[mirror_ubuntu-jammy-kernel.git] / drivers / ata / libata-sata.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  SATA specific part of ATA helper library
 *
 *  Copyright 2003-2004 Red Hat, Inc.  All rights reserved.
 *  Copyright 2003-2004 Jeff Garzik
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/libata.h>

#include "libata.h"

/**
 *      sata_scr_valid - test whether SCRs are accessible
 *      @link: ATA link to test SCR accessibility for
 *
 *      Test whether SCRs are accessible for @link.
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      1 if SCRs are accessible, 0 otherwise.
 */
int sata_scr_valid(struct ata_link *link)
{
        struct ata_port *ap = link->ap;

        return (ap->flags & ATA_FLAG_SATA) && ap->ops->scr_read;
}
EXPORT_SYMBOL_GPL(sata_scr_valid);

/**
 *      sata_scr_read - read SCR register of the specified port
 *      @link: ATA link to read SCR for
 *      @reg: SCR to read
 *      @val: Place to store read value
 *
 *      Read SCR register @reg of @link into *@val.  This function is
 *      guaranteed to succeed if @link is ap->link, the cable type of
 *      the port is SATA and the port implements ->scr_read.
 *
 *      LOCKING:
 *      None if @link is ap->link.  Kernel thread context otherwise.
 *
 *      RETURNS:
 *      0 on success, negative errno on failure.
 */
int sata_scr_read(struct ata_link *link, int reg, u32 *val)
{
        if (ata_is_host_link(link)) {
                if (sata_scr_valid(link))
                        return link->ap->ops->scr_read(link, reg, val);
                return -EOPNOTSUPP;
        }

        return sata_pmp_scr_read(link, reg, val);
}
EXPORT_SYMBOL_GPL(sata_scr_read);

/**
 *      sata_scr_write - write SCR register of the specified port
 *      @link: ATA link to write SCR for
 *      @reg: SCR to write
 *      @val: value to write
 *
 *      Write @val to SCR register @reg of @link.  This function is
 *      guaranteed to succeed if @link is ap->link, the cable type of
 *      the port is SATA and the port implements ->scr_read.
 *
 *      LOCKING:
 *      None if @link is ap->link.  Kernel thread context otherwise.
 *
 *      RETURNS:
 *      0 on success, negative errno on failure.
 */
int sata_scr_write(struct ata_link *link, int reg, u32 val)
{
        if (ata_is_host_link(link)) {
                if (sata_scr_valid(link))
                        return link->ap->ops->scr_write(link, reg, val);
                return -EOPNOTSUPP;
        }

        return sata_pmp_scr_write(link, reg, val);
}
EXPORT_SYMBOL_GPL(sata_scr_write);

/**
 *      sata_scr_write_flush - write SCR register of the specified port and flush
 *      @link: ATA link to write SCR for
 *      @reg: SCR to write
 *      @val: value to write
 *
 *      This function is identical to sata_scr_write() except that this
 *      function performs flush after writing to the register.
 *
 *      LOCKING:
 *      None if @link is ap->link.  Kernel thread context otherwise.
 *
 *      RETURNS:
 *      0 on success, negative errno on failure.
 */
int sata_scr_write_flush(struct ata_link *link, int reg, u32 val)
{
        if (ata_is_host_link(link)) {
                int rc;

                if (sata_scr_valid(link)) {
                        rc = link->ap->ops->scr_write(link, reg, val);
                        if (rc == 0)
                                rc = link->ap->ops->scr_read(link, reg, &val);
                        return rc;
                }
                return -EOPNOTSUPP;
        }

        return sata_pmp_scr_write(link, reg, val);
}
EXPORT_SYMBOL_GPL(sata_scr_write_flush);

/**
 *      ata_tf_to_fis - Convert ATA taskfile to SATA FIS structure
 *      @tf: Taskfile to convert
 *      @pmp: Port multiplier port
 *      @is_cmd: This FIS is for command
 *      @fis: Buffer into which data will output
 *
 *      Converts a standard ATA taskfile to a Serial ATA
 *      FIS structure (Register - Host to Device).
 *
 *      LOCKING:
 *      Inherited from caller.
 */
void ata_tf_to_fis(const struct ata_taskfile *tf, u8 pmp, int is_cmd, u8 *fis)
{
        fis[0] = 0x27;                  /* Register - Host to Device FIS */
        fis[1] = pmp & 0xf;             /* Port multiplier number*/
        if (is_cmd)
                fis[1] |= (1 << 7);     /* bit 7 indicates Command FIS */

        fis[2] = tf->command;
        fis[3] = tf->feature;

        fis[4] = tf->lbal;
        fis[5] = tf->lbam;
        fis[6] = tf->lbah;
        fis[7] = tf->device;

        fis[8] = tf->hob_lbal;
        fis[9] = tf->hob_lbam;
        fis[10] = tf->hob_lbah;
        fis[11] = tf->hob_feature;

        fis[12] = tf->nsect;
        fis[13] = tf->hob_nsect;
        fis[14] = 0;
        fis[15] = tf->ctl;

        fis[16] = tf->auxiliary & 0xff;
        fis[17] = (tf->auxiliary >> 8) & 0xff;
        fis[18] = (tf->auxiliary >> 16) & 0xff;
        fis[19] = (tf->auxiliary >> 24) & 0xff;
}
EXPORT_SYMBOL_GPL(ata_tf_to_fis);

