1 files changed, 466 insertions, 4 deletions

diff --git a/arch/powerpc/platforms/powernv/npu-dma.c b/arch/powerpc/platforms/powernv/npu-dma.c
index 1c383f38031d..067defeea691 100644
--- a/arch/powerpc/platforms/powernv/npu-dma.c
+++ b/arch/powerpc/platforms/powernv/npu-dma.c
@@ -9,11 +9,20 @@
  * License as published by the Free Software Foundation.
  */
 
+#include <linux/slab.h>
+#include <linux/mmu_notifier.h>
+#include <linux/mmu_context.h>
+#include <linux/of.h>
 #include <linux/export.h>
 #include <linux/pci.h>
 #include <linux/memblock.h>
 #include <linux/iommu.h>
 
+#include <asm/tlb.h>
+#include <asm/powernv.h>
+#include <asm/reg.h>
+#include <asm/opal.h>
+#include <asm/io.h>
 #include <asm/iommu.h>
 #include <asm/pnv-pci.h>
 #include <asm/msi_bitmap.h>
@@ -22,6 +31,8 @@
 #include "powernv.h"
 #include "pci.h"
 
+#define npu_to_phb(x) container_of(x, struct pnv_phb, npu)
+
 /*
  * Other types of TCE cache invalidation are not functional in the
  * hardware.
@@ -37,6 +48,12 @@ struct pci_dev *pnv_pci_get_gpu_dev(struct pci_dev *npdev)
 	struct device_node *dn;
 	struct pci_dev *gpdev;
 
+	if (WARN_ON(!npdev))
+		return NULL;
+
+	if (WARN_ON(!npdev->dev.of_node))
+		return NULL;
+
 	/* Get assoicated PCI device */
 	dn = of_parse_phandle(npdev->dev.of_node, "ibm,gpu", 0);
 	if (!dn)
@@ -55,6 +72,12 @@ struct pci_dev *pnv_pci_get_npu_dev(struct pci_dev *gpdev, int index)
 	struct device_node *dn;
 	struct pci_dev *npdev;
 
+	if (WARN_ON(!gpdev))
+		return NULL;
+
+	if (WARN_ON(!gpdev->dev.of_node))
+		return NULL;
+
 	/* Get assoicated PCI device */
 	dn = of_parse_phandle(gpdev->dev.of_node, "ibm,npu", index);
 	if (!dn)
@@ -180,7 +203,7 @@ long pnv_npu_set_window(struct pnv_ioda_pe *npe, int num,
 		pe_err(npe, "Failed to configure TCE table, err %lld\n", rc);
 		return rc;
 	}
-	pnv_pci_phb3_tce_invalidate_entire(phb, false);
+	pnv_pci_ioda2_tce_invalidate_entire(phb, false);
 
 	/* Add the table to the list so its TCE cache will get invalidated */
 	pnv_pci_link_table_and_group(phb->hose->node, num,
@@ -204,7 +227,7 @@ long pnv_npu_unset_window(struct pnv_ioda_pe *npe, int num)
 		pe_err(npe, "Unmapping failed, ret = %lld\n", rc);
 		return rc;
 	}
-	pnv_pci_phb3_tce_invalidate_entire(phb, false);
+	pnv_pci_ioda2_tce_invalidate_entire(phb, false);
 
 	pnv_pci_unlink_table_and_group(npe->table_group.tables[num],
 			&npe->table_group);
@@ -270,7 +293,7 @@ static int pnv_npu_dma_set_bypass(struct pnv_ioda_pe *npe)
 			0 /* bypass base */, top);
 
 	if (rc == OPAL_SUCCESS)
-		pnv_pci_phb3_tce_invalidate_entire(phb, false);
+		pnv_pci_ioda2_tce_invalidate_entire(phb, false);
 
 	return rc;
 }
@@ -334,7 +357,7 @@ void pnv_npu_take_ownership(struct pnv_ioda_pe *npe)
 		pe_err(npe, "Failed to disable bypass, err %lld\n", rc);
 		return;
 	}
-	pnv_pci_phb3_tce_invalidate_entire(npe->phb, false);
+	pnv_pci_ioda2_tce_invalidate_entire(npe->phb, false);
 }
 
