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Subject[PATCH v4 13/25] nvdimm/ocxl: Read the capability registers & wait for device ready
Date
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>
---
drivers/nvdimm/ocxl/Makefile | 2 +-
drivers/nvdimm/ocxl/main.c | 85 +++++++++++++++++++++++++
drivers/nvdimm/ocxl/ocxlpmem.h | 29 +++++++++
drivers/nvdimm/ocxl/ocxlpmem_internal.c | 19 ++++++
4 files changed, 134 insertions(+), 1 deletion(-)
create mode 100644 drivers/nvdimm/ocxl/ocxlpmem_internal.c

diff --git a/drivers/nvdimm/ocxl/Makefile b/drivers/nvdimm/ocxl/Makefile
index e0e8ade1987a..bab97082e062 100644
--- a/drivers/nvdimm/ocxl/Makefile
+++ b/drivers/nvdimm/ocxl/Makefile
@@ -4,4 +4,4 @@ ccflags-$(CONFIG_PPC_WERROR) += -Werror

obj-$(CONFIG_OCXL_PMEM) += ocxlpmem.o

-ocxlpmem-y := main.o
\ No newline at end of file
+ocxlpmem-y := main.o ocxlpmem_internal.o
diff --git a/drivers/nvdimm/ocxl/main.c b/drivers/nvdimm/ocxl/main.c
index c0066fedf9cc..be76acd33d74 100644
--- a/drivers/nvdimm/ocxl/main.c
+++ b/drivers/nvdimm/ocxl/main.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>
@@ -327,6 +328,50 @@ static void 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) & 0xFFFF;
+ 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
@@ -359,6 +404,9 @@ static int probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
struct ocxlpmem *ocxlpmem;
int rc;
+ u64 chi;
+ u16 elapsed, timeout;
+ bool ready = false;

if (PCI_FUNC(pdev->devfn) == 0)
return probe_function0(pdev);
@@ -413,6 +461,43 @@ static int probe(struct pci_dev *pdev, const struct pci_device_id *ent)
goto err;
}

+ rc = read_device_metadata(ocxlpmem);
+ if (rc) {
+ dev_err(&pdev->dev, "Could not read metadata\n");
+ goto err;
+ }
+
+ elapsed = 0;
+ timeout = ocxlpmem->readiness_timeout +
+ ocxlpmem->memory_available_timeout;
+
+ while (true) {
+ rc = ocxlpmem_chi(ocxlpmem, &chi);
+ ready = (chi & (GLOBAL_MMIO_CHI_CRDY | GLOBAL_MMIO_CHI_MA)) ==
+ (GLOBAL_MMIO_CHI_CRDY | GLOBAL_MMIO_CHI_MA);
+
+ if (ready)
+ break;
+
+ if (elapsed++ > timeout) {
+ dev_err(&ocxlpmem->dev,
+ "OpenCAPI Persistent Memory ready timeout.\n");
+
+ if (!(chi & GLOBAL_MMIO_CHI_CRDY))
+ dev_err(&ocxlpmem->dev,
+ "controller is not ready.\n");
+
+ if (!(chi & GLOBAL_MMIO_CHI_MA))
+ dev_err(&ocxlpmem->dev,
+ "controller does not have memory available.\n");
+
+ rc = -ENXIO;
+ goto err;
+ }
+
+ msleep(1000);
+ }
+
rc = register_lpc_mem(ocxlpmem);
if (rc) {
dev_err(&pdev->dev,
diff --git a/drivers/nvdimm/ocxl/ocxlpmem.h b/drivers/nvdimm/ocxl/ocxlpmem.h
index 322387873b4b..3eadbe19f6d0 100644
--- a/drivers/nvdimm/ocxl/ocxlpmem.h
+++ b/drivers/nvdimm/ocxl/ocxlpmem.h
@@ -93,4 +93,33 @@ 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);
diff --git a/drivers/nvdimm/ocxl/ocxlpmem_internal.c b/drivers/nvdimm/ocxl/ocxlpmem_internal.c
new file mode 100644
index 000000000000..5578169b7515
--- /dev/null
+++ b/drivers/nvdimm/ocxl/ocxlpmem_internal.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright 2020 IBM Corp.
+
+#include <misc/ocxl.h>
+#include <linux/delay.h>
+#include "ocxlpmem.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;
+}
--
2.24.1
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