/**
 *      ata_tf_from_fis - Convert SATA FIS to ATA taskfile
 *      @fis: Buffer from which data will be input
 *      @tf: Taskfile to output
 *
 *      Converts a serial ATA FIS structure to a standard ATA taskfile.
 *
 *      LOCKING:
 *      Inherited from caller.
 */

void ata_tf_from_fis(const u8 *fis, struct ata_taskfile *tf)
{
        tf->command     = fis[2];       /* status */
        tf->feature     = fis[3];       /* error */

        tf->lbal        = fis[4];
        tf->lbam        = fis[5];
        tf->lbah        = fis[6];
        tf->device      = fis[7];

        tf->hob_lbal    = fis[8];
        tf->hob_lbam    = fis[9];
        tf->hob_lbah    = fis[10];

        tf->nsect       = fis[12];
        tf->hob_nsect   = fis[13];
}
EXPORT_SYMBOL_GPL(ata_tf_from_fis);

/**
 *      sata_link_scr_lpm - manipulate SControl IPM and SPM fields
 *      @link: ATA link to manipulate SControl for
 *      @policy: LPM policy to configure
 *      @spm_wakeup: initiate LPM transition to active state
 *
 *      Manipulate the IPM field of the SControl register of @link
 *      according to @policy.  If @policy is ATA_LPM_MAX_POWER and
 *      @spm_wakeup is %true, the SPM field is manipulated to wake up
 *      the link.  This function also clears PHYRDY_CHG before
 *      returning.
 *
 *      LOCKING:
 *      EH context.
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int sata_link_scr_lpm(struct ata_link *link, enum ata_lpm_policy policy,
                      bool spm_wakeup)
{
        struct ata_eh_context *ehc = &link->eh_context;
        bool woken_up = false;
        u32 scontrol;
        int rc;

        rc = sata_scr_read(link, SCR_CONTROL, &scontrol);
        if (rc)
                return rc;

        switch (policy) {
        case ATA_LPM_MAX_POWER:
                /* disable all LPM transitions */
                scontrol |= (0x7 << 8);
                /* initiate transition to active state */
                if (spm_wakeup) {
                        scontrol |= (0x4 << 12);
                        woken_up = true;
                }
                break;
        case ATA_LPM_MED_POWER:
                /* allow LPM to PARTIAL */
                scontrol &= ~(0x1 << 8);
                scontrol |= (0x6 << 8);
                break;
        case ATA_LPM_MED_POWER_WITH_DIPM:
        case ATA_LPM_MIN_POWER_WITH_PARTIAL:
        case ATA_LPM_MIN_POWER:
                if (ata_link_nr_enabled(link) > 0)
                        /* no restrictions on LPM transitions */
                        scontrol &= ~(0x7 << 8);
                else {
                        /* empty port, power off */
                        scontrol &= ~0xf;
                        scontrol |= (0x1 << 2);
                }
                break;
        default:
                WARN_ON(1);
        }

        rc = sata_scr_write(link, SCR_CONTROL, scontrol);
        if (rc)
                return rc;

        /* give the link time to transit out of LPM state */
        if (woken_up)
                msleep(10);

        /* clear PHYRDY_CHG from SError */
        ehc->i.serror &= ~SERR_PHYRDY_CHG;
        return sata_scr_write(link, SCR_ERROR, SERR_PHYRDY_CHG);
}
EXPORT_SYMBOL_GPL(sata_link_scr_lpm);

static int __sata_set_spd_needed(struct ata_link *link, u32 *scontrol)
{
        struct ata_link *host_link = &link->ap->link;
        u32 limit, target, spd;

        limit = link->sata_spd_limit;

