[PATCHSET 01/03] prep for hotplug support, take 4

[PATCHSET 01/03] prep for hotplug support, take 4

[Tejun Heo]

Hello,

This is This is part of patchset series described in [T].

This is the fourth take of prep-for-hotplug-support patchset.  Changes
from the last take[L] are.

* ATA_FLAG_CANT_WAIT_FIS34 renamed to ATA_FLAG_SKIP_D2H_BSY

* make-ops->tf_read()-optional patch killed

* implement-ata_noop_check_status() patch killed

* better comments for ATA_DEVICE_CLEAR_OFFSET

* ata_hotplug_wq renamed to ata_scsi_wq

* wrap calls to sata_*() from ata_*() under 'if (ap->cbl == SATA)'
  condition

This patchset is against

  upstream (ef2824073fba9def3cf122e89cc485f66dd71f70)
  + [1] set-PIO-0-after-successful-EH-reset

Thanks.

--
tejun

[T] http://article.gmane.org/gmane.linux.ide/10891
[L] http://article.gmane.org/gmane.linux.ide/10546
[1] http://article.gmane.org/gmane.linux.ide/10890

[PATCH 01/12] libata-hp-prep: add flags and eh_info/context fields for hotplug

[Tejun Heo]

Add hotplug related flags and eh_info/context fields.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 include/linux/libata.h |   19 ++++++++++++++++++-
 1 files changed, 18 insertions(+), 1 deletions(-)

5577bff1743157fb00b7499d832dd55c47245e3e
diff --git a/include/linux/libata.h b/include/linux/libata.h
index b0ee1c1..4f67c43 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -131,6 +131,9 @@ enum {
 
 	ATA_DFLAG_PIO		= (1 << 8), /* device currently in PIO mode */
 
+	ATA_DFLAG_DETACH	= (1 << 16),
+	ATA_DFLAG_DETACHED	= (1 << 17),
+
 	ATA_DEV_UNKNOWN		= 0,	/* unknown device */
 	ATA_DEV_ATA		= 1,	/* ATA device */
 	ATA_DEV_ATA_UNSUP	= 2,	/* ATA device (unsupported) */
@@ -152,6 +155,9 @@ enum {
 	ATA_FLAG_PIO_POLLING	= (1 << 10), /* use polling PIO if LLD
 					      * doesn't handle PIO interrupts */
 	ATA_FLAG_NCQ		= (1 << 11), /* host supports NCQ */
+	ATA_FLAG_HRST_TO_RESUME	= (1 << 12), /* hardreset to resume phy */
+	ATA_FLAG_SKIP_D2H_BSY	= (1 << 13), /* can't wait for the first D2H
+					      * Register FIS clearing BSY */
 
 	ATA_FLAG_DEBUGMSG	= (1 << 14),
 	ATA_FLAG_FLUSH_PORT_TASK = (1 << 15), /* flush port task */
@@ -159,6 +165,9 @@ enum {
 	ATA_FLAG_EH_PENDING	= (1 << 16), /* EH pending */
 	ATA_FLAG_FROZEN		= (1 << 17), /* port is frozen */
 	ATA_FLAG_RECOVERED	= (1 << 18), /* recovery action performed */
+	ATA_FLAG_LOADING	= (1 << 19), /* boot/loading probe */
+	ATA_FLAG_UNLOADING	= (1 << 20), /* module is unloading */
+	ATA_FLAG_SCSI_HOTPLUG	= (1 << 21), /* SCSI hotplug scheduled */
 
 	ATA_FLAG_DISABLED	= (1 << 22), /* port is disabled, ignore it */
 	ATA_FLAG_SUSPENDED	= (1 << 23), /* port is suspended (power) */
@@ -240,7 +249,9 @@ enum {
 	ATA_EH_RESET_MASK	= ATA_EH_SOFTRESET | ATA_EH_HARDRESET,
 
