Message-ID: <fc51344a-9346-ae32-1d88-b8af1fa2bd1f@intel.com>
Date:   Fri, 3 Mar 2023 11:25:03 -0700
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Subject: Re: [PATCH 2/4] cxl/pci: Find and register CXL PMU devices
Content-Language: en-US
To:     Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        linux-cxl@vger.kernel.org
Cc:     peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
        mark.rutland@arm.com, will@kernel.org, dan.j.williams@intel.com,
        bwidawsk@kernel.org, ira.weiny@intel.com, vishal.l.verma@intel.com,
        alison.schofield@intel.com, linuxarm@huawei.com,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230303175022.10806-1-Jonathan.Cameron@huawei.com>
 <20230303175022.10806-3-Jonathan.Cameron@huawei.com>
From:   Dave Jiang <dave.jiang@intel.com>
In-Reply-To: <20230303175022.10806-3-Jonathan.Cameron@huawei.com>
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Precedence: bulk


On 3/3/23 10:50 AM, Jonathan Cameron wrote:
> CXL PMU devices can be found from entries in the Register
> Locator DVSEC.
> 
> In order to register the minimum number of IRQ vectors necessary
> to support all CPMUs found, separate the registration into two
> steps.  First find the devices, and query the IRQs used and then
> register the devices. Between these two steps, request the
> IRQ vectors necessary and enable bus master support.
> 
> Future IRQ users for CXL type 3 devices (e.g. DOEs) will need to
> follow a similar pattern the number of vectors necessary is known
> before any parts of the driver stack rely on their availability.
> 
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>

> ---
> v1 (since RFC v3): thanks to Davidlohr for review.
> - Do not error out if CPMU registration fails.  It is not critical
>    for normal operation.
> - Generally a lot simpler now we don't have to deal with dynamic
>    establishment of the required irq vectors.
> ---
>   drivers/cxl/core/Makefile |  1 +
>   drivers/cxl/core/core.h   |  3 ++
>   drivers/cxl/core/cpmu.c   | 69 +++++++++++++++++++++++++++++++++++++++
>   drivers/cxl/core/port.c   |  2 ++
>   drivers/cxl/core/regs.c   | 16 +++++++++
>   drivers/cxl/cxl.h         | 14 ++++++++
>   drivers/cxl/cxlpci.h      |  1 +
>   drivers/cxl/pci.c         | 25 +++++++++++++-
>   8 files changed, 130 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
> index ca4ae31d8f57..45e5543aff52 100644
> --- a/drivers/cxl/core/Makefile
> +++ b/drivers/cxl/core/Makefile
> @@ -12,5 +12,6 @@ cxl_core-y += memdev.o
>   cxl_core-y += mbox.o
>   cxl_core-y += pci.o
>   cxl_core-y += hdm.o
> +cxl_core-y += cpmu.o
>   cxl_core-$(CONFIG_TRACING) += trace.o
>   cxl_core-$(CONFIG_CXL_REGION) += region.o
> diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
> index cde475e13216..05e18fed3a75 100644
> --- a/drivers/cxl/core/core.h
> +++ b/drivers/cxl/core/core.h
> @@ -17,12 +17,14 @@ extern struct device_attribute dev_attr_region;
>   extern const struct device_type cxl_pmem_region_type;
>   extern const struct device_type cxl_dax_region_type;
>   extern const struct device_type cxl_region_type;
> +extern const struct device_type cxl_cpmu_type;
>   void cxl_decoder_kill_region(struct cxl_endpoint_decoder *cxled);
>   #define CXL_REGION_ATTR(x) (&dev_attr_##x.attr)
>   #define CXL_REGION_TYPE(x) (&cxl_region_type)
>   #define SET_CXL_REGION_ATTR(x) (&dev_attr_##x.attr),
>   #define CXL_PMEM_REGION_TYPE(x) (&cxl_pmem_region_type)
>   #define CXL_DAX_REGION_TYPE(x) (&cxl_dax_region_type)
> +#define CXL_CPMU_TYPE(x) (&cxl_cpmu_region_type)
>   int cxl_region_init(void);
>   void cxl_region_exit(void);
>   #else
> @@ -41,6 +43,7 @@ static inline void cxl_region_exit(void)
