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Subject[PATCH v3 13/27] powerpc/powernv/pmem: Read the capability registers & wait for device ready
Date
From: Alastair D'Silva <alastair@d-silva.org>

This patch reads timeouts & firmware version from the controller, and
uses those timeouts to wait for the controller to report that it is ready
before handing the memory over to libnvdimm.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
---
arch/powerpc/platforms/powernv/pmem/Makefile | 2 +-
arch/powerpc/platforms/powernv/pmem/ocxl.c | 92 +++++++++++++++++++
.../platforms/powernv/pmem/ocxl_internal.c | 19 ++++
.../platforms/powernv/pmem/ocxl_internal.h | 24 +++++
4 files changed, 136 insertions(+), 1 deletion(-)
create mode 100644 arch/powerpc/platforms/powernv/pmem/ocxl_internal.c

diff --git a/arch/powerpc/platforms/powernv/pmem/Makefile b/arch/powerpc/platforms/powernv/pmem/Makefile
index 1c55c4193175..4ceda25907d4 100644
--- a/arch/powerpc/platforms/powernv/pmem/Makefile
+++ b/arch/powerpc/platforms/powernv/pmem/Makefile
@@ -4,4 +4,4 @@ ccflags-$(CONFIG_PPC_WERROR) += -Werror

obj-$(CONFIG_OCXL_PMEM) += ocxlpmem.o

-ocxlpmem-y := ocxl.o
+ocxlpmem-y := ocxl.o ocxl_internal.o
diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl.c b/arch/powerpc/platforms/powernv/pmem/ocxl.c
index 3c4eeb5dcc0f..431212c9f0cc 100644
--- a/arch/powerpc/platforms/powernv/pmem/ocxl.c
+++ b/arch/powerpc/platforms/powernv/pmem/ocxl.c
@@ -8,6 +8,7 @@

#include <linux/module.h>
#include <misc/ocxl.h>
+#include <linux/delay.h>
#include <linux/ndctl.h>
#include <linux/mm_types.h>
#include <linux/memory_hotplug.h>
@@ -215,6 +216,36 @@ static int register_lpc_mem(struct ocxlpmem *ocxlpmem)
return 0;
}

+/**
+ * is_usable() - Is a controller usable?
+ * @ocxlpmem: the device metadata
+ * @verbose: True to log errors
+ * Return: true if the controller is usable
+ */
+static bool is_usable(const struct ocxlpmem *ocxlpmem, bool verbose)
+{
+ u64 chi = 0;
+ int rc = ocxlpmem_chi(ocxlpmem, &chi);
+
+ if (rc < 0)
+ return false;
+
+ if (!(chi & GLOBAL_MMIO_CHI_CRDY)) {
+ if (verbose)
+ dev_err(&ocxlpmem->dev, "controller is not ready.\n");
+ return false;
+ }
+
+ if (!(chi & GLOBAL_MMIO_CHI_MA)) {
+ if (verbose)
+ dev_err(&ocxlpmem->dev,
+ "controller does not have memory available.\n");
+ return false;
+ }
+
+ return true;
+}
+
/**
* allocate_minor() - Allocate a minor number to use for an OpenCAPI pmem device
* @ocxlpmem: the device metadata
@@ -328,6 +359,48 @@ static void ocxlpmem_remove(struct pci_dev *pdev)
}
}