 	/* ata_eh_info->flags */
-	ATA_EHI_DID_RESET	= (1 << 0), /* already reset this port */
+	ATA_EHI_HOTPLUGGED	= (1 << 0),  /* could have been hotplugged */
+
+	ATA_EHI_DID_RESET	= (1 << 16), /* already reset this port */
 
 	/* max repeat if error condition is still set after ->error_handler */
 	ATA_EH_MAX_REPEAT	= 5,
@@ -433,6 +444,10 @@ struct ata_eh_info {
 	unsigned int		err_mask;	/* port-wide err_mask */
 	unsigned int		action;		/* ATA_EH_* action mask */
 	unsigned int		flags;		/* ATA_EHI_* flags */
+
+	unsigned long		hotplug_timestamp;
+	unsigned int		probe_mask;
+
 	char			desc[ATA_EH_DESC_LEN];
 	int			desc_len;
 };
@@ -440,6 +455,8 @@ struct ata_eh_info {
 struct ata_eh_context {
 	struct ata_eh_info	i;
 	int			tries[ATA_MAX_DEVICES];
+	unsigned int		classes[ATA_MAX_DEVICES];
+	unsigned int		did_probe_mask;
 };
 
 struct ata_port {
-- 
1.3.2

[PATCH 02/12] libata-hp-prep: implement ata_dev_init()

[Tejun Heo]

Move initialization of struct ata_device into ata_dev_init() in
preparation for hotplug.  This patch calls ata_dev_init() from
ata_host_init() and thus makes no functional difference.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/libata-core.c |   26 +++++++++++++++++++++-----
 drivers/scsi/libata.h      |    1 +
 2 files changed, 22 insertions(+), 5 deletions(-)

1b63513233c45c44f359191b2e854e090f404e69
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 11df827..84afb59 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -5142,6 +5142,26 @@ static void ata_host_remove(struct ata_p
 }
 
 /**
+ *	ata_dev_init - Initialize an ata_device structure
+ *	@dev: Device structure to initialize
+ *
+ *	Initialize @dev in preparation for probing.
+ *
+ *	LOCKING:
+ *	Inherited from caller.
+ */
+void ata_dev_init(struct ata_device *dev)
+{
+	struct ata_port *ap = dev->ap;
+
+	memset((void *)dev, 0, sizeof(*dev));
+	dev->devno = dev - ap->device;
+	dev->pio_mask = UINT_MAX;
+	dev->mwdma_mask = UINT_MAX;
+	dev->udma_mask = UINT_MAX;
+}
+
+/**
  *	ata_host_init - Initialize an ata_port structure
  *	@ap: Structure to initialize
  *	@host: associated SCSI mid-layer structure
@@ -5155,7 +5175,6 @@ static void ata_host_remove(struct ata_p
  *	LOCKING:
  *	Inherited from caller.
  */
-
 static void ata_host_init(struct ata_port *ap, struct Scsi_Host *host,
 			  struct ata_host_set *host_set,
 			  const struct ata_probe_ent *ent, unsigned int port_no)
@@ -5198,10 +5217,7 @@ static void ata_host_init(struct ata_por
 	for (i = 0; i < ATA_MAX_DEVICES; i++) {
 		struct ata_device *dev = &ap->device[i];
 		dev->ap = ap;
-		dev->devno = i;
-		dev->pio_mask = UINT_MAX;
-		dev->mwdma_mask = UINT_MAX;
-		dev->udma_mask = UINT_MAX;
+		ata_dev_init(dev);
 	}
 
 #ifdef ATA_IRQ_TRAP
diff --git a/drivers/scsi/libata.h b/drivers/scsi/libata.h
index b76ad7d..d46c552 100644
--- a/drivers/scsi/libata.h
+++ b/drivers/scsi/libata.h
@@ -62,6 +62,7 @@ extern int ata_check_atapi_dma(struct at
 extern void ata_dev_select(struct ata_port *ap, unsigned int device,
                            unsigned int wait, unsigned int can_sleep);
 extern void swap_buf_le16(u16 *buf, unsigned int buf_words);
+extern void ata_dev_init(struct ata_device *dev);
 extern int ata_task_ioctl(struct scsi_device *scsidev, void __user *arg);
 extern int ata_cmd_ioctl(struct scsi_device *scsidev, void __user *arg);
 