>   #define SET_CXL_REGION_ATTR(x)
>   #define CXL_PMEM_REGION_TYPE(x) NULL
>   #define CXL_DAX_REGION_TYPE(x) NULL
> +#define CXL_CPMU_TYPE(x) NULL
>   #endif
>   
>   struct cxl_send_command;
> diff --git a/drivers/cxl/core/cpmu.c b/drivers/cxl/core/cpmu.c
> new file mode 100644
> index 000000000000..cad02f3d43c3
> --- /dev/null
> +++ b/drivers/cxl/core/cpmu.c
> @@ -0,0 +1,69 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/* Copyright(c) 2022 Huawei. All rights reserved. */
> +
> +#include <linux/device.h>
> +#include <linux/slab.h>
> +#include <linux/idr.h>
> +#include <cxlmem.h>
> +#include <cpmu.h>
> +#include <cxl.h>
> +#include "core.h"
> +
> +static DEFINE_IDA(cpmu_ida);
> +
> +static void cxl_cpmu_release(struct device *dev)
> +{
> +	struct cxl_cpmu *cpmu = container_of(dev, struct cxl_cpmu, dev);
> +
> +	ida_free(&cpmu_ida, cpmu->id);
> +	kfree(cpmu);
> +}
> +
> +const struct device_type cxl_cpmu_type = {
> +	.name = "cxl_cpmu",
> +	.release = cxl_cpmu_release,
> +};
> +
> +static void remove_dev(void *dev)
> +{
> +	device_del(dev);
> +}
> +
> +int devm_cxl_cpmu_add(struct device *parent, struct cxl_cpmu_regs *regs, int index)
> +{
> +	struct cxl_cpmu *cpmu;
> +	struct device *dev;
> +	int rc;
> +
> +	cpmu = kzalloc(sizeof(*cpmu), GFP_KERNEL);
> +	if (!cpmu)
> +		return -ENOMEM;
> +
> +	cpmu->base = regs->cpmu;
> +	dev = &cpmu->dev;
> +	device_initialize(dev);
> +	device_set_pm_not_required(dev);
> +	dev->parent = parent;
> +	dev->bus = &cxl_bus_type;
> +	dev->type = &cxl_cpmu_type;
> +	rc = ida_alloc(&cpmu_ida, GFP_KERNEL);
> +	if (rc < 0)
> +		goto err;
> +	cpmu->id = rc;
> +
> +	rc = dev_set_name(dev, "cpmu%d", cpmu->id);
> +	if (rc)
> +		goto err;
> +
> +	rc = device_add(dev);
> +	if (rc)
> +		goto err;
> +
> +	return devm_add_action_or_reset(parent, remove_dev, dev);
> +
> +err:
> +	put_device(&cpmu->dev);
> +	return rc;
> +}
> +EXPORT_SYMBOL_NS_GPL(devm_cxl_cpmu_add, CXL);
> +
> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> index 97cc03dbceee..2154bf8d2aad 100644
> --- a/drivers/cxl/core/port.c
> +++ b/drivers/cxl/core/port.c
> @@ -57,6 +57,8 @@ static int cxl_device_id(const struct device *dev)
>   		return CXL_DEVICE_MEMORY_EXPANDER;
>   	if (dev->type == CXL_REGION_TYPE())
>   		return CXL_DEVICE_REGION;
> +	if (dev->type == &cxl_cpmu_type)
> +		return CXL_DEVICE_CPMU;
>   	return 0;
>   }
>   
> diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
> index 7389dd1af967..99d6ebe3aba9 100644
> --- a/drivers/cxl/core/regs.c
> +++ b/drivers/cxl/core/regs.c
> @@ -6,6 +6,7 @@
>   #include <linux/pci.h>
>   #include <cxlmem.h>
>   #include <cxlpci.h>
> +#include <cpmu.h>
>   
>   #include "core.h"
>   
> @@ -360,6 +361,21 @@ int cxl_count_regblock(struct pci_dev *pdev, enum cxl_regloc_type type)
>   }
>   EXPORT_SYMBOL_NS_GPL(cxl_count_regblock, CXL);
>   
> +int cxl_map_cpmu_regs(struct pci_dev *pdev, struct cxl_cpmu_regs *regs,
> +		      struct cxl_register_map *map)
> +{
> +	struct device *dev = &pdev->dev;
> +	resource_size_t phys_addr;
> +
> +	phys_addr = map->resource;
> +	regs->cpmu = devm_cxl_iomap_block(dev, phys_addr, CPMU_REGMAP_SIZE);
> +	if (!regs->cpmu)
> +		return -ENOMEM;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_map_cpmu_regs, CXL);
> +
>   resource_size_t cxl_rcrb_to_component(struct device *dev,
>   				      resource_size_t rcrb,
>   				      enum cxl_rcrb which)
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 86c4b3cf69d9..62a47d9f0cd3 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -209,6 +209,10 @@ struct cxl_regs {
>   	struct_group_tagged(cxl_device_regs, device_regs,
>   		void __iomem *status, *mbox, *memdev;
>   	);
> +
> +	struct_group_tagged(cxl_cpmu_regs, cpmu_regs,