+/**
+ * read_device_metadata() - Retrieve config information from the AFU and save it for future use
+ * @ocxlpmem: the device metadata
+ * Return: 0 on success, negative on failure
+ */
+static int read_device_metadata(struct ocxlpmem *ocxlpmem)
+{
+ u64 val;
+ int rc;
+
+ rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_CCAP0,
+ OCXL_LITTLE_ENDIAN, &val);
+ if (rc)
+ return rc;
+
+ ocxlpmem->scm_revision = val & 0xFFFF;
+ ocxlpmem->read_latency = (val >> 32) & 0xFF;
+ ocxlpmem->readiness_timeout = (val >> 48) & 0x0F;
+ ocxlpmem->memory_available_timeout = val >> 52;
+
+ rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_CCAP1,
+ OCXL_LITTLE_ENDIAN, &val);
+ if (rc)
+ return rc;
+
+ ocxlpmem->max_controller_dump_size = val & 0xFFFFFFFF;
+
+ // Extract firmware version text
+ rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_FWVER,
+ OCXL_HOST_ENDIAN, (u64 *)ocxlpmem->fw_version);
+ if (rc)
+ return rc;
+
+ ocxlpmem->fw_version[8] = '\0';
+
+ dev_info(&ocxlpmem->dev,
+ "Firmware version '%s' SCM revision %d:%d\n", ocxlpmem->fw_version,
+ ocxlpmem->scm_revision >> 4, ocxlpmem->scm_revision & 0x0F);
+
+ return 0;
+}
+
/**
* probe_function0() - Set up function 0 for an OpenCAPI persistent memory device
* This is important as it enables templates higher than 0 across all other functions,
@@ -368,6 +441,7 @@ static int probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
struct ocxlpmem *ocxlpmem;
int rc;
+ u16 elapsed, timeout;

if (PCI_FUNC(pdev->devfn) == 0)
return probe_function0(pdev);
@@ -422,6 +496,24 @@ static int probe(struct pci_dev *pdev, const struct pci_device_id *ent)
goto err;
}

+ if (read_device_metadata(ocxlpmem)) {
+ dev_err(&pdev->dev, "Could not read metadata\n");
+ goto err;
+ }
+
+ elapsed = 0;
+ timeout = ocxlpmem->readiness_timeout + ocxlpmem->memory_available_timeout;
+ while (!is_usable(ocxlpmem, false)) {
+ if (elapsed++ > timeout) {
+ dev_warn(&ocxlpmem->dev, "OpenCAPI Persistent Memory ready timeout.\n");
+ (void)is_usable(ocxlpmem, true);
+ rc = -ENXIO;
+ goto err;
+ }
+
+ msleep(1000);
+ }
+
rc = register_lpc_mem(ocxlpmem);
if (rc) {
dev_err(&pdev->dev, "Could not register OpenCAPI persistent memory with libnvdimm\n");
diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.c b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.c
new file mode 100644
index 000000000000..617ca943b1b8
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright 2019 IBM Corp.
+
+#include <misc/ocxl.h>
+#include <linux/delay.h>
+#include "ocxl_internal.h"
+
+int ocxlpmem_chi(const struct ocxlpmem *ocxlpmem, u64 *chi)
+{
+ u64 val;
+ int rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_CHI,
+ OCXL_LITTLE_ENDIAN, &val);
+ if (rc)
+ return rc;
+
+ *chi = val;
+
+ return 0;
+}
diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
index 9cf3e42750e7..ba0301533d00 100644
--- a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
+++ b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
@@ -97,4 +97,28 @@ struct ocxlpmem {
void *metadata_addr;
struct resource pmem_res;
struct nd_region *nd_region;
+ char fw_version[8+1];
+
+ u32 max_controller_dump_size;
+ u16 scm_revision; // major/minor
+ u8 readiness_timeout; /* The worst case time (in seconds) that the host shall
+ * wait for the controller to become operational following a reset (CHI.CRDY).
+ */
+ u8 memory_available_timeout; /* The worst case time (in seconds) that the host shall
+ * wait for memory to become available following a reset (CHI.MA).
+ */
+
+ u16 read_latency; /* The nominal measure of latency (in nanoseconds)
+ * associated with an unassisted read of a memory block.
+ * This represents the capability of the raw media technology without assistance
+ */
};
+
+/**
+ * ocxlpmem_chi() - Get the value of the CHI register
+ * @ocxlpmem: the device metadata
+ * @chi: returns the CHI value
+ *
+ * Returns 0 on success, negative on error
+ */
+int ocxlpmem_chi(const struct ocxlpmem *ocxlpmem, u64 *chi);
--
2.24.1
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