cregit-Linux how code gets into the kernel

Release 4.7 drivers/infiniband/hw/hfi1/aspm.h

/*
 * Copyright(c) 2015, 2016 Intel Corporation.
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * BSD LICENSE
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *  - Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  - Neither the name of Intel Corporation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#ifndef _ASPM_H

#define _ASPM_H

#include "hfi.h"

extern uint aspm_mode;


enum aspm_mode {
	
ASPM_MODE_DISABLED = 0,	/* ASPM always disabled, performance mode */
	
ASPM_MODE_ENABLED = 1,	/* ASPM always enabled, power saving mode */
	
ASPM_MODE_DYNAMIC = 2,	/* ASPM enabled/disabled dynamically */
};

/* Time after which the timer interrupt will re-enable ASPM */

#define ASPM_TIMER_MS 1000
/* Time for which interrupts are ignored after a timer has been scheduled */

#define ASPM_RESCHED_TIMER_MS (ASPM_TIMER_MS / 2)
/* Two interrupts within this time trigger ASPM disable */

#define ASPM_TRIGGER_MS 1

#define ASPM_TRIGGER_NS (ASPM_TRIGGER_MS * 1000 * 1000ull)

#define ASPM_L1_SUPPORTED(reg) \
	(((reg & PCI_EXP_LNKCAP_ASPMS) >> 10) & 0x2)


static inline bool aspm_hw_l1_supported(struct hfi1_devdata *dd) { struct pci_dev *parent = dd->pcidev->bus->self; u32 up, dn; /* * If the driver does not have access to the upstream component, * it cannot support ASPM L1 at all. */ if (!parent) return false; pcie_capability_read_dword(dd->pcidev, PCI_EXP_LNKCAP, &dn); dn = ASPM_L1_SUPPORTED(dn); pcie_capability_read_dword(parent, PCI_EXP_LNKCAP, &up); up = ASPM_L1_SUPPORTED(up); /* ASPM works on A-step but is reported as not supported */ return (!!dn || is_ax(dd)) && !!up; }

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/* Set L1 entrance latency for slower entry to L1 */
static inline void aspm_hw_set_l1_ent_latency(struct hfi1_devdata *dd) { u32 l1_ent_lat = 0x4u; u32 reg32; pci_read_config_dword(dd->pcidev, PCIE_CFG_REG_PL3, &reg32); reg32 &= ~PCIE_CFG_REG_PL3_L1_ENT_LATENCY_SMASK; reg32 |= l1_ent_lat << PCIE_CFG_REG_PL3_L1_ENT_LATENCY_SHIFT; pci_write_config_dword(dd->pcidev, PCIE_CFG_REG_PL3, reg32); }

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static inline void aspm_hw_enable_l1(struct hfi1_devdata *dd) { struct pci_dev *parent = dd->pcidev->bus->self; /* * If the driver does not have access to the upstream component, * it cannot support ASPM L1 at all. */ if (!parent) return; /* Enable ASPM L1 first in upstream component and then downstream */ pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_ASPMC, PCI_EXP_LNKCTL_ASPM_L1); pcie_capability_clear_and_set_word(dd->pcidev, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_ASPMC, PCI_EXP_LNKCTL_ASPM_L1); }

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static inline void aspm_hw_disable_l1(struct hfi1_devdata *dd) { struct pci_dev *parent = dd->pcidev->bus->self; /* Disable ASPM L1 first in downstream component and then upstream */ pcie_capability_clear_and_set_word(dd->pcidev, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_ASPMC, 0x0); if (parent) pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_ASPMC, 0x0); }

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static inline void aspm_enable(struct hfi1_devdata *dd) { if (dd->aspm_enabled || aspm_mode == ASPM_MODE_DISABLED || !dd->aspm_supported) return; aspm_hw_enable_l1(dd); dd->aspm_enabled = true; }

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static inline void aspm_disable(struct hfi1_devdata *dd) { if (!dd->aspm_enabled || aspm_mode == ASPM_MODE_ENABLED) return; aspm_hw_disable_l1(dd); dd->aspm_enabled = false; }

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static inline void aspm_disable_inc(struct hfi1_devdata *dd) { unsigned long flags; spin_lock_irqsave(&dd->aspm_lock, flags); aspm_disable(dd); atomic_inc(&dd->aspm_disabled_cnt); spin_unlock_irqrestore(&dd->aspm_lock, flags); }

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static inline void aspm_enable_dec(struct hfi1_devdata *dd) { unsigned long flags; spin_lock_irqsave(&dd->aspm_lock, flags); if (atomic_dec_and_test(&dd->aspm_disabled_cnt)) aspm_enable(dd); spin_unlock_irqrestore(&dd->aspm_lock, flags); }

