libata: implement slave_link
Explanation taken from the comment of ata_slave_link_init().
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).
As slave_link excludes PMP support and only code paths which deal with
the attributes of physical link are affected, all the changes are
localized to libata.h, libata-core.c and libata-eh.c.
* ata_is_host_link() updated so that slave_link is considered as host
link too.
* iterator extended to iterate over the slave_link when using the
underbarred version.
* force param handling updated such that devno 16 is mapped to the
slave link/device.
* ata_link_on/offline() updated to return the combined result from
master and slave link. ata_phys_link_on/offline() are the direct
versions.
* EH autopsy and report are performed separately for master slave
links. Reset is udpated to implement the above described reset
sequence.
Except for reset update, most changes are minor, many of them just
modifying dev->link to ata_dev_phys_link(dev) or using phys online
test instead.
After this update, LLDs can take full advantage of per-dev SCR
registers by simply turning on slave link.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index c1db2f2..99037a4 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1756,7 +1756,7 @@
static unsigned int ata_eh_speed_down(struct ata_device *dev,
unsigned int eflags, unsigned int err_mask)
{
- struct ata_link *link = dev->link;
+ struct ata_link *link = ata_dev_phys_link(dev);
int xfer_ok = 0;
unsigned int verdict;
unsigned int action = 0;
@@ -1880,7 +1880,8 @@
for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
- if (!(qc->flags & ATA_QCFLAG_FAILED) || qc->dev->link != link)
+ if (!(qc->flags & ATA_QCFLAG_FAILED) ||
+ ata_dev_phys_link(qc->dev) != link)
continue;
/* inherit upper level err_mask */
@@ -1967,6 +1968,23 @@
ata_port_for_each_link(link, ap)
ata_eh_link_autopsy(link);
+ /* Handle the frigging slave link. Autopsy is done similarly
+ * but actions and flags are transferred over to the master
+ * link and handled from there.
+ */
+ if (ap->slave_link) {
+ struct ata_eh_context *mehc = &ap->link.eh_context;
+ struct ata_eh_context *sehc = &ap->slave_link->eh_context;
+
+ ata_eh_link_autopsy(ap->slave_link);
+
+ ata_eh_about_to_do(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
+ mehc->i.action |= sehc->i.action;
+ mehc->i.dev_action[1] |= sehc->i.dev_action[1];
+ mehc->i.flags |= sehc->i.flags;
+ ata_eh_done(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
+ }
+
/* Autopsy of fanout ports can affect host link autopsy.
* Perform host link autopsy last.
*/
@@ -2001,7 +2019,8 @@
for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
- if (!(qc->flags & ATA_QCFLAG_FAILED) || qc->dev->link != link ||
+ if (!(qc->flags & ATA_QCFLAG_FAILED) ||
+ ata_dev_phys_link(qc->dev) != link ||
((qc->flags & ATA_QCFLAG_QUIET) &&
qc->err_mask == AC_ERR_DEV))
continue;
@@ -2068,7 +2087,7 @@
char cdb_buf[70] = "";
if (!(qc->flags & ATA_QCFLAG_FAILED) ||
- qc->dev->link != link || !qc->err_mask)
+ ata_dev_phys_link(qc->dev) != link || !qc->err_mask)
continue;
if (qc->dma_dir != DMA_NONE) {
@@ -2160,12 +2179,14 @@
}
static int ata_do_reset(struct ata_link *link, ata_reset_fn_t reset,
- unsigned int *classes, unsigned long deadline)
+ unsigned int *classes, unsigned long deadline,
+ bool clear_classes)
{
struct ata_device *dev;
