= dma_npu_free,
+	.dma_supported		= dma_npu_dma_supported,
+	.get_required_mask	= dma_npu_get_required_mask,
+};
+
+/*
+ * Returns the PE assoicated with the PCI device of the given
+ * NPU. Returns the linked pci device if pci_dev != NULL.
+ */
+static struct pnv_ioda_pe *get_gpu_pci_dev_and_pe(struct pnv_ioda_pe *npe,
+						  struct pci_dev **gpdev)
+{
+	struct pnv_phb *phb;
+	struct pci_controller *hose;
+	struct pci_dev *pdev;
+	struct pnv_ioda_pe *pe;
+	struct pci_dn *pdn;
+
+	if (npe->flags & PNV_IODA_PE_PEER) {
+		pe = npe->peers[0];
+		pdev = pe->pdev;
+	} else {
+		pdev = pnv_pci_get_gpu_dev(npe->pdev);
+		if (!pdev)
+			return NULL;
+
+		pdn = pci_get_pdn(pdev);
+		if (WARN_ON(!pdn || pdn->pe_number == IODA_INVALID_PE))
+			return NULL;
+
+		hose = pci_bus_to_host(pdev->bus);
+		phb = hose->private_data;
+		pe = &phb->ioda.pe_array[pdn->pe_number];
+	}
+
+	if (gpdev)
+		*gpdev = pdev;
+
+	return pe;
+}
+
+void pnv_npu_tce_invalidate_entire(struct pnv_ioda_pe *npe)
+{
+	struct pnv_phb *phb = npe->phb;
+
+	if (WARN_ON(phb->type != PNV_PHB_NPU ||
+		    !phb->ioda.tce_inval_reg ||
+		    !(npe->flags & PNV_IODA_PE_DEV)))
+		return;
+
+	mb(); /* Ensure previous TCE table stores are visible */
+	__raw_writeq(cpu_to_be64(TCE_KILL_INVAL_ALL),
+		phb->ioda.tce_inval_reg);
+}
+
+void pnv_npu_tce_invalidate(struct pnv_ioda_pe *npe,
+				struct iommu_table *tbl,
+				unsigned long index,
+				unsigned long npages,
+				bool rm)
+{
+	struct pnv_phb *phb = npe->phb;
+
+	/* We can only invalidate the whole cache on NPU */
+	unsigned long val = TCE_KILL_INVAL_ALL;
+
+	if (WARN_ON(phb->type != PNV_PHB_NPU ||
+		    !phb->ioda.tce_inval_reg ||
+		    !(npe->flags & PNV_IODA_PE_DEV)))
+		return;
+
+	mb(); /* Ensure previous TCE table stores are visible */
+	if (rm)
+		__raw_rm_writeq(cpu_to_be64(val),
+		  (__be64 __iomem *) phb->ioda.tce_inval_reg_phys);
+	else
+		__raw_writeq(cpu_to_be64(val),
+			phb->ioda.tce_inval_reg);
+}
+
+void pnv_npu_init_dma_pe(struct pnv_ioda_pe *npe)
+{
+	struct pnv_ioda_pe *gpe;
+	struct pci_dev *gpdev;
+	int i, avail = -1;
+
+	if (!npe->pdev || !(npe->flags & PNV_IODA_PE_DEV))
+		return;
+
+	gpe = get_gpu_pci_dev_and_pe(npe, &gpdev);
+	if (!gpe)
+		return;
+
+	for (i = 0; i < PNV_IODA_MAX_PEER_PES; i++) {
+		/* Nothing to do if the PE is already connected. */
+		if (gpe->peers[i] == npe)
+			return;
+
+		if (!gpe->peers[i])
+			avail = i;
+	}
+
+	if (WARN_ON(avail < 0))
+		return;
+
+	gpe->peers[avail] = npe;
+	gpe->flags |= PNV_IODA_PE_PEER;
+
+	/*
+	 * We assume that the NPU devices only have a single peer PE
+	 * (the GPU PCIe device PE).
+	 */
+	npe->peers[0] = gpe;
+	npe->flags |= PNV_IODA_PE_PEER;
+}
+
+/*
+ * For the NPU we want to point the TCE table at the same table as the
+ * real PCI device.