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/* ASPM processing for each receive context interrupt */
static inline void aspm_ctx_disable(struct hfi1_ctxtdata *rcd) { bool restart_timer; bool close_interrupts; unsigned long flags; ktime_t now, prev; /* Quickest exit for minimum impact */ if (!rcd->aspm_intr_supported) return; spin_lock_irqsave(&rcd->aspm_lock, flags); /* PSM contexts are open */ if (!rcd->aspm_intr_enable) goto unlock; prev = rcd->aspm_ts_last_intr; now = ktime_get(); rcd->aspm_ts_last_intr = now; /* An interrupt pair close together in time */ close_interrupts = ktime_to_ns(ktime_sub(now, prev)) < ASPM_TRIGGER_NS; /* Don't push out our timer till this much time has elapsed */ restart_timer = ktime_to_ns(ktime_sub(now, rcd->aspm_ts_timer_sched)) > ASPM_RESCHED_TIMER_MS * NSEC_PER_MSEC; restart_timer = restart_timer && close_interrupts; /* Disable ASPM and schedule timer */ if (rcd->aspm_enabled && close_interrupts) { aspm_disable_inc(rcd->dd); rcd->aspm_enabled = false; restart_timer = true; } if (restart_timer) { mod_timer(&rcd->aspm_timer, jiffies + msecs_to_jiffies(ASPM_TIMER_MS)); rcd->aspm_ts_timer_sched = now; } unlock: spin_unlock_irqrestore(&rcd->aspm_lock, flags); }

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/* Timer function for re-enabling ASPM in the absence of interrupt activity */
static inline void aspm_ctx_timer_function(unsigned long data) { struct hfi1_ctxtdata *rcd = (struct hfi1_ctxtdata *)data; unsigned long flags; spin_lock_irqsave(&rcd->aspm_lock, flags); aspm_enable_dec(rcd->dd); rcd->aspm_enabled = true; spin_unlock_irqrestore(&rcd->aspm_lock, flags); }

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/* Disable interrupt processing for verbs contexts when PSM contexts are open */
static inline void aspm_disable_all(struct hfi1_devdata *dd) { struct hfi1_ctxtdata *rcd; unsigned long flags; unsigned i; for (i = 0; i < dd->first_user_ctxt; i++) { rcd = dd->rcd[i]; del_timer_sync(&rcd->aspm_timer); spin_lock_irqsave(&rcd->aspm_lock, flags); rcd->aspm_intr_enable = false; spin_unlock_irqrestore(&rcd->aspm_lock, flags); } aspm_disable(dd); atomic_set(&dd->aspm_disabled_cnt, 0); }

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/* Re-enable interrupt processing for verbs contexts */
static inline void aspm_enable_all(struct hfi1_devdata *dd) { struct hfi1_ctxtdata *rcd; unsigned long flags; unsigned i; aspm_enable(dd); if (aspm_mode != ASPM_MODE_DYNAMIC) return; for (i = 0; i < dd->first_user_ctxt; i++) { rcd = dd->rcd[i]; spin_lock_irqsave(&rcd->aspm_lock, flags); rcd->aspm_intr_enable = true; rcd->aspm_enabled = true; spin_unlock_irqrestore(&rcd->aspm_lock, flags); } }

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static inline void aspm_ctx_init(struct hfi1_ctxtdata *rcd) { spin_lock_init(&rcd->aspm_lock); setup_timer(&rcd->aspm_timer, aspm_ctx_timer_function, (unsigned long)rcd); rcd->aspm_intr_supported = rcd->dd->aspm_supported && aspm_mode == ASPM_MODE_DYNAMIC && rcd->ctxt < rcd->dd->first_user_ctxt; }

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static inline void aspm_init(struct hfi1_devdata *dd) { unsigned i; spin_lock_init(&dd->aspm_lock); dd->aspm_supported = aspm_hw_l1_supported(dd); for (i = 0; i < dd->first_user_ctxt; i++) aspm_ctx_init(dd->rcd[i]); /* Start with ASPM disabled */ aspm_hw_set_l1_ent_latency(dd); dd->aspm_enabled = false; aspm_hw_disable_l1(dd); /* Now turn on ASPM if configured */ aspm_enable_all(dd); }

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static inline void aspm_exit(struct hfi1_devdata *dd) { aspm_disable_all(dd); /* Turn on ASPM on exit to conserve power */ aspm_enable(dd); }

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#endif /* _ASPM_H */

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