hw/npu2-opencapi: Add initial support for allocating OpenCAPI LPC memory

Lowest Point of Coherency (LPC) memory allows the host to access memory on
an OpenCAPI device.

Define 2 OPAL calls, OPAL_NPU_MEM_ALLOC and OPAL_NPU_MEM_RELEASE, for
assigning and clearing the memory BAR. (We try to avoid using the term
"LPC" to avoid confusion with Low Pin Count.)

At present, we use a fixed location in the address space, which means we
are restricted to a single range of 4TB, on a single OpenCAPI device per
chip. In future, we'll use some chip ID extension magic to give us more
space, and some sort of allocator to assign ranges to more than one device.

Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

1 files changed, 181 insertions, 0 deletions

diff --git a/hw/npu2-opencapi.c b/hw/npu2-opencapi.c
index 27dfc12..7a90cfa 100644
--- a/hw/npu2-opencapi.c
+++ b/hw/npu2-opencapi.c
@@ -2025,3 +2025,184 @@ static int64_t opal_npu_tl_set(uint64_t phb_id, uint32_t __unused bdfn,
 	return OPAL_SUCCESS;
 }
 opal_call(OPAL_NPU_TL_SET, opal_npu_tl_set, 5);
+
+static void set_mem_bar(struct npu2_dev *dev, uint64_t base, uint64_t size)
+{
+	uint64_t stack, val, reg, bar_offset, pa_config_offset;
+	uint8_t memsel;
+
+	stack = index_to_stack(dev->brick_index);
+	switch (dev->brick_index) {
+	case 2:
+	case 4:
+		bar_offset = NPU2_GPU0_MEM_BAR;
+		pa_config_offset = NPU2_CQ_CTL_MISC_PA0_CONFIG;
+		break;
+	case 3:
+	case 5:
+		bar_offset = NPU2_GPU1_MEM_BAR;
+		pa_config_offset = NPU2_CQ_CTL_MISC_PA1_CONFIG;
+		break;
+	default:
+		assert(false);
+	}
+
+	assert((!size && !base) || (size && base));
+
+	/*
+	 * Memory select configuration:
+	 * - 0b000 - BAR disabled
+	 * - 0b001 - match 0b00, 0b01
+	 * - 0b010 - match 0b01, 0b10
+	 * - 0b011 - match 0b00, 0b10
+	 * - 0b100 - match 0b00
+	 * - 0b101 - match 0b01
+	 * - 0b110 - match 0b10
+	 * - 0b111 - match 0b00, 0b01, 0b10
+	 */
+	memsel = GETFIELD(PPC_BITMASK(13, 14), base);
+	if (size)
+		val = SETFIELD(NPU2_MEM_BAR_EN | NPU2_MEM_BAR_SEL_MEM, 0ULL, 0b100 + memsel);
+	else
+		val = 0;
+
+	/* Base address - 12 bits, 1G aligned */
+	val = SETFIELD(NPU2_MEM_BAR_NODE_ADDR, val, GETFIELD(PPC_BITMASK(22, 33), base));
+
+	/* GCID */
+	val = SETFIELD(NPU2_MEM_BAR_GROUP, val, GETFIELD(PPC_BITMASK(15, 18), base));
+	val = SETFIELD(NPU2_MEM_BAR_CHIP, val, GETFIELD(PPC_BITMASK(19, 21), base));
+
+	/* Other settings */
+	val = SETFIELD(NPU2_MEM_BAR_POISON, val, 1);
+	val = SETFIELD(NPU2_MEM_BAR_GRANULE, val, 0);
+	val = SETFIELD(NPU2_MEM_BAR_BAR_SIZE, val, ilog2(size >> 30));
+	val = SETFIELD(NPU2_MEM_BAR_MODE, val, 0);
+
+	for (int block = NPU2_BLOCK_SM_0; block <= NPU2_BLOCK_SM_3; block++) {
+		reg = NPU2_REG_OFFSET(stack, block, bar_offset);
+		npu2_write(dev->npu, reg, val);
+	}
+
+	/* Set PA config */
+	if (size)
+		val = SETFIELD(NPU2_CQ_CTL_MISC_PA_CONFIG_MEMSELMATCH, 0ULL, 0b100 + memsel);
+	else
+		val = 0;
