Commit 9cb26074 authored by James Morse's avatar James Morse Committed by Zeng Heng
Browse files

arm_mpam: Probe MSCs to find the supported partid/pmg values 

maillist inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8T2RT

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/log/?h=mpam/snapshot/v6.7-rc2



---------------------------

CPUs can generate traffic with a range of PARTID and PMG values,
but each MSC may have its own maximum size for these fields.
Before MPAM can be used, the driver needs to probe each RIS on
each MSC, to find the system-wide smallest value that can be used.

While doing this, RIS entries that firmware didn't describe are create
under MPAM_CLASS_UNKNOWN.

Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Signed-off-by: default avatarZeng Heng <zengheng4@huawei.com>
parent 3f4b9c31

arch/arm64/kernel/mpam.c

+10 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 


#include <asm/mpam.h>



#include <linux/arm_mpam.h>

#include <linux/jump_label.h>

#include <linux/percpu.h>
@@ -11,3 +12,12 @@ DEFINE_STATIC_KEY_FALSE(mpam_enabled); 
DEFINE_PER_CPU(u64, arm64_mpam_default);

DEFINE_PER_CPU(u64, arm64_mpam_current);



static int __init arm64_mpam_register_cpus(void)

{

	u64 mpamidr = read_sanitised_ftr_reg(SYS_MPAMIDR_EL1);

	u16 partid_max = FIELD_GET(MPAMIDR_PARTID_MAX, mpamidr);

	u8 pmg_max = FIELD_GET(MPAMIDR_PMG_MAX, mpamidr);



	return mpam_register_requestor(partid_max, pmg_max);

}

arch_initcall(arm64_mpam_register_cpus)

drivers/platform/mpam/mpam_devices.c

+159 −7
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#include <linux/acpi.h>

#include <linux/atomic.h>

#include <linux/arm_mpam.h>

#include <linux/bitfield.h>

#include <linux/cacheinfo.h>

#include <linux/cpu.h>

#include <linux/cpumask.h>
@@ -46,6 +47,15 @@ static u32 mpam_num_msc; 
static int mpam_cpuhp_state;

static DEFINE_MUTEX(mpam_cpuhp_state_lock);



/*

 * The smallest common values for any CPU or MSC in the system.

 * Generating traffic outside this range will result in screaming interrupts.

 */

u16 mpam_partid_max;

u8 mpam_pmg_max;

static bool partid_max_init, partid_max_published;

static DEFINE_SPINLOCK(partid_max_lock);



/*

 * mpam is enabled once all devices have been probed from CPU online callbacks,

 * scheduled via this work_struct. If access to an MSC depends on a CPU that
@@ -79,6 +89,14 @@ static u32 __mpam_read_reg(struct mpam_msc *msc, u16 reg) 
	return readl_relaxed(msc->mapped_hwpage + reg);

}



static void __mpam_write_reg(struct mpam_msc *msc, u16 reg, u32 val)

{

	WARN_ON_ONCE(reg > msc->mapped_hwpage_sz);

	WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility));



	writel_relaxed(val, msc->mapped_hwpage + reg);

}



#define mpam_read_partsel_reg(msc, reg)			\

({							\

	u32 ____ret;					\
@@ -89,6 +107,59 @@ static u32 __mpam_read_reg(struct mpam_msc *msc, u16 reg) 
	____ret;					\

})



#define mpam_write_partsel_reg(msc, reg, val)			\

({								\

	lockdep_assert_held_once(&msc->part_sel_lock);		\

	__mpam_write_reg(msc, MPAMCFG_##reg, val);		\

})



static u64 mpam_msc_read_idr(struct mpam_msc *msc)

{

	u64 idr_high = 0, idr_low;



	lockdep_assert_held(&msc->part_sel_lock);



	idr_low = mpam_read_partsel_reg(msc, IDR);

	if (FIELD_GET(MPAMF_IDR_HAS_EXT, idr_low))

		idr_high = mpam_read_partsel_reg(msc, IDR + 4);



	return (idr_high << 32) | idr_low;