-- 
1.3.2

[PATCH 09/12] libata-hp-prep: make probing related functions global

[Tejun Heo]

Hotplug will be implemented in libata-eh.c.  Make ata_dev_read_id()
and ata_dev_configure() global.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/libata-core.c |    6 +++---
 drivers/scsi/libata.h      |    3 +++
 2 files changed, 6 insertions(+), 3 deletions(-)

a0fe7eb0b738cb74416f362a956e8593bfd3a0c0
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index aa1e0a1..009db45 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1167,8 +1167,8 @@ unsigned int ata_pio_need_iordy(const st
  *	RETURNS:
  *	0 on success, -errno otherwise.
  */
-static int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class,
-			   int post_reset, u16 *id)
+int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class,
+		    int post_reset, u16 *id)
 {
 	struct ata_port *ap = dev->ap;
 	unsigned int class = *p_class;
@@ -1292,7 +1292,7 @@ static void ata_dev_config_ncq(struct at
  *	RETURNS:
  *	0 on success, -errno otherwise
  */
-static int ata_dev_configure(struct ata_device *dev, int print_info)
+int ata_dev_configure(struct ata_device *dev, int print_info)
 {
 	struct ata_port *ap = dev->ap;
 	const u16 *id = dev->id;
diff --git a/drivers/scsi/libata.h b/drivers/scsi/libata.h
index d4bb2e4..e3f7406 100644
--- a/drivers/scsi/libata.h
+++ b/drivers/scsi/libata.h
@@ -50,6 +50,9 @@ extern void ata_port_flush_task(struct a
 extern unsigned ata_exec_internal(struct ata_device *dev,
 				  struct ata_taskfile *tf, const u8 *cdb,
 				  int dma_dir, void *buf, unsigned int buflen);
+extern int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class,
+			   int post_reset, u16 *id);
+extern int ata_dev_configure(struct ata_device *dev, int print_info);
 extern int sata_down_spd_limit(struct ata_port *ap);
 extern int sata_set_spd_needed(struct ata_port *ap);
 extern int ata_down_xfermask_limit(struct ata_device *dev, int force_pio0);
-- 
1.3.2

Re: [PATCH 09/12] libata-hp-prep: make probing related functions global

[Jeff Garzik]

Tejun Heo wrote:
> Hotplug will be implemented in libata-eh.c.  Make ata_dev_read_id()
> and ata_dev_configure() global.
> 
> Signed-off-by: Tejun Heo <htejun@gmail.com>

ACK 8-9

[PATCH 08/12] libata-hp-prep: add ata_scsi_wq

[Tejun Heo]

It's best to run ATA hotplug from EH but attaching SCSI devices needs
working EH.  ata_scsi_wq is used to give SCSI hotplug operations a
separate context.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/libata-core.c |    9 +++++++++
 drivers/scsi/libata.h      |    1 +
 2 files changed, 10 insertions(+), 0 deletions(-)

84fc45de6b3fc32e8310a27dd54fa455a1038e9b
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 83fb9dd..aa1e0a1 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -69,6 +69,8 @@ static void ata_dev_xfermask(struct ata_
 static unsigned int ata_unique_id = 1;
 static struct workqueue_struct *ata_wq;
 
+struct workqueue_struct *ata_scsi_wq;
+
 int atapi_enabled = 1;
 module_param(atapi_enabled, int, 0444);
 MODULE_PARM_DESC(atapi_enabled, "Enable discovery of ATAPI devices (0=off, 1=on)");
@@ -5622,6 +5624,12 @@ static int __init ata_init(void)
 	if (!ata_wq)
 		return -ENOMEM;
 