- ata_link_for_each_dev(dev, link)
- classes[dev->devno] = ATA_DEV_UNKNOWN;
+ if (clear_classes)
+ ata_link_for_each_dev(dev, link)
+ classes[dev->devno] = ATA_DEV_UNKNOWN;
return reset(link, classes, deadline);
}
@@ -2187,17 +2208,20 @@
ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
{
struct ata_port *ap = link->ap;
+ struct ata_link *slave = ap->slave_link;
struct ata_eh_context *ehc = &link->eh_context;
+ struct ata_eh_context *sehc = &slave->eh_context;
unsigned int *classes = ehc->classes;
unsigned int lflags = link->flags;
int verbose = !(ehc->i.flags & ATA_EHI_QUIET);
int max_tries = 0, try = 0;
+ struct ata_link *failed_link;
struct ata_device *dev;
unsigned long deadline, now;
ata_reset_fn_t reset;
unsigned long flags;
u32 sstatus;
- int nr_known, rc;
+ int nr_unknown, rc;
/*
* Prepare to reset
@@ -2252,8 +2276,30 @@
}
if (prereset) {
- rc = prereset(link,
- ata_deadline(jiffies, ATA_EH_PRERESET_TIMEOUT));
+ unsigned long deadline = ata_deadline(jiffies,
+ ATA_EH_PRERESET_TIMEOUT);
+
+ if (slave) {
+ sehc->i.action &= ~ATA_EH_RESET;
+ sehc->i.action |= ehc->i.action;
+ }
+
+ rc = prereset(link, deadline);
+
+ /* If present, do prereset on slave link too. Reset
+ * is skipped iff both master and slave links report
+ * -ENOENT or clear ATA_EH_RESET.
+ */
+ if (slave && (rc == 0 || rc == -ENOENT)) {
+ int tmp;
+
+ tmp = prereset(slave, deadline);
+ if (tmp != -ENOENT)
+ rc = tmp;
+
+ ehc->i.action |= sehc->i.action;
+ }
+
if (rc) {
if (rc == -ENOENT) {
ata_link_printk(link, KERN_DEBUG,
@@ -2302,25 +2348,51 @@
else
ehc->i.flags |= ATA_EHI_DID_SOFTRESET;
- rc = ata_do_reset(link, reset, classes, deadline);
- if (rc && rc != -EAGAIN)
+ rc = ata_do_reset(link, reset, classes, deadline, true);
+ if (rc && rc != -EAGAIN) {
+ failed_link = link;
goto fail;
+ }
+ /* hardreset slave link if existent */
+ if (slave && reset == hardreset) {
+ int tmp;
+
+ if (verbose)
+ ata_link_printk(slave, KERN_INFO,
+ "hard resetting link\n");
+
+ ata_eh_about_to_do(slave, NULL, ATA_EH_RESET);
+ tmp = ata_do_reset(slave, reset, classes, deadline,
+ false);
+ switch (tmp) {
+ case -EAGAIN:
+ rc = -EAGAIN;
+ case 0:
+ break;
+ default:
+ failed_link = slave;
+ rc = tmp;
+ goto fail;
+ }
+ }
+
+ /* perform follow-up SRST if necessary */
if (reset == hardreset &&
ata_eh_followup_srst_needed(link, rc, classes)) {
- /* okay, let's do follow-up softreset */
reset = softreset;
if (!reset) {
ata_link_printk(link, KERN_ERR,
"follow-up softreset required "
"but no softreset avaliable\n");
+ failed_link = link;
rc = -EINVAL;
goto fail;
}
ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
- rc = ata_do_reset(link, reset, classes, deadline);
+ rc = ata_do_reset(link, reset, classes, deadline, true);
}
} else {
if (verbose)
@@ -2341,7 +2413,7 @@
dev->pio_mode = XFER_PIO_0;
dev->flags &= ~ATA_DFLAG_SLEEPING;
- if (ata_link_offline(link))
+ if (ata_phys_link_offline(ata_dev_phys_link(dev)))
continue;
/* apply class override */
@@ -2354,6 +2426,8 @@
/* record current link speed */
if (sata_scr_read(link, SCR_STATUS, &sstatus) == 0)
link->sata_spd = (sstatus >> 4) & 0xf;
+ if (slave && sata_scr_read(slave, SCR_STATUS, &sstatus) == 0)
+ slave->sata_spd = (sstatus >> 4) & 0xf;
/* thaw the port */
if (ata_is_host_link(link))
@@ -2366,12 +2440,17 @@
* reset and here. This race is mediated by cross checking
* link onlineness and classification result later.