}



static void __mpam_part_sel(u8 ris_idx, u16 partid, struct mpam_msc *msc)

{

	u32 partsel;



	lockdep_assert_held(&msc->part_sel_lock);



	partsel = FIELD_PREP(MPAMCFG_PART_SEL_RIS, ris_idx) |

		  FIELD_PREP(MPAMCFG_PART_SEL_PARTID_SEL, partid);

	mpam_write_partsel_reg(msc, PART_SEL, partsel);

}



int mpam_register_requestor(u16 partid_max, u8 pmg_max)

{

	int err = 0;



	spin_lock(&partid_max_lock);

	if (!partid_max_init) {

		mpam_partid_max = partid_max;

		mpam_pmg_max = pmg_max;

		partid_max_init = true;

	} else if (!partid_max_published) {

		mpam_partid_max = min(mpam_partid_max, partid_max);

		mpam_pmg_max = min(mpam_pmg_max, pmg_max);

	} else {

		/* New requestors can't lower the values */

		if ((partid_max < mpam_partid_max) || (pmg_max < mpam_pmg_max))

			err = -EBUSY;

	}

	spin_unlock(&partid_max_lock);



	return err;

}

EXPORT_SYMBOL(mpam_register_requestor);



static struct mpam_component *

mpam_component_alloc(struct mpam_class *class, int id, gfp_t gfp)

{
@@ -402,6 +473,7 @@ static int mpam_ris_create_locked(struct mpam_msc *msc, u8 ris_idx, 
	cpumask_or(&comp->affinity, &comp->affinity, &ris->affinity);

	cpumask_or(&class->affinity, &class->affinity, &ris->affinity);

	list_add_rcu(&ris->comp_list, &comp->ris);

	list_add_rcu(&ris->msc_list, &msc->ris);



	return 0;

}
@@ -419,10 +491,37 @@ int mpam_ris_create(struct mpam_msc *msc, u8 ris_idx, 
	return err;

}



static struct mpam_msc_ris *mpam_get_or_create_ris(struct mpam_msc *msc,

						   u8 ris_idx)

{

	int err;

	struct mpam_msc_ris *ris, *found = ERR_PTR(-ENOENT);



	lockdep_assert_held(&mpam_list_lock);



	if (!test_bit(ris_idx, msc->ris_idxs)) {

		err = mpam_ris_create_locked(msc, ris_idx, MPAM_CLASS_UNKNOWN,

					     0, 0, GFP_ATOMIC);

		if (err)

			return ERR_PTR(err);

	}



	list_for_each_entry(ris, &msc->ris, msc_list) {

		if (ris->ris_idx == ris_idx) {

			found = ris;

			break;

		}

	}



	return found;

}



static int mpam_msc_hw_probe(struct mpam_msc *msc)

{

	u64 idr;

	int err;

	u16 partid_max;

	u8 ris_idx, pmg_max;

	struct mpam_msc_ris *ris;



	lockdep_assert_held(&msc->lock);
@@ -431,14 +530,43 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc) 
	if ((idr & MPAMF_AIDR_ARCH_MAJOR_REV) != MPAM_ARCHITECTURE_V1) {

		pr_err_once("%s does not match MPAM architecture v1.0\n",

			    dev_name(&msc->pdev->dev));

		err = -EIO;

	} else {

		msc->probed = true;

		err = 0;

		spin_unlock(&msc->part_sel_lock);

		return -EIO;

	}



	idr = mpam_msc_read_idr(msc);

	spin_unlock(&msc->part_sel_lock);

	msc->ris_max = FIELD_GET(MPAMF_IDR_RIS_MAX, idr);



	return err;

	/* Use these values so partid/pmg always starts with a valid value */

	msc->partid_max = FIELD_GET(MPAMF_IDR_PARTID_MAX, idr);

	msc->pmg_max = FIELD_GET(MPAMF_IDR_PMG_MAX, idr);



	for (ris_idx = 0; ris_idx <= msc->ris_max; ris_idx++) {

		spin_lock(&msc->part_sel_lock);

