skiboot: Find the IMC DTB

IMC (In Memory Collection) catalog is a repository of information
about the Performance Monitoring Units (PMUs) and their events under
the IMC infrastructure. The information include :
 - The PMU names
 - Event names
 - Event description
 - Event offsets
 - Event scale
 - Event unit

The catalog is provided as a flattened device tree (dtb). Processors
with different PVR values may have different PMU or event names. Hence,
for each processor, there can be multiple device tree binaries (dtbs)
containing the IMC information. Each of the dtb is compressed and forms
a sub-partition inside the PNOR partition "IMA_CATALOG". Here is a link
to the commit adding this partition to PNOR :
https://github.com/open-power/pnor/commit/c940142c6dc64dd176096dc648f433c889919e84

So, each compressed dtb forms a sub-partition inside the IMC pnor
partition and can be accessed/loaded through a sub-partition id which
is nothing but the PVR id. Based on the current processor's PVR, the
appropriate sub-partion will be loaded.

Note however, that the catalog information is in the form of a dtb and
the dtb is compressed too. So, the sub-partition loaded must be
decompressed first before we can actually use it.

It is important to mention here that while a PNOR image built for one
processor is specific to only that processor and isn't portable, a
single system generation (Processor version) may have multiple revisions
and these revisions may have some changes in their IMC PMUs and events,
and hence, the need for multiple IMC DTBs.

The sub-partition that we obtain from the IMC pnor partition is a
compressed device tree binary. We uncompress it using the libxz's
functions. After uncompressing it, we link the device tree binary to the
system's device tree. The kernel can now access the device tree and get
the IMC PMUs and their events' information.

Not all the IMC PMUs listed in the device tree may be available. This is
indicated by imc availability vector (which is a part of the IMC control
block structure). We need to check this vector and make sure to remove
the IMC device nodes which are unavailable.

Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com>
Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
[stewart@linux.vnet.ibm.com: use pr_fmt, fix failure path for resource load]
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

