[Skiboot] [PATCH v5 3/8] skiboot: Find the IMC DTB
Oliver O'Halloran
oohall at gmail.com
Fri Feb 10 17:58:10 AEDT 2017
On Wed, 2017-02-08 at 02:41 +0530, Hemant Kumar wrote:
> 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/c940142c6dc64dd176096dc648f
> 433c889919e84
>
> So, each compressed dtb forms a sub-partition inside the IMA_CATALOG
> 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.
>
> IMA_CATALOG
> partition
> ----------- Sub-id (E.g)
> | |
> |Catalog 1| 0x100
> |---------|
> | |
> |Catalog 2| 0x200 <------ Current processor's PVR (0x200)
> |---------|
> ...
>
> In the above example, if the current processor's PVR is 0x200,
> catalog 2
> should 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 (which is done in
> subsequent patches).
>
> 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 IMA_CATALOG 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 at linux.vnet.ibm.com>
> ---
> Chaneglog:
> v2 -> v3:
> - Clubbed patch 2 and patch 4 from v2 into one.
> - Changed references from IMA to IMC.
> - Uses proc_gen now to check for power9.
> - Uses macro MAX_AVL instead of 48.
> - Reworked a segment of the code to disable the unavailable nest
> units
> first and then attach the final IMC device tree to the system dt.
> - Created a new helper get_imc_cb() to fetch the nest IMC control
> block
> struct.
> - Use of be64_to_cpu() to read data from control block.
> v1 -> v2:
> - Moved the macro checks for power8 to a separate function
> is_power8().
> - Added a new function disable_unavailable_units() to check the IMA
> availability vector and remove the nest PMU nodes from the device
> tree.
>
> core/flash.c | 1 +
> core/init.c | 4 ++
> hw/Makefile.inc | 2 +-
> hw/imc.c | 188
> +++++++++++++++++++++++++++++++++++++++++++++++++++++
> include/imc.h | 2 +
> include/platform.h | 1 +
> 6 files changed, 197 insertions(+), 1 deletion(-)
> create mode 100644 hw/imc.c
>
> diff --git a/core/flash.c b/core/flash.c
> index 92de421..32b32dc 100644
> --- a/core/flash.c
> +++ b/core/flash.c
> @@ -416,6 +416,7 @@ static struct {
> { RESOURCE_ID_KERNEL, RESOURCE_SUBID_NONE,
> "BOOTKERNEL" },
> { RESOURCE_ID_INITRAMFS,RESOURCE_SUBID_NONE,
> "ROOTFS" },
> { RESOURCE_ID_CAPP, RESOURCE_SUBID_SUPPORTED,
> "CAPP" },
> + { RESOURCE_ID_CATALOG, RESOURCE_SUBID_SUPPORTED, "IM
> A_CATALOG" },
I suppose it's too late to rename this to IMC_CATALOG?
> };
>
> /* This mimics the hostboot SBE format */
> diff --git a/core/init.c b/core/init.c
> index 43ce3a0..07f4568 100644
> --- a/core/init.c
> +++ b/core/init.c
> @@ -47,6 +47,7 @@
> #include <nvram.h>
> #include <libstb/stb.h>
> #include <libstb/container.h>
> +#include <imc.h>
>
> enum proc_gen proc_gen;
>
> @@ -903,6 +904,9 @@ void __noreturn __nomcount main_cpu_entry(const
> void *fdt)
> /* Init SLW related stuff, including fastsleep */
> slw_init();
>
> + /* Init IMA related stuff (load the IMA dtb into memory) */
> + imc_init();
> +
> op_display(OP_LOG, OP_MOD_INIT, 0x0002);
>
> /* Read in NVRAM and set it up */
> diff --git a/hw/Makefile.inc b/hw/Makefile.inc
> index a433c2b..02a9c72 100644
> --- a/hw/Makefile.inc
> +++ b/hw/Makefile.inc
> @@ -1,7 +1,7 @@
> # -*-Makefile-*-
> SUBDIRS += hw
> HW_OBJS = xscom.o chiptod.o gx.o cec.o lpc.o lpc-uart.o psi.o
> -HW_OBJS += homer.o slw.o occ.o fsi-master.o centaur.o
> +HW_OBJS += homer.o slw.o occ.o fsi-master.o centaur.o imc.o
> HW_OBJS += nx.o nx-rng.o nx-crypto.o nx-842.o
> HW_OBJS += p7ioc.o p7ioc-inits.o p7ioc-phb.o
> HW_OBJS += phb3.o sfc-ctrl.o fake-rtc.o bt.o p8-i2c.o prd.o
> diff --git a/hw/imc.c b/hw/imc.c
> new file mode 100644
> index 0000000..f0eca7b
> --- /dev/null
> +++ b/hw/imc.c
> @@ -0,0 +1,188 @@
> +/* 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.
> + */
> +
> +#include <skiboot.h>
> +#include <xscom.h>
> +#include <imc.h>
> +#include <chip.h>
> +#include <libxz/xz.h>
> +#include <nest_imc.h>
> +
> +static struct imc_chip_cb *get_imc_cb(void)
> +{
> + uint64_t cb_loc;
> + struct proc_chip *chip = get_chip(this_cpu()->chip_id);
> +
> + cb_loc = chip->homer_base + CB_STRUCT_OFFSET;
> + return (struct imc_chip_cb *)cb_loc;
> +}
> +
> +/*
> + * Decompresses the blob obtained from the IMA_CATALOG sub-partition
> + * in "buf" of size "size", assigns the uncompressed device tree
> + * binary to "fdt" and returns.