+	ata_scsi_wq = create_singlethread_workqueue("ata_scsi");
+	if (!ata_scsi_wq) {
+		destroy_workqueue(ata_wq);
+		return -ENOMEM;
+	}
+
 	printk(KERN_DEBUG "libata version " DRV_VERSION " loaded.\n");
 	return 0;
 }
@@ -5629,6 +5637,7 @@ static int __init ata_init(void)
 static void __exit ata_exit(void)
 {
 	destroy_workqueue(ata_wq);
+	destroy_workqueue(ata_scsi_wq);
 }
 
 module_init(ata_init);
diff --git a/drivers/scsi/libata.h b/drivers/scsi/libata.h
index d46c552..d4bb2e4 100644
--- a/drivers/scsi/libata.h
+++ b/drivers/scsi/libata.h
@@ -39,6 +39,7 @@ struct ata_scsi_args {
 };
 
 /* libata-core.c */
+extern struct workqueue_struct *ata_scsi_wq;
 extern int atapi_enabled;
 extern int atapi_dmadir;
 extern int libata_fua;
-- 
1.3.2

[PATCH 10/12] libata-hp-prep: implement sata_phy_debounce()

[Tejun Heo]

With hotplug, PHY always needs to be debounced before a reset as any
reset might find new devices.  Extract PHY waiting code from
sata_phy_resume() and extend it to include SStatus debouncing.  Note
that sata_phy_debounce() is superset of what used to be done inside
sata_phy_resume().

Three default debounce timing parameters are defined to be used by
hot/boot plug.  As resume failure during probing will be properly
handled as errors, timeout doesn't have to be long as before.
probeinit() uses the same timeout to retain the original behavior.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/libata-core.c |  104 ++++++++++++++++++++++++++++++++++++++------
 include/linux/libata.h     |    6 +++
 2 files changed, 95 insertions(+), 15 deletions(-)

c9aae0f91110060a799f70706bd06ec0dab80cb0
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 009db45..9763395 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -61,6 +61,11 @@ #include <asm/byteorder.h>
 
 #include "libata.h"
 
+/* debounce timing parameters in msecs { interval, duration, timeout } */
+const unsigned long sata_deb_timing_boot[]		= {   5,  100, 2000 };
+const unsigned long sata_deb_timing_eh[]		= {  25,  500, 2000 };
+const unsigned long sata_deb_timing_before_fsrst[]	= { 100, 2000, 5000 };
+
 static unsigned int ata_dev_init_params(struct ata_device *dev,
 					u16 heads, u16 sectors);
 static unsigned int ata_dev_set_xfermode(struct ata_device *dev);
@@ -2427,10 +2432,81 @@ err_out:
 	DPRINTK("EXIT\n");
 }
 