*/
- if (postreset)
+ if (postreset) {
postreset(link, classes);
+ if (slave)
+ postreset(slave, classes);
+ }
/* clear cached SError */
spin_lock_irqsave(link->ap->lock, flags);
link->eh_info.serror = 0;
+ if (slave)
+ slave->eh_info.serror = 0;
spin_unlock_irqrestore(link->ap->lock, flags);
/* Make sure onlineness and classification result correspond.
@@ -2381,19 +2460,21 @@
* link onlineness and classification result, those conditions
* can be reliably detected and retried.
*/
- nr_known = 0;
+ nr_unknown = 0;
ata_link_for_each_dev(dev, link) {
/* convert all ATA_DEV_UNKNOWN to ATA_DEV_NONE */
- if (classes[dev->devno] == ATA_DEV_UNKNOWN)
+ if (classes[dev->devno] == ATA_DEV_UNKNOWN) {
classes[dev->devno] = ATA_DEV_NONE;
- else
- nr_known++;
+ if (ata_phys_link_online(ata_dev_phys_link(dev)))
+ nr_unknown++;
+ }
}
- if (classify && !nr_known && ata_link_online(link)) {
+ if (classify && nr_unknown) {
if (try < max_tries) {
ata_link_printk(link, KERN_WARNING, "link online but "
"device misclassified, retrying\n");
+ failed_link = link;
rc = -EAGAIN;
goto fail;
}
@@ -2404,6 +2485,8 @@
/* reset successful, schedule revalidation */
ata_eh_done(link, NULL, ATA_EH_RESET);
+ if (slave)
+ ata_eh_done(slave, NULL, ATA_EH_RESET);
ehc->last_reset = jiffies;
ehc->i.action |= ATA_EH_REVALIDATE;
@@ -2411,6 +2494,8 @@
out:
/* clear hotplug flag */
ehc->i.flags &= ~ATA_EHI_HOTPLUGGED;
+ if (slave)
+ sehc->i.flags &= ~ATA_EHI_HOTPLUGGED;
spin_lock_irqsave(ap->lock, flags);
ap->pflags &= ~ATA_PFLAG_RESETTING;
@@ -2431,7 +2516,7 @@
if (time_before(now, deadline)) {
unsigned long delta = deadline - now;
- ata_link_printk(link, KERN_WARNING,
+ ata_link_printk(failed_link, KERN_WARNING,
"reset failed (errno=%d), retrying in %u secs\n",
rc, DIV_ROUND_UP(jiffies_to_msecs(delta), 1000));
@@ -2439,8 +2524,13 @@
delta = schedule_timeout_uninterruptible(delta);
}
- if (rc == -EPIPE || try == max_tries - 1)
+ if (try == max_tries - 1) {
sata_down_spd_limit(link);
+ if (slave)
+ sata_down_spd_limit(slave);
+ } else if (rc == -EPIPE)
+ sata_down_spd_limit(failed_link);
+
if (hardreset)
reset = hardreset;
goto retry;
@@ -2472,7 +2562,7 @@
if ((action & ATA_EH_REVALIDATE) && ata_dev_enabled(dev)) {
WARN_ON(dev->class == ATA_DEV_PMP);
- if (ata_link_offline(link)) {
+ if (ata_phys_link_offline(ata_dev_phys_link(dev))) {
rc = -EIO;
goto err;
}
@@ -2697,7 +2787,7 @@
/* This is the last chance, better to slow
* down than lose it.
*/
- sata_down_spd_limit(dev->link);
+ sata_down_spd_limit(ata_dev_phys_link(dev));
ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
}
}
@@ -2707,7 +2797,7 @@
ata_dev_disable(dev);
/* detach if offline */
- if (ata_link_offline(dev->link))
+ if (ata_phys_link_offline(ata_dev_phys_link(dev)))
ata_eh_detach_dev(dev);
/* schedule probe if necessary */