        /* Don't configure downstream link faster than upstream link.
         * It doesn't speed up anything and some PMPs choke on such
         * configuration.
         */
        if (!ata_is_host_link(link) && host_link->sata_spd)
                limit &= (1 << host_link->sata_spd) - 1;

        if (limit == UINT_MAX)
                target = 0;
        else
                target = fls(limit);

        spd = (*scontrol >> 4) & 0xf;
        *scontrol = (*scontrol & ~0xf0) | ((target & 0xf) << 4);

        return spd != target;
}

/**
 *      sata_set_spd_needed - is SATA spd configuration needed
 *      @link: Link in question
 *
 *      Test whether the spd limit in SControl matches
 *      @link->sata_spd_limit.  This function is used to determine
 *      whether hardreset is necessary to apply SATA spd
 *      configuration.
 *
 *      LOCKING:
 *      Inherited from caller.
 *
 *      RETURNS:
 *      1 if SATA spd configuration is needed, 0 otherwise.
 */
int sata_set_spd_needed(struct ata_link *link)
{
        u32 scontrol;

        if (sata_scr_read(link, SCR_CONTROL, &scontrol))
                return 1;

        return __sata_set_spd_needed(link, &scontrol);
}

/**
 *      sata_set_spd - set SATA spd according to spd limit
 *      @link: Link to set SATA spd for
 *
 *      Set SATA spd of @link according to sata_spd_limit.
 *
 *      LOCKING:
 *      Inherited from caller.
 *
 *      RETURNS:
 *      0 if spd doesn't need to be changed, 1 if spd has been
 *      changed.  Negative errno if SCR registers are inaccessible.
 */
int sata_set_spd(struct ata_link *link)
{
        u32 scontrol;
        int rc;

        if ((rc = sata_scr_read(link, SCR_CONTROL, &scontrol)))
                return rc;

        if (!__sata_set_spd_needed(link, &scontrol))
                return 0;

        if ((rc = sata_scr_write(link, SCR_CONTROL, scontrol)))
                return rc;

        return 1;
}
EXPORT_SYMBOL_GPL(sata_set_spd);

/**
 *      ata_slave_link_init - initialize slave link
 *      @ap: port to initialize slave link for
 *
 *      Create and initialize slave link for @ap.  This enables slave
 *      link handling on the port.
 *
 *      In libata, a port contains links and a link contains devices.
 *      There is single host link but if a PMP is attached to it,
 *      there can be multiple fan-out links.  On SATA, there's usually
 *      a single device connected to a link but PATA and SATA
 *      controllers emulating TF based interface can have two - master
 *      and slave.
 *
 *      However, there are a few controllers which don't fit into this
 *      abstraction too well - SATA controllers which emulate TF
 *      interface with both master and slave devices but also have
 *      separate SCR register sets for each device.  These controllers
 *      need separate links for physical link handling
 *      (e.g. onlineness, link speed) but should be treated like a
 *      traditional M/S controller for everything else (e.g. command
 *      issue, softreset).
 *
 *      slave_link is libata's way of handling this class of
 *      controllers without impacting core layer too much.  For
 *      anything other than physical link handling, the default host
 *      link is used for both master and slave.  For physical link
 *      handling, separate @ap->slave_link is used.  All dirty details
 *      are implemented inside libata core layer.  From LLD's POV, the
 *      only difference is that prereset, hardreset and postreset are
 *      called once more for the slave link, so the reset sequence
 *      looks like the following.
 *
 *      prereset(M) -> prereset(S) -> hardreset(M) -> hardreset(S) ->
 *      softreset(M) -> postreset(M) -> postreset(S)
 *
 *      Note that softreset is called only for the master.  Softreset
 *      resets both M/S by definition, so SRST on master should handle
 *      both (the standard method will work just fine).
 *
 *      LOCKING:
 *      Should be called before host is registered.
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
int ata_slave_link_init(struct ata_port *ap)
{
        struct ata_link *link;

        WARN_ON(ap->slave_link);
        WARN_ON(ap->flags & ATA_FLAG_PMP);

        link = kzalloc(sizeof(*link), GFP_KERNEL);
        if (!link)
                return -ENOMEM;

        ata_link_init(ap, link, 1);
        ap->slave_link = link;
        return 0;
}
EXPORT_SYMBOL_GPL(ata_slave_link_init);

/**
 *      sata_lpm_ignore_phy_events - test if PHY event should be ignored
 *      @link: Link receiving the event
 *
 *      Test whether the received PHY event has to be ignored or not.
 *
 *      LOCKING:
 *      None:
 *
 *      RETURNS:
 *      True if the event has to be ignored.
 */
bool sata_lpm_ignore_phy_events(struct ata_link *link)
{
        unsigned long lpm_timeout = link->last_lpm_change +
                                    msecs_to_jiffies(ATA_TMOUT_SPURIOUS_PHY);

        /* if LPM is enabled, PHYRDY doesn't mean anything */
        if (link->lpm_policy > ATA_LPM_MAX_POWER)
                return true;

        /* ignore the first PHY event after the LPM policy changed
         * as it is might be spurious
         */
        if ((link->flags & ATA_LFLAG_CHANGED) &&
            time_before(jiffies, lpm_timeout))
                return true;

        return false;
}
EXPORT_SYMBOL_GPL(sata_lpm_ignore_phy_events);