-static int sata_phy_resume(struct ata_port *ap)
+/**
+ *	sata_phy_debounce - debounce SATA phy status
+ *	@ap: ATA port to debounce SATA phy status for
+ *	@params: timing parameters { interval, duratinon, timeout } in msec
+ *
+ *	Make sure SStatus of @ap reaches stable state, determined by
+ *	holding the same value where DET is not 1 for @duration polled
+ *	every @interval, before @timeout.  Timeout constraints the
+ *	beginning of the stable state.  Because, after hot unplugging,
+ *	DET gets stuck at 1 on some controllers, this functions waits
+ *	until timeout then returns 0 if DET is stable at 1.
+ *
+ *	LOCKING:
+ *	Kernel thread context (may sleep)
+ *
+ *	RETURNS:
+ *	0 on success, -errno on failure.
+ */
+int sata_phy_debounce(struct ata_port *ap, const unsigned long *params)
 {
-	unsigned long timeout = jiffies + (HZ * 5);
-	u32 scontrol, sstatus;
+	unsigned long interval_msec = params[0];
+	unsigned long duration = params[1] * HZ / 1000;
+	unsigned long timeout = jiffies + params[2] * HZ / 1000;
+	unsigned long last_jiffies;
+	u32 last, cur;
+	int rc;
+
+	if ((rc = sata_scr_read(ap, SCR_STATUS, &cur)))
+		return rc;
+	cur &= 0xf;
+
+	last = cur;
+	last_jiffies = jiffies;
+
+	while (1) {
+		msleep(interval_msec);
+		if ((rc = sata_scr_read(ap, SCR_STATUS, &cur)))
+			return rc;
+		cur &= 0xf;
+
+		/* DET stable? */
+		if (cur == last) {
+			if (cur == 1 && time_before(jiffies, timeout))
+				continue;
+			if (time_after(jiffies, last_jiffies + duration))
+				return 0;
+			continue;
+		}
+
+		/* unstable, start over */
+		last = cur;
+		last_jiffies = jiffies;
+
+		/* check timeout */
+		if (time_after(jiffies, timeout))
+			return -EBUSY;
+	}
+}
+
+/**
+ *	sata_phy_resume - resume SATA phy
+ *	@ap: ATA port to resume SATA phy for
+ *	@params: timing parameters { interval, duratinon, timeout } in msec
+ *
+ *	Resume SATA phy of @ap and debounce it.
+ *
+ *	LOCKING:
+ *	Kernel thread context (may sleep)
+ *
+ *	RETURNS:
+ *	0 on success, -errno on failure.
+ */
+int sata_phy_resume(struct ata_port *ap, const unsigned long *params)
+{
+	u32 scontrol;
 	int rc;
 
 	if ((rc = sata_scr_read(ap, SCR_CONTROL, &scontrol)))
@@ -2441,16 +2517,7 @@ static int sata_phy_resume(struct ata_po
 	if ((rc = sata_scr_write(ap, SCR_CONTROL, scontrol)))
 		return rc;
 
-	/* Wait for phy to become ready, if necessary. */
-	do {
-		msleep(200);
-		if ((rc = sata_scr_read(ap, SCR_STATUS, &sstatus)))
-			return rc;
-		if ((sstatus & 0xf) != 1)
-			return 0;
-	} while (time_before(jiffies, timeout));
-
-	return -EBUSY;
+	return sata_phy_debounce(ap, params);
 }
 
 /**
@@ -2468,8 +2535,10 @@ static int sata_phy_resume(struct ata_po
  */
 void ata_std_probeinit(struct ata_port *ap)
 {
+	static const unsigned long deb_timing[] = { 5, 100, 5000 };
+
 	/* resume link */
-	sata_phy_resume(ap);
+	sata_phy_resume(ap, deb_timing);
 
 	/* wait for device */
 	if (ata_port_online(ap))
@@ -2585,7 +2654,7 @@ int sata_std_hardreset(struct ata_port *
 	msleep(1);
 
 	/* bring phy back */
-	sata_phy_resume(ap);
+	sata_phy_resume(ap, sata_deb_timing_eh);
 
 	/* TODO: phy layer with polling, timeouts, etc. */
 	if (ata_port_offline(ap)) {
@@ -5717,6 +5786,9 @@ u32 ata_wait_register(void __iomem *reg,
  * Do not depend on ABI/API stability.
  */
 