+	val = SETFIELD(NPU2_CQ_CTL_MISC_PA_CONFIG_GRANULE, val, 0);
+	val = SETFIELD(NPU2_CQ_CTL_MISC_PA_CONFIG_SIZE, val, ilog2(size >> 30));
+	val = SETFIELD(NPU2_CQ_CTL_MISC_PA_CONFIG_MODE, val, 0);
+	val = SETFIELD(NPU2_CQ_CTL_MISC_PA_CONFIG_MASK, val, 0);
+	reg = NPU2_REG_OFFSET(stack, NPU2_BLOCK_CTL, pa_config_offset);
+	npu2_write(dev->npu, reg, val);
+}
+
+static int64_t alloc_mem_bar(struct npu2_dev *dev, uint64_t size, uint64_t *bar)
+{
+	uint64_t phys_map_base, phys_map_size;
+	int rc = OPAL_SUCCESS;
+
+	lock(&dev->npu->lock);
+
+	/*
+	 * Right now, we support 1 allocation per chip, of up to 4TB.
+	 *
+	 * In future, we will use chip address extension to support
+	 * >4TB ranges, and we will implement a more sophisticated
+	 * allocator to allow an allocation for every link on a chip.
+	 */
+
+	if (dev->npu->lpc_mem_allocated) {
+		rc = OPAL_RESOURCE;
+		goto out;
+	}
+
+	phys_map_get(dev->npu->chip_id, OCAPI_MEM, 0, &phys_map_base, &phys_map_size);
+
+	if (size > phys_map_size) {
+		/**
+		 * @fwts-label OCAPIInvalidLPCMemoryBARSize
+		 * @fwts-advice The operating system requested an unsupported
+		 * amount of OpenCAPI LPC memory. This is possibly a kernel
+		 * bug, or you may need to upgrade your firmware.
+		 */
+		OCAPIERR(dev, "Invalid LPC memory BAR allocation size requested: 0x%llx bytes (limit 0x%llx)\n",
+			 size, phys_map_size);
+		rc = OPAL_PARAMETER;
+		goto out;
+	}
+
+	/* Minimum BAR size is 1 GB */
+	if (size < (1 << 30)) {
+		size = 1 << 30;
+	}
+
+	if (!is_pow2(size)) {
+		size = 1 << (ilog2(size) + 1);
+	}
+
+	set_mem_bar(dev, phys_map_base, size);
+	*bar = phys_map_base;
+	dev->npu->lpc_mem_allocated = dev;
+
+out:
+	unlock(&dev->npu->lock);
+	return rc;
+}
+
+static int64_t release_mem_bar(struct npu2_dev *dev)
+{
+	int rc = OPAL_SUCCESS;
+
+	lock(&dev->npu->lock);
+
+	if (dev->npu->lpc_mem_allocated != dev) {
+		rc = OPAL_PARAMETER;
+		goto out;
+	}
+
+	set_mem_bar(dev, 0, 0);
+	dev->npu->lpc_mem_allocated = NULL;
+
+out:
+	unlock(&dev->npu->lock);
+	return rc;
+}
+
+static int64_t opal_npu_mem_alloc(uint64_t phb_id, uint32_t __unused bdfn,
+				  uint64_t size, uint64_t *bar)
+{
+	struct phb *phb = pci_get_phb(phb_id);
+	struct npu2_dev *dev;
+
+
+	if (!phb || phb->phb_type != phb_type_npu_v2_opencapi)
+		return OPAL_PARAMETER;
+
+	dev = phb_to_npu2_dev_ocapi(phb);
+	if (!dev)
+		return OPAL_PARAMETER;
+
+	if (!opal_addr_valid(bar))
+		return OPAL_PARAMETER;
+
+	return alloc_mem_bar(dev, size, bar);
+}
+opal_call(OPAL_NPU_MEM_ALLOC, opal_npu_mem_alloc, 4);
+
+static int64_t opal_npu_mem_release(uint64_t phb_id, uint32_t __unused bdfn)
+{
+	struct phb *phb = pci_get_phb(phb_id);
+	struct npu2_dev *dev;
+
+
+	if (!phb || phb->phb_type != phb_type_npu_v2_opencapi)
+		return OPAL_PARAMETER;
+
+	dev = phb_to_npu2_dev_ocapi(phb);
+	if (!dev)
+		return OPAL_PARAMETER;
+
+	return release_mem_bar(dev);
+}
+opal_call(OPAL_NPU_MEM_RELEASE, opal_npu_mem_release, 2);