1 files changed, 436 insertions, 0 deletions

diff --git a/hw/imc.c b/hw/imc.c
new file mode 100644
index 0000000..bd83048
--- /dev/null
+++ b/hw/imc.c
@@ -0,0 +1,436 @@
+/* Copyright 2016 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#define pr_fmt(fmt)  "IMC: " fmt
+#include <skiboot.h>
+#include <xscom.h>
+#include <imc.h>
+#include <chip.h>
+#include <libxz/xz.h>
+#include <device.h>
+
+/*
+ * Nest IMC PMU names along with their bit values as represented in the
+ * imc_chip_avl_vector(in struct imc_chip_cb, look at include/imc.h).
+ * nest_pmus[] is an array containing all the possible nest IMC PMU node names.
+ */
+char const *nest_pmus[] = {
+	"powerbus0",
+	"mcs0",
+	"mcs1",
+	"mcs2",
+	"mcs3",
+	"mcs4",
+	"mcs5",
+	"mcs6",
+	"mcs7",
+	"mba0",
+	"mba1",
+	"mba2",
+	"mba3",
+	"mba4",
+	"mba5",
+	"mba6",
+	"mba7",
+	"cen0",
+	"cen1",
+	"cen2",
+	"cen3",
+	"cen4",
+	"cen5",
+	"cen6",
+	"cen7",
+	"xlink0",
+	"xlink1",
+	"xlink2",
+	"mcd0",
+	"mcd1",
+	"phb0",
+	"phb1",
+	"phb2",
+	"resvd",
+	"nx",
+	"capp0",
+	"capp1",
+	"vas",
+	"int",
+	"alink0",
+	"alink1",
+	"alink2",
+	"nvlink0",
+	"nvlink1",
+	"nvlink2",
+	"nvlink3",
+	"nvlink4",
+	"nvlink5",
+	/* reserved bits : 48 - 64 */
+};
+
+static char *compress_buf;
+static size_t compress_buf_size;
+const char **prop_to_fix(struct dt_node *node);
+const char *props_to_fix[] = {"events", NULL};
+
+static bool is_nest_mem_initialized(struct imc_chip_cb *ptr)
+{
+	/*
+	 * Non zero value in "Status" field indicate memory initialized.
+	 */
+	if (!ptr->imc_chip_run_status)
+		return false;
+
+	return true;
+}
+
+static struct imc_chip_cb *get_imc_cb(uint32_t chip_id)
+{
+	struct proc_chip *chip = get_chip(chip_id);
+	struct imc_chip_cb *cb;
+
+	cb = (struct imc_chip_cb *)(chip->homer_base + P9_CB_STRUCT_OFFSET);
+	if (!is_nest_mem_initialized(cb))
+		return NULL;
+
+	return cb;
+}
+
+/*
+ * Decompresses the blob obtained from the IMC pnor sub-partition
+ * in "src" of size "src_size", assigns the uncompressed device tree
+ * binary to "dst" and returns.
+ *
+ * Returns 0 on success and -1 on error.
+ *
+ * TODO: Ideally this should be part of generic subpartition load
+ * infrastructure. And decompression can be queued as another CPU job
+ */
+static int decompress(void *dst, size_t dst_size, void *src, size_t src_size)
+{
+	struct xz_dec *s;
+	struct xz_buf b;
+	int ret = 0;
+
+	/* Initialize the xz library first */
+	xz_crc32_init();
+	s = xz_dec_init(XZ_SINGLE, 0);
+	if (s == NULL) {
+		prerror("initialization error for xz\n");
+		return -1;
+	}
+
+	/*
+	 * Source address : src
+	 * Source size : src_size
+	 * Destination address : dst
+	 * Destination size : dst_src
+	 */
+	b.in = src;
+	b.in_pos = 0;
+	b.in_size = src_size;
+	b.out = dst;
+	b.out_pos = 0;
+	b.out_size = dst_size;
+
+	/* Start decompressing */
+	ret = xz_dec_run(s, &b);
+	if (ret != XZ_STREAM_END) {
+		prerror("failed to decompress subpartition\n");
+		ret = -1;
+		goto err;
+	}
+
+	return 0;
+err:
+	/* Clean up memory */
+	xz_dec_end(s);
+	return ret;
+}
+
+/*
+ * Function return list of properties names for the fixup
+ */
+const char **prop_to_fix(struct dt_node *node)
+{
+	if (dt_node_is_compatible(node, "ibm,imc-counters"))
+		return props_to_fix;
+
+	return NULL;
+}
+
+/* Helper to get the IMC device type for a device node */
+static int get_imc_device_type(struct dt_node *node)
+{
+	const struct dt_property *type;
+	u32 val=0;
+
+	if (!node)
+		return -1;
+
+	type = dt_find_property(node, "type");
+	if (!type)
+		return -1;
+
+	val = dt_prop_get_u32(node, "type");
+	switch (val){
+	case IMC_COUNTER_CHIP:
+		return IMC_COUNTER_CHIP;
+	case IMC_COUNTER_CORE:
+		return IMC_COUNTER_CORE;
+	case IMC_COUNTER_THREAD:
+		return IMC_COUNTER_THREAD;
+	default:
+		break;
+	}
+
+	/* Unknown/Unsupported IMC device type */
+	return -1;
+}
+
+static bool is_nest_node(struct dt_node *node)
+{
+	if (get_imc_device_type(node) == IMC_COUNTER_CHIP)
+		return true;
+
+	return false;
+}
+
+static bool is_imc_device_type_supported(struct dt_node *node)
+{
+	u32 val = get_imc_device_type(node);
+
+	if ((val == IMC_COUNTER_CHIP) || (val == IMC_COUNTER_CORE) ||
+						(val == IMC_COUNTER_THREAD))
+		return true;
+
+	return false;
+}
+
+/*
+ * Helper to check for the imc device type in the incoming device tree.
+ * Remove unsupported device node.
+ */
+static void check_imc_device_type(struct dt_node *dev)
+{
+	struct dt_node *node;
+
+	dt_for_each_compatible(dev, node, "ibm,imc-counters") {
+		if (!is_imc_device_type_supported(node)) {
+			/*
+			 * ah nice, found a device type which I didnt know.
+			 * Remove it and also mark node as NULL, since dt_next
+			 * will try to fetch info for "prev" which is removed
+			 * by dt_free.
+			 */
+			dt_free(node);
+			node = NULL;
+		}
+	}
+
+	return;
+}
+
+/*
+ * Remove the PMU device nodes from the incoming new subtree, if they are not