+EXPORT_SYMBOL_GPL(sata_deb_timing_boot);
+EXPORT_SYMBOL_GPL(sata_deb_timing_eh);
+EXPORT_SYMBOL_GPL(sata_deb_timing_before_fsrst);
 EXPORT_SYMBOL_GPL(ata_std_bios_param);
 EXPORT_SYMBOL_GPL(ata_std_ports);
 EXPORT_SYMBOL_GPL(ata_device_add);
@@ -5756,6 +5828,8 @@ EXPORT_SYMBOL_GPL(ata_bmdma_error_handle
 EXPORT_SYMBOL_GPL(ata_bmdma_post_internal_cmd);
 EXPORT_SYMBOL_GPL(ata_port_probe);
 EXPORT_SYMBOL_GPL(sata_set_spd);
+EXPORT_SYMBOL_GPL(sata_phy_debounce);
+EXPORT_SYMBOL_GPL(sata_phy_resume);
 EXPORT_SYMBOL_GPL(sata_phy_reset);
 EXPORT_SYMBOL_GPL(__sata_phy_reset);
 EXPORT_SYMBOL_GPL(ata_bus_reset);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 54b2259..838b11a 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -605,11 +605,17 @@ struct ata_timing {
 
 #define FIT(v,vmin,vmax)	max_t(short,min_t(short,v,vmax),vmin)
 
+extern const unsigned long sata_deb_timing_boot[];
+extern const unsigned long sata_deb_timing_eh[];
+extern const unsigned long sata_deb_timing_before_fsrst[];
+
 extern void ata_port_probe(struct ata_port *);
 extern void __sata_phy_reset(struct ata_port *ap);
 extern void sata_phy_reset(struct ata_port *ap);
 extern void ata_bus_reset(struct ata_port *ap);
 extern int sata_set_spd(struct ata_port *ap);
+extern int sata_phy_debounce(struct ata_port *ap, const unsigned long *param);
+extern int sata_phy_resume(struct ata_port *ap, const unsigned long *param);
 extern int ata_drive_probe_reset(struct ata_port *ap,
 			ata_probeinit_fn_t probeinit,
 			ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
-- 
1.3.2

Re: [PATCH 10/12] libata-hp-prep: implement sata_phy_debounce()

[Jeff Garzik]

Tejun Heo wrote:
> With hotplug, PHY always needs to be debounced before a reset as any
> reset might find new devices.  Extract PHY waiting code from
> sata_phy_resume() and extend it to include SStatus debouncing.  Note
> that sata_phy_debounce() is superset of what used to be done inside
> sata_phy_resume().
> 
> Three default debounce timing parameters are defined to be used by
> hot/boot plug.  As resume failure during probing will be properly
> handled as errors, timeout doesn't have to be long as before.
> probeinit() uses the same timeout to retain the original behavior.
> 
> Signed-off-by: Tejun Heo <htejun@gmail.com>
> 
> ---
> 
>  drivers/scsi/libata-core.c |  104 ++++++++++++++++++++++++++++++++++++++------
>  include/linux/libata.h     |    6 +++
>  2 files changed, 95 insertions(+), 15 deletions(-)
> 
> c9aae0f91110060a799f70706bd06ec0dab80cb0
> diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
> index 009db45..9763395 100644
> --- a/drivers/scsi/libata-core.c
> +++ b/drivers/scsi/libata-core.c
> @@ -61,6 +61,11 @@ #include <asm/byteorder.h>
>  
>  #include "libata.h"
>  
> +/* debounce timing parameters in msecs { interval, duration, timeout } */
> +const unsigned long sata_deb_timing_boot[]		= {   5,  100, 2000 };
> +const unsigned long sata_deb_timing_eh[]		= {  25,  500, 2000 };
> +const unsigned long sata_deb_timing_before_fsrst[]	= { 100, 2000, 5000 };
> +
>  static unsigned int ata_dev_init_params(struct ata_device *dev,
>  					u16 heads, u16 sectors);
>  static unsigned int ata_dev_set_xfermode(struct ata_device *dev);
> @@ -2427,10 +2432,81 @@ err_out:
>  	DPRINTK("EXIT\n");
>  }
>  
> -static int sata_phy_resume(struct ata_port *ap)
> +/**
> + *	sata_phy_debounce - debounce SATA phy status
> + *	@ap: ATA port to debounce SATA phy status for
> + *	@params: timing parameters { interval, duratinon, timeout } in msec
> + *
> + *	Make sure SStatus of @ap reaches stable state, determined by
> + *	holding the same value where DET is not 1 for @duration polled
> + *	every @interval, before @timeout.  Timeout constraints the
> + *	beginning of the stable state.  Because, after hot unplugging,
> + *	DET gets stuck at 1 on some controllers, this functions waits
> + *	until timeout then returns 0 if DET is stable at 1.
> + *
> + *	LOCKING:
> + *	Kernel thread context (may sleep)
> + *
> + *	RETURNS:
> + *	0 on success, -errno on failure.
> + */
> +int sata_phy_debounce(struct ata_port *ap, const unsigned long *params)
>  {
> -	unsigned long timeout = jiffies + (HZ * 5);
> -	u32 scontrol, sstatus;
> +	unsigned long interval_msec = params[0];
> +	unsigned long duration = params[1] * HZ / 1000;
> +	unsigned long timeout = jiffies + params[2] * HZ / 1000;
> +	unsigned long last_jiffies;
> +	u32 last, cur;
> +	int rc;
> +
> +	if ((rc = sata_scr_read(ap, SCR_STATUS, &cur)))
> +		return rc;
> +	cur &= 0xf;
> +
> +	last = cur;
> +	last_jiffies = jiffies;
> +
> +	while (1) {
> +		msleep(interval_msec);
> +		if ((rc = sata_scr_read(ap, SCR_STATUS, &cur)))
> +			return rc;
> +		cur &= 0xf;
> +
> +		/* DET stable? */
> +		if (cur == last) {
> +			if (cur == 1 && time_before(jiffies, timeout))
> +				continue;
> +			if (time_after(jiffies, last_jiffies + duration))
> +				return 0;
> +			continue;
> +		}