> +		void __iomem *cpmu;
> +	);
>   };
>   
>   struct cxl_reg_map {
> @@ -229,6 +233,10 @@ struct cxl_device_reg_map {
>   	struct cxl_reg_map memdev;
>   };
>   
> +struct cxl_cpmu_reg_map {
> +	struct cxl_reg_map cpmu;
> +};
> +
>   /**
>    * struct cxl_register_map - DVSEC harvested register block mapping parameters
>    * @base: virtual base of the register-block-BAR + @block_offset
> @@ -237,6 +245,7 @@ struct cxl_device_reg_map {
>    * @reg_type: see enum cxl_regloc_type
>    * @component_map: cxl_reg_map for component registers
>    * @device_map: cxl_reg_maps for device registers
> + * @cpmu_map: cxl_reg_maps for CXL Performance Monitoring Units
>    */
>   struct cxl_register_map {
>   	void __iomem *base;
> @@ -246,6 +255,7 @@ struct cxl_register_map {
>   	union {
>   		struct cxl_component_reg_map component_map;
>   		struct cxl_device_reg_map device_map;
> +		struct cxl_cpmu_reg_map cpmu_map;
>   	};
>   };
>   
> @@ -258,6 +268,8 @@ int cxl_map_component_regs(struct device *dev, struct cxl_component_regs *regs,
>   			   unsigned long map_mask);
>   int cxl_map_device_regs(struct device *dev, struct cxl_device_regs *regs,
>   			struct cxl_register_map *map);
> +int cxl_map_cpmu_regs(struct pci_dev *pdev, struct cxl_cpmu_regs *regs,
> +		      struct cxl_register_map *map);
>   
>   enum cxl_regloc_type;
>   int cxl_count_regblock(struct pci_dev *pdev, enum cxl_regloc_type type);
> @@ -748,6 +760,7 @@ void cxl_driver_unregister(struct cxl_driver *cxl_drv);
>   #define CXL_DEVICE_REGION		6
>   #define CXL_DEVICE_PMEM_REGION		7
>   #define CXL_DEVICE_DAX_REGION		8
> +#define CXL_DEVICE_CPMU			9
>   
>   #define MODULE_ALIAS_CXL(type) MODULE_ALIAS("cxl:t" __stringify(type) "*")
>   #define CXL_MODALIAS_FMT "cxl:t%d"
> @@ -787,6 +800,7 @@ static inline struct cxl_dax_region *to_cxl_dax_region(struct device *dev)
>   }
>   #endif
>   
> +int devm_cxl_cpmu_add(struct device *parent, struct cxl_cpmu_regs *regs, int idx);
>   /*
>    * Unit test builds overrides this to __weak, find the 'strong' version
>    * of these symbols in tools/testing/cxl/.
> diff --git a/drivers/cxl/cxlpci.h b/drivers/cxl/cxlpci.h
> index be6a2ef3cce3..2fd495ab3de1 100644
> --- a/drivers/cxl/cxlpci.h
> +++ b/drivers/cxl/cxlpci.h
> @@ -65,6 +65,7 @@ enum cxl_regloc_type {
>   	CXL_REGLOC_RBI_COMPONENT,
>   	CXL_REGLOC_RBI_VIRT,
>   	CXL_REGLOC_RBI_MEMDEV,
> +	CXL_REGLOC_RBI_CPMU,
>   	CXL_REGLOC_RBI_TYPES
>   };
>   
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index 74443a5c3cc8..e8bc36cc2724 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -704,7 +704,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>   	struct cxl_register_map map;
>   	struct cxl_memdev *cxlmd;
>   	struct cxl_dev_state *cxlds;
> -	int rc;
> +	int i, rc, cpmu_count;
>   
>   	/*
>   	 * Double check the anonymous union trickery in struct cxl_regs
> @@ -781,6 +781,29 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>   	if (rc)
>   		return rc;
>   
> +	cpmu_count = cxl_count_regblock(pdev, CXL_REGLOC_RBI_CPMU);
> +	for (i = 0; i < cpmu_count; i++) {
> +		struct cxl_cpmu_regs cpmu_regs;
> +
> +		rc = cxl_find_regblock(pdev, CXL_REGLOC_RBI_CPMU, &map, i);
> +		if (rc) {
> +			dev_dbg(&pdev->dev, "Could not find CPMU regblock\n");
> +			break;
> +		}
> +
> +		rc = cxl_map_cpmu_regs(pdev, &cpmu_regs, &map);
> +		if (rc) {
> +			dev_dbg(&pdev->dev, "Could not map CPMU regs\n");
> +			break;
> +		}
> +
> +		rc = devm_cxl_cpmu_add(cxlds->dev, &cpmu_regs, i);
> +		if (rc) {
> +			dev_dbg(&pdev->dev, "Could not add CPMU instance\n");
> +			break;
> +		}
> +	}
> +
>   	cxlmd = devm_cxl_add_memdev(cxlds);
>   	if (IS_ERR(cxlmd))
>   		return PTR_ERR(cxlmd);