+ * available in the hardware. The availability is described by the
+ * control block's imc_chip_avl_vector.
+ * Each bit represents a device unit. If the device is available, then
+ * the bit is set else its unset.
+ */
+static void disable_unavailable_units(struct dt_node *dev)
+{
+	uint64_t avl_vec;
+	struct imc_chip_cb *cb;
+	struct dt_node *target;
+	int i;
+
+	/* Fetch the IMC control block structure */
+	cb = get_imc_cb(this_cpu()->chip_id);
+	if (cb)
+		avl_vec = be64_to_cpu(cb->imc_chip_avl_vector);
+	else
+		avl_vec = 0; /* Remove only nest imc device nodes */
+
+	for (i = 0; i < MAX_NEST_UNITS; i++) {
+		if (!(PPC_BITMASK(i, i) & avl_vec)) {
+			/* Check if the device node exists */
+			target = dt_find_by_name(dev, nest_pmus[i]);
+			if (!target)
+				continue;
+			/* Remove the device node */
+			dt_free(target);
+		}
+	}
+
+	return;
+}
+
+/*
+ * Function to queue the loading of imc catalog data
+ * from the IMC pnor partition.
+ */
+void imc_catalog_preload(void)
+{
+	uint32_t pvr = (mfspr(SPR_PVR) & ~(0xf000));
+	int ret = OPAL_SUCCESS;
+	compress_buf_size = MAX_COMPRESSED_IMC_DTB_SIZE;
+
+	/* Enable only for power 9 */
+	if (proc_gen != proc_gen_p9)
+		return;
+
+	compress_buf = malloc(MAX_COMPRESSED_IMC_DTB_SIZE);
+	if (!compress_buf) {
+		prerror("Memory allocation for catalog failed\n");
+		return;
+	}
+
+	ret = start_preload_resource(RESOURCE_ID_IMA_CATALOG,
+					pvr, compress_buf, &compress_buf_size);
+	if (ret != OPAL_SUCCESS) {
+		prerror("Failed to load IMA_CATALOG: %d\n", ret);
+		free(compress_buf);
+		compress_buf = NULL;
+	}
+
+	return;
+}
+
+static void imc_dt_update_nest_node(struct dt_node *dev)
+{
+	struct proc_chip *chip;
+	uint64_t *base_addr = NULL;
+	uint32_t *chipids = NULL;
+	int i=0, nr_chip = nr_chips();
+	struct dt_node *node;
+	const struct dt_property *type;
+
+	/* Add the base_addr and chip-id properties for the nest node */
+	base_addr = malloc(sizeof(uint64_t) * nr_chip);
+	chipids = malloc(sizeof(uint32_t) * nr_chip);
+	for_each_chip(chip) {
+		base_addr[i] = chip->homer_base;
+		chipids[i] = chip->id;
+		i++;
+	}
+
+	dt_for_each_compatible(dev, node, "ibm,imc-counters") {
+		type = dt_find_property(node, "type");
+		if (type && is_nest_node(node)) {
+			dt_add_property(node, "base-addr", base_addr, (i * sizeof(u64)));
+			dt_add_property(node, "chip-id", chipids, (i * sizeof(u32)));
+		}
+	}
+}
+
+/*
+ * Load the IMC pnor partition and find the appropriate sub-partition
+ * based on the platform's PVR.
+ * Decompress the sub-partition and link the imc device tree to the
+ * existing device tree.
+ */
+void imc_init(void)
+{
+	void *decompress_buf;
+	uint32_t pvr = (mfspr(SPR_PVR) & ~(0xf000));
+	struct dt_node *dev;
+	int ret;
+
+	/* Enable only for power 9 */
+	if (proc_gen != proc_gen_p9)
+		return;
+
+	/* Check we succeeded in starting the preload */
+	if (compress_buf == NULL)
+		return;
+
+	ret = wait_for_resource_loaded(RESOURCE_ID_IMA_CATALOG, pvr);
+	if (ret != OPAL_SUCCESS) {
+		prerror("IMC Catalog load failed\n");
+		return;
+	}
+
+	/*
+	 * Flow of the data from PNOR to main device tree:
+	 *
+	 * PNOR -> compressed local buffer (compress_buf)
+	 * compressed local buffer -> decompressed local buf (decompress_buf)
+	 * decompress local buffer -> main device tree
+	 * free compressed local buffer
+	 */
+
+	/*
+	 * Memory for decompression.
+	 */
+	decompress_buf = malloc(MAX_DECOMPRESSED_IMC_DTB_SIZE);
+	if (!decompress_buf) {
+		prerror("No memory for decompress_buf \n");
+		goto err;
+	}
+
+	/*
+	 * Decompress the compressed buffer
+	 */
+	ret = decompress(decompress_buf, MAX_DECOMPRESSED_IMC_DTB_SIZE,
+				compress_buf, compress_buf_size);
+	if (ret < 0)
+		goto err;
+
+	/* Create a device tree entry for imc counters */
+	dev = dt_new_root("imc-counters");
+	if (!dev)
+		goto err;
+
+	/*
+	 * Attach the new decompress_buf to the imc-counters node.
+	 * dt_expand_node() does sanity checks for fdt_header, piggyback
+	 */
+	ret = dt_expand_node(dev, decompress_buf, 0);
+	if (ret < 0) {
+		dt_free(dev);
+		goto err;
+	}
+
+	/* Check and remove unsupported imc device types */
+	check_imc_device_type(dev);
+
+	/*
+	 * Check and remove unsupported nest unit nodes by the microcode,
+	 * from the incoming device tree.
+	 */
+	disable_unavailable_units(dev);
+
+	/* Fix the phandle in the incoming device tree */
+	dt_adjust_subtree_phandle(dev, prop_to_fix);
+
+	/* Update the base_addr and chip-id for nest nodes */
+	imc_dt_update_nest_node(dev);
+
+	/*
+	 * If the dt_attach_root() fails, "imc-counters" node will not be
+	 * seen in the device-tree and hence OS should not make any
+	 * OPAL_IMC_* calls.
+	 */
+	if (!dt_attach_root(dt_root, dev)) {
+		dt_free(dev);
+		goto err;
+	}
+
+	free(compress_buf);
+	return;
+err:
+	prerror("IMC Devices not added\n");
+	free(decompress_buf);
+	free(compress_buf);
+}