NAK, changes behavior.  We want to preserve the old order of operations 
because some PHYs (sata_via and sata_mv come to mind) are a bit 
sensitive to being pounded immediately after wakeup.

	Jeff

Re: [PATCH 10/12] libata-hp-prep: implement sata_phy_debounce()

[Tejun Heo]

Jeff Garzik wrote:
> Tejun Heo wrote:
>> With hotplug, PHY always needs to be debounced before a reset as any
>> reset might find new devices.  Extract PHY waiting code from
>> sata_phy_resume() and extend it to include SStatus debouncing.  Note
>> that sata_phy_debounce() is superset of what used to be done inside
>> sata_phy_resume().
>>
>> Three default debounce timing parameters are defined to be used by
>> hot/boot plug.  As resume failure during probing will be properly
>> handled as errors, timeout doesn't have to be long as before.
>> probeinit() uses the same timeout to retain the original behavior.
>>
>> Signed-off-by: Tejun Heo <htejun@gmail.com>
>
> NAK, changes behavior.  We want to preserve the old order of operations 
> because some PHYs (sata_via and sata_mv come to mind) are a bit 
> sensitive to being pounded immediately after wakeup.

The following is what the original sata_phy_resume() did

1. read SControl
2. write SControl (wake)
3. msleep(200)
4. read SStatus
5. if condition not met, goto #3

The new code does...

1. read SControl
2. write SControl (wake)
3. read SStatus
4. msleep(interval_msec)
5. read SStatus
6. if condition not met, goto #4

How about putting msleep(200) before calling sata_phy_debounce() from 
sata_phy_resume().  This will add msleep(200) between #2 and #3 and the 
only difference left would be the duration of interval_msec in #4 which 
is 5ms during boot, 25ms during EH.  The wait is in the millisecs range 
and it's difficult to imagine the change would cause any problem.

-- 
tejun

Re: [PATCH 10/12] libata-hp-prep: implement sata_phy_debounce()

[Jeff Garzik]

Tejun Heo wrote:
> Jeff Garzik wrote:
>> Tejun Heo wrote:
>>> With hotplug, PHY always needs to be debounced before a reset as any
>>> reset might find new devices.  Extract PHY waiting code from