 struct pnv_ioda_pe *pnv_pci_npu_setup_iommu(struct pnv_ioda_pe *npe)
@@ -359,3 +382,442 @@ struct pnv_ioda_pe *pnv_pci_npu_setup_iommu(struct pnv_ioda_pe *npe)
 
 	return gpe;
 }
+
+/* Maximum number of nvlinks per npu */
+#define NV_MAX_LINKS 6
+
+/* Maximum index of npu2 hosts in the system. Always < NV_MAX_NPUS */
+static int max_npu2_index;
+
+struct npu_context {
+	struct mm_struct *mm;
+	struct pci_dev *npdev[NV_MAX_NPUS][NV_MAX_LINKS];
+	struct mmu_notifier mn;
+	struct kref kref;
+
+	/* Callback to stop translation requests on a given GPU */
+	struct npu_context *(*release_cb)(struct npu_context *, void *);
+
+	/*
+	 * Private pointer passed to the above callback for usage by
+	 * device drivers.
+	 */
+	void *priv;
+};
+
+/*
+ * Find a free MMIO ATSD register and mark it in use. Return -ENOSPC
+ * if none are available.
+ */
+static int get_mmio_atsd_reg(struct npu *npu)
+{
+	int i;
+
+	for (i = 0; i < npu->mmio_atsd_count; i++) {
+		if (!test_and_set_bit(i, &npu->mmio_atsd_usage))
+			return i;
+	}
+
+	return -ENOSPC;
+}
+
+static void put_mmio_atsd_reg(struct npu *npu, int reg)
+{
+	clear_bit(reg, &npu->mmio_atsd_usage);
+}
+
+/* MMIO ATSD register offsets */
+#define XTS_ATSD_AVA  1
+#define XTS_ATSD_STAT 2
+
+static int mmio_launch_invalidate(struct npu *npu, unsigned long launch,
+				unsigned long va)
+{
+	int mmio_atsd_reg;
+
+	do {
+		mmio_atsd_reg = get_mmio_atsd_reg(npu);
+		cpu_relax();
+	} while (mmio_atsd_reg < 0);
+
+	__raw_writeq(cpu_to_be64(va),
+		npu->mmio_atsd_regs[mmio_atsd_reg] + XTS_ATSD_AVA);
+	eieio();
+	__raw_writeq(cpu_to_be64(launch), npu->mmio_atsd_regs[mmio_atsd_reg]);
+
+	return mmio_atsd_reg;
+}
+
+static int mmio_invalidate_pid(struct npu *npu, unsigned long pid)
+{
+	unsigned long launch;
+
+	/* IS set to invalidate matching PID */
+	launch = PPC_BIT(12);
+
+	/* PRS set to process-scoped */
+	launch |= PPC_BIT(13);
+
+	/* AP */
+	launch |= (u64) mmu_get_ap(mmu_virtual_psize) << PPC_BITLSHIFT(17);
+
+	/* PID */
+	launch |= pid << PPC_BITLSHIFT(38);
+
+	/* Invalidating the entire process doesn't use a va */
+	return mmio_launch_invalidate(npu, launch, 0);
+}
+
+static int mmio_invalidate_va(struct npu *npu, unsigned long va,
+			unsigned long pid)
+{
+	unsigned long launch;
+
+	/* IS set to invalidate target VA */
+	launch = 0;
+
+	/* PRS set to process scoped */
+	launch |= PPC_BIT(13);
+
+	/* AP */
+	launch |= (u64) mmu_get_ap(mmu_virtual_psize) << PPC_BITLSHIFT(17);
+
+	/* PID */
+	launch |= pid << PPC_BITLSHIFT(38);
+
+	return mmio_launch_invalidate(npu, launch, va);
+}
+
+#define mn_to_npu_context(x) container_of(x, struct npu_context, mn)
+
+/*
+ * Invalidate either a single address or an entire PID depending on
+ * the value of va.
+ */
+static void mmio_invalidate(struct npu_context *npu_context, int va,
+			unsigned long address)
+{
+	int i, j, reg;
+	struct npu *npu;
+	struct pnv_phb *nphb;
+	struct pci_dev *npdev;
+	struct {
+		struct npu *npu;