> + * Returns 0 on success and -1 on error.
> + */
> +static int decompress_subpartition(char *buf, size_t size, void
> **fdt)
> +{
> + struct xz_dec *s;
> + struct xz_buf b;
> + void *data;
> + int ret = 0;
> +
> + /* Initialize the xz library first */
> + xz_crc32_init();
> + s = xz_dec_init(XZ_SINGLE, 0);
> + if (s == NULL)
> + {
> + prerror("IMC: initialization error for xz\n");
> + return -1;
> + }
> +
> + /* Allocate memory for the uncompressed data */
> + data = malloc(IMC_DTB_SIZE);
> + if (!data) {
> + prerror("IMC: memory allocation error\n");
> + ret = -1;
> + goto err;
> + }
> +
> + /*
> + * Source address : buf
> + * Source size : size
> + * Destination address : data
> + * Destination size : IMC_DTB_SIZE
> + */
> + b.in = buf;
> + b.in_pos = 0;
> + b.in_size = size;
> + b.out = data;
> + b.out_pos = 0;
> + b.out_size = IMC_DTB_SIZE;
> +
> + /* Start decompressing */
> + ret = xz_dec_run(s, &b);
> + if (ret != XZ_STREAM_END) {
> + prerror("IMC: failed to decompress subpartition\n");
> + free(data);
> + ret = -1;
> + }
> + *fdt = data;
> +
> +err:
> + /* Clean up memory */
> + xz_dec_end(s);
> + return ret;
> +}
> +
> +/*
> + * Remove the PMU device nodes from the system's dt, if they are not
I don't think this should be "from the system's dt"
+ * 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 int disable_unavailable_units(void)
> +{
> + 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();
> +
> + avl_vec = be64_to_cpu(cb->imc_chip_avl_vector);
> + for (i = 0; i < MAX_AVL; i++) {
> + if (!(PPC_BITMASK(i, i) & avl_vec)) {
> + /* Check if the device node exists */
> + target = dt_find_by_name(dt_root,
> nest_pmus[i]);
I don't think you want to be looking at dt_root here. Isn't this
function supposed to prune the unflattened IMC DT? If so we should pass
it its root as a function argument.
> + if (!target)
> + continue;
> + /* Remove the device node */
> + dt_free(target);
> + }
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * Fetch the IMA_CATALOG 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)
> +{
> + char *buf = NULL;
> + size_t size = IMC_DTB_SIZE;
> + uint32_t pvr = mfspr(SPR_PVR);
> + int ret;
> + struct dt_node *dev;
> + void *fdt = NULL;
> +
> + /* Enable only for power 9 */
> + if (proc_gen != proc_gen_p9)
> + return;
> +
> + buf = malloc(IMC_DTB_SIZE);
> + if (!buf) {
> + prerror("IMC: unable to allocate memory\n");
> + return;
> + }
> +
> + ret = start_preload_resource(RESOURCE_ID_CATALOG,
> + pvr, buf, &size);
> + if (ret != OPAL_SUCCESS)
> + goto err;
> +
> + ret = wait_for_resource_loaded(RESOURCE_ID_CATALOG,
> + pvr);
> + if (ret != OPAL_SUCCESS) {
> + prerror("IMC: unable to load the catalog\n");
> + goto err;
> + }
We should probably provide a helper for this, but that can be fixed
another day.
> +
> + /* Decompress the subpartition now */
> + ret = decompress_subpartition(buf, size, &fdt);
> + if (ret < 0) {
> + goto err;
> + }
> +
> + /* Create a device tree entry for imc counters */
> + dev = dt_new_root("imc-counters");
> + if (!dev) {
> + prerror("IMC: Unable to create device node\n");
> + goto err;
> + }
> +
> + /* Attach the new fdt to the imc-counters node */
> + ret = dt_expand_node(dev, fdt, 0);
> + if (ret < 0)
> + prerror("IMC: device tree couldn't be linked\n");
> +
> + /* Check availability of the PMU units from the availability
> vector */
> + ret = disable_unavailable_units();
See my comments above. We should be passing dev into
disable_unavailable_units().
> + if (ret < 0)
> + prerror("IMC: error in disabling unavailable
> units\n");
> + if (!dt_attach_root(dt_root, dev)) {
> + prerror("IMC: error in attaching IMC dt to system
> dt\n");
> + dt_free(dev);
> + }
> +err:
> + free(buf);
> +}
> diff --git a/include/imc.h b/include/imc.h
> index d6f765a..b44c0c2 100644
> --- a/include/imc.h
> +++ b/include/imc.h
> @@ -112,4 +112,6 @@ struct imc_chip_cb
> #define NEST_IMC_ENABLE 0x1
> #define NEST_IMC_DISABLE 0x2
>
> +void imc_init(void);
> +
> #endif /* __IMC_H */
> diff --git a/include/platform.h b/include/platform.h
> index 334c0a4..02adb2f 100644
> --- a/include/platform.h
> +++ b/include/platform.h
> @@ -27,6 +27,7 @@ enum resource_id {
> RESOURCE_ID_KERNEL,
> RESOURCE_ID_INITRAMFS,
> RESOURCE_ID_CAPP,
> + RESOURCE_ID_CATALOG,
> };
> #define RESOURCE_SUBID_NONE 0
> #define RESOURCE_SUBID_SUPPORTED 1
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