		__mpam_part_sel(ris_idx, 0, msc);

		idr = mpam_msc_read_idr(msc);

		spin_unlock(&msc->part_sel_lock);



		partid_max = FIELD_GET(MPAMF_IDR_PARTID_MAX, idr);

		pmg_max = FIELD_GET(MPAMF_IDR_PMG_MAX, idr);

		msc->partid_max = min(msc->partid_max, partid_max);

		msc->pmg_max = min(msc->pmg_max, pmg_max);



		ris = mpam_get_or_create_ris(msc, ris_idx);

		if (IS_ERR(ris)) {

			return PTR_ERR(ris);

		}

	}



	spin_lock(&partid_max_lock);

	mpam_partid_max = min(mpam_partid_max, msc->partid_max);

	mpam_pmg_max = min(mpam_pmg_max, msc->pmg_max);

	spin_unlock(&partid_max_lock);



	msc->probed = true;



	return 0;

}



static int mpam_cpu_online(unsigned int cpu)
@@ -742,9 +870,18 @@ static void mpam_enable_once(void) 
	mpam_cpuhp_state = 0;

	mutex_unlock(&mpam_cpuhp_state_lock);



	/*

	 * Once the cpuhp callbacks have been changed, mpam_partid_max can no

	 * longer change.

	 */

	spin_lock(&partid_max_lock);

	partid_max_published = true;

	spin_unlock(&partid_max_lock);



	mpam_register_cpuhp_callbacks(mpam_cpu_online);



	pr_info("MPAM enabled\n");

	pr_info("MPAM enabled with %u partid and %u pmg\n",

		mpam_partid_max + 1, mpam_pmg_max + 1);

}



/*
@@ -828,11 +965,25 @@ static void mpam_dt_create_foundling_msc(void) 


static int __init mpam_msc_driver_init(void)

{

	bool mpam_not_available = false;



	if (!mpam_cpus_have_feature())

		return -EOPNOTSUPP;



	init_srcu_struct(&mpam_srcu);



	/*

	 * If the MPAM CPU interface is not implemented, or reserved by

	 * firmware, there is no point touching the rest of the hardware.

	 */

	spin_lock(&partid_max_lock);

	if (!partid_max_init || (!mpam_partid_max && !mpam_pmg_max))

		mpam_not_available = true;

	spin_unlock(&partid_max_lock);



	if (mpam_not_available)

		return 0;



	if (!acpi_disabled)

		fw_num_msc = acpi_mpam_count_msc();

	else
@@ -848,4 +999,5 @@ static int __init mpam_msc_driver_init(void) 


	return platform_driver_register(&mpam_msc_driver);

}

/* Must occur after arm64_mpam_register_cpus() from arch_initcall() */

subsys_initcall(mpam_msc_driver_init);

drivers/platform/mpam/mpam_internal.h

+6 −0
Original line number Diff line number Diff line
@@ -31,6 +31,8 @@ struct mpam_msc 


	struct mutex		lock;

	bool			probed;

	u16			partid_max;

	u8			pmg_max;

	unsigned long		ris_idxs[128 / BITS_PER_LONG];

	u32			ris_max;
@@ -98,6 +100,10 @@ struct mpam_msc_ris 
extern struct list_head mpam_classes;

extern struct srcu_struct mpam_srcu;



/* System wide partid/pmg values */

extern u16 mpam_partid_max;

extern u8 mpam_pmg_max;



/* Scheduled work callback to enable mpam once all MSC have been probed */

void mpam_enable(struct work_struct *work);

include/linux/arm_mpam.h

+2 −0
Original line number Diff line number Diff line
@@ -34,6 +34,8 @@ static inline int acpi_mpam_parse_resources(struct mpam_msc *msc, 
static inline int acpi_mpam_count_msc(void) { return -EINVAL; }

#endif



int mpam_register_requestor(u16 partid_max, u8 pmg_max);



int mpam_ris_create(struct mpam_msc *msc, u8 ris_idx,

		    enum mpam_class_types type, u8 class_id, int component_id);