+		int reg;
+	} mmio_atsd_reg[NV_MAX_NPUS];
+	unsigned long pid = npu_context->mm->context.id;
+
+	/*
+	 * Loop over all the NPUs this process is active on and launch
+	 * an invalidate.
+	 */
+	for (i = 0; i <= max_npu2_index; i++) {
+		mmio_atsd_reg[i].reg = -1;
+		for (j = 0; j < NV_MAX_LINKS; j++) {
+			npdev = npu_context->npdev[i][j];
+			if (!npdev)
+				continue;
+
+			nphb = pci_bus_to_host(npdev->bus)->private_data;
+			npu = &nphb->npu;
+			mmio_atsd_reg[i].npu = npu;
+
+			if (va)
+				mmio_atsd_reg[i].reg =
+					mmio_invalidate_va(npu, address, pid);
+			else
+				mmio_atsd_reg[i].reg =
+					mmio_invalidate_pid(npu, pid);
+
+			/*
+			 * The NPU hardware forwards the shootdown to all GPUs
+			 * so we only have to launch one shootdown per NPU.
+			 */
+			break;
+		}
+	}
+
+	/*
+	 * Unfortunately the nest mmu does not support flushing specific
+	 * addresses so we have to flush the whole mm.
+	 */
+	flush_tlb_mm(npu_context->mm);
+
+	/* Wait for all invalidations to complete */
+	for (i = 0; i <= max_npu2_index; i++) {
+		if (mmio_atsd_reg[i].reg < 0)
+			continue;
+
+		/* Wait for completion */
+		npu = mmio_atsd_reg[i].npu;
+		reg = mmio_atsd_reg[i].reg;
+		while (__raw_readq(npu->mmio_atsd_regs[reg] + XTS_ATSD_STAT))
+			cpu_relax();
+		put_mmio_atsd_reg(npu, reg);
+	}
+}
+
+static void pnv_npu2_mn_release(struct mmu_notifier *mn,
+				struct mm_struct *mm)
+{
+	struct npu_context *npu_context = mn_to_npu_context(mn);
+
+	/* Call into device driver to stop requests to the NMMU */
+	if (npu_context->release_cb)
+		npu_context->release_cb(npu_context, npu_context->priv);
+
+	/*
+	 * There should be no more translation requests for this PID, but we
+	 * need to ensure any entries for it are removed from the TLB.
+	 */
+	mmio_invalidate(npu_context, 0, 0);
+}
+
+static void pnv_npu2_mn_change_pte(struct mmu_notifier *mn,
+				struct mm_struct *mm,
+				unsigned long address,
+				pte_t pte)
+{
+	struct npu_context *npu_context = mn_to_npu_context(mn);
+
+	mmio_invalidate(npu_context, 1, address);
+}
+
+static void pnv_npu2_mn_invalidate_page(struct mmu_notifier *mn,
+					struct mm_struct *mm,
+					unsigned long address)
+{
+	struct npu_context *npu_context = mn_to_npu_context(mn);
+
+	mmio_invalidate(npu_context, 1, address);
+}
+
+static void pnv_npu2_mn_invalidate_range(struct mmu_notifier *mn,
+					struct mm_struct *mm,
+					unsigned long start, unsigned long end)
+{
+	struct npu_context *npu_context = mn_to_npu_context(mn);
+	unsigned long address;
+
+	for (address = start; address <= end; address += PAGE_SIZE)
+		mmio_invalidate(npu_context, 1, address);
+}
+
+static const struct mmu_notifier_ops nv_nmmu_notifier_ops = {
+	.release = pnv_npu2_mn_release,
+	.change_pte = pnv_npu2_mn_change_pte,
+	.invalidate_page = pnv_npu2_mn_invalidate_page,
+	.invalidate_range = pnv_npu2_mn_invalidate_range,
+};
+
+/*
+ * Call into OPAL to setup the nmmu context for the current task in