+ */
+static void pnv_npu_disable_bypass(struct pnv_ioda_pe *npe)
+{
+	struct pnv_phb *phb = npe->phb;
+	struct pci_dev *gpdev;
+	struct pnv_ioda_pe *gpe;
+	void *addr;
+	unsigned int size;
+	int64_t rc;
+
+	/*
+	 * Find the assoicated PCI devices and get the dma window
+	 * information from there.
+	 */
+	if (!npe->pdev || !(npe->flags & PNV_IODA_PE_DEV))
+		return;
+
+	gpe = get_gpu_pci_dev_and_pe(npe, &gpdev);
+	if (!gpe)
+		return;
+
+	addr = (void *)gpe->table_group.tables[0]->it_base;
+	size = gpe->table_group.tables[0]->it_size << 3;
+	rc = opal_pci_map_pe_dma_window(phb->opal_id, npe->pe_number,
+					npe->pe_number, 1, __pa(addr),
+					size, 0x1000);
+	if (rc != OPAL_SUCCESS)
+		pr_warn("%s: Error %lld setting DMA window on PHB#%d-PE#%d\n",
+			__func__, rc, phb->hose->global_number, npe->pe_number);
+
+	/*
+	 * We don't initialise npu_pe->tce32_table as we always use
+	 * dma_npu_ops which are nops.
+	 */
+	set_dma_ops(&npe->pdev->dev, &dma_npu_ops);
+}
+
+/*
+ * Enable/disable bypass mode on the NPU. The NPU only supports one
+ * window per link, so bypass needs to be explicity enabled or
+ * disabled. Unlike for a PHB3 bypass and non-bypass modes can't be
+ * active at the same time.
+ */
+int pnv_npu_dma_set_bypass(struct pnv_ioda_pe *npe, bool enable)
+{
+	struct pnv_phb *phb = npe->phb;
+	int64_t rc = 0;
+
+	if (phb->type != PNV_PHB_NPU || !npe->pdev)
+		return -EINVAL;
+
+	if (enable) {
+		/* Enable the bypass window */
+		phys_addr_t top = memblock_end_of_DRAM();
+
+		npe->tce_bypass_base = 0;
+		top = roundup_pow_of_two(top);
+		dev_info(&npe->pdev->dev, "Enabling bypass for PE %d\n",
+			 npe->pe_number);
+		rc = opal_pci_map_pe_dma_window_real(phb->opal_id,
+					npe->pe_number, npe->pe_number,
+					npe->tce_bypass_base, top);
+	} else {
+		/*
+		 * Disable the bypass window by replacing it with the
+		 * TCE32 window.
+		 */
+		pnv_npu_disable_bypass(npe);
+	}
+
+	return rc;
+}
+
+int pnv_npu_dma_set_mask(struct pci_dev *npdev, u64 dma_mask)
+{
+	struct pci_controller *hose = pci_bus_to_host(npdev->bus);
+	struct pnv_phb *phb = hose->private_data;
+	struct pci_dn *pdn = pci_get_pdn(npdev);
+	struct pnv_ioda_pe *npe, *gpe;
+	struct pci_dev *gpdev;
+	uint64_t top;
+	bool bypass = false;
+
+	if (WARN_ON(!pdn || pdn->pe_number == IODA_INVALID_PE))
+		return -ENXIO;
+
+	/* We only do bypass if it's enabled on the linked device */
+	npe = &phb->ioda.pe_array[pdn->pe_number];
+	gpe = get_gpu_pci_dev_and_pe(npe, &gpdev);
+	if (!gpe)
+		return -ENODEV;
+
+	if (gpe->tce_bypass_enabled) {
+		top = gpe->tce_bypass_base + memblock_end_of_DRAM() - 1;
+		bypass = (dma_mask >= top);
+	}
+
+	if (bypass)
+		dev_info(&npdev->dev, "Using 64-bit DMA iommu bypass\n");
+	else
+		dev_info(&npdev->dev, "Using 32-bit DMA via iommu\n");
+
+	pnv_npu_dma_set_bypass(npe, bypass);
+	*npdev->dev.dma_mask = dma_mask;
+
+	return 0;
+}