+ * the NPU. This must be called to setup the context tables before the
+ * GPU issues ATRs. pdev should be a pointed to PCIe GPU device.
+ *
+ * A release callback should be registered to allow a device driver to
+ * be notified that it should not launch any new translation requests
+ * as the final TLB invalidate is about to occur.
+ *
+ * Returns an error if there no contexts are currently available or a
+ * npu_context which should be passed to pnv_npu2_handle_fault().
+ *
+ * mmap_sem must be held in write mode.
+ */
+struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
+			unsigned long flags,
+			struct npu_context *(*cb)(struct npu_context *, void *),
+			void *priv)
+{
+	int rc;
+	u32 nvlink_index;
+	struct device_node *nvlink_dn;
+	struct mm_struct *mm = current->mm;
+	struct pnv_phb *nphb;
+	struct npu *npu;
+	struct npu_context *npu_context;
+
+	/*
+	 * At present we don't support GPUs connected to multiple NPUs and I'm
+	 * not sure the hardware does either.
+	 */
+	struct pci_dev *npdev = pnv_pci_get_npu_dev(gpdev, 0);
+
+	if (!firmware_has_feature(FW_FEATURE_OPAL))
+		return ERR_PTR(-ENODEV);
+
+	if (!npdev)
+		/* No nvlink associated with this GPU device */
+		return ERR_PTR(-ENODEV);
+
+	if (!mm) {
+		/* kernel thread contexts are not supported */
+		return ERR_PTR(-EINVAL);
+	}
+
+	nphb = pci_bus_to_host(npdev->bus)->private_data;
+	npu = &nphb->npu;
+
+	/*
+	 * Setup the NPU context table for a particular GPU. These need to be
+	 * per-GPU as we need the tables to filter ATSDs when there are no
+	 * active contexts on a particular GPU.
+	 */
+	rc = opal_npu_init_context(nphb->opal_id, mm->context.id, flags,
+				PCI_DEVID(gpdev->bus->number, gpdev->devfn));
+	if (rc < 0)
+		return ERR_PTR(-ENOSPC);
+
+	/*
+	 * We store the npu pci device so we can more easily get at the
+	 * associated npus.
+	 */
+	npu_context = mm->context.npu_context;
+	if (!npu_context) {
+		npu_context = kzalloc(sizeof(struct npu_context), GFP_KERNEL);
+		if (!npu_context)
+			return ERR_PTR(-ENOMEM);
+
+		mm->context.npu_context = npu_context;
+		npu_context->mm = mm;
+		npu_context->mn.ops = &nv_nmmu_notifier_ops;
+		__mmu_notifier_register(&npu_context->mn, mm);
+		kref_init(&npu_context->kref);
+	} else {
+		kref_get(&npu_context->kref);
+	}
+
+	npu_context->release_cb = cb;
+	npu_context->priv = priv;
+	nvlink_dn = of_parse_phandle(npdev->dev.of_node, "ibm,nvlink", 0);
+	if (WARN_ON(of_property_read_u32(nvlink_dn, "ibm,npu-link-index",
+							&nvlink_index)))
+		return ERR_PTR(-ENODEV);
+	npu_context->npdev[npu->index][nvlink_index] = npdev;
+
+	return npu_context;
+}
+EXPORT_SYMBOL(pnv_npu2_init_context);
+
+static void pnv_npu2_release_context(struct kref *kref)
+{
+	struct npu_context *npu_context =
+		container_of(kref, struct npu_context, kref);
+
+	npu_context->mm->context.npu_context = NULL;
+	mmu_notifier_unregister(&npu_context->mn,
+				npu_context->mm);
+
+	kfree(npu_context);
+}
+
+void pnv_npu2_destroy_context(struct npu_context *npu_context,
+			struct pci_dev *gpdev)
+{
+	struct pnv_phb *nphb, *phb;
+	struct npu *npu;
+	struct pci_dev *npdev = pnv_pci_get_npu_dev(gpdev, 0);
+	struct device_node *nvlink_dn;
+	u32 nvlink_index;
+
+	if (WARN_ON(!npdev))
+		return;
+
+	if (!firmware_has_feature(FW_FEATURE_OPAL))
+		return;
+
+	nphb = pci_bus_to_host(npdev->bus)->private_data;
+	npu = &nphb->npu;
+	phb = pci_bus_to_host(gpdev->bus)->private_data;
+	nvlink_dn = of_parse_phandle(npdev->dev.of_node, "ibm,nvlink", 0);
+	if (WARN_ON(of_property_read_u32(nvlink_dn, "ibm,npu-link-index",
+							&nvlink_index)))
+		return;
+	npu_context->npdev[npu->index][nvlink_index] = NULL;
+	opal_npu_destroy_context(phb->opal_id, npu_context->mm->context.id,
+				PCI_DEVID(gpdev->bus->number, gpdev->devfn));
+	kref_put(&npu_context->kref, pnv_npu2_release_context);
+}
+EXPORT_SYMBOL(pnv_npu2_destroy_context);
+
+/*
+ * Assumes mmap_sem is held for the contexts associated mm.
+ */
+int pnv_npu2_handle_fault(struct npu_context *context, uintptr_t *ea,
+			unsigned long *flags, unsigned long *status, int count)
+{
+	u64 rc = 0, result = 0;
+	int i, is_write;
+	struct page *page[1];
+
+	/* mmap_sem should be held so the struct_mm must be present */
+	struct mm_struct *mm = context->mm;
+
+	if (!firmware_has_feature(FW_FEATURE_OPAL))
+		return -ENODEV;
+
+	WARN_ON(!rwsem_is_locked(&mm->mmap_sem));
+
+	for (i = 0; i < count; i++) {
+		is_write = flags[i] & NPU2_WRITE;
+		rc = get_user_pages_remote(NULL, mm, ea[i], 1,
+					is_write ? FOLL_WRITE : 0,
+					page, NULL, NULL);
+
+		/*
+		 * To support virtualised environments we will have to do an
+		 * access to the page to ensure it gets faulted into the
+		 * hypervisor. For the moment virtualisation is not supported in
+		 * other areas so leave the access out.
+		 */
+		if (rc != 1) {
+			status[i] = rc;
+			result = -EFAULT;
+			continue;
+		}
+
+		status[i] = 0;
+		put_page(page[0]);
+	}
+
+	return result;
+}
+EXPORT_SYMBOL(pnv_npu2_handle_fault);
+
+int pnv_npu2_init(struct pnv_phb *phb)
+{
+	unsigned int i;
+	u64 mmio_atsd;
+	struct device_node *dn;
+	struct pci_dev *gpdev;
+	static int npu_index;
+	uint64_t rc = 0;
+
+	for_each_child_of_node(phb->hose->dn, dn) {
+		gpdev = pnv_pci_get_gpu_dev(get_pci_dev(dn));
+		if (gpdev) {
+			rc = opal_npu_map_lpar(phb->opal_id,
+				PCI_DEVID(gpdev->bus->number, gpdev->devfn),
+				0, 0);
+			if (rc)
+				dev_err(&gpdev->dev,
+					"Error %lld mapping device to LPAR\n",
+					rc);
+		}
+	}
+
+	for (i = 0; !of_property_read_u64_index(phb->hose->dn, "ibm,mmio-atsd",
+							i, &mmio_atsd); i++)
+		phb->npu.mmio_atsd_regs[i] = ioremap(mmio_atsd, 32);
+
+	pr_info("NPU%lld: Found %d MMIO ATSD registers", phb->opal_id, i);
+	phb->npu.mmio_atsd_count = i;
+	phb->npu.mmio_atsd_usage = 0;
+	npu_index++;
+	if (WARN_ON(npu_index >= NV_MAX_NPUS))
+		return -ENOSPC;
+	max_npu2_index = npu_index;
+	phb->npu.index = npu_index;
+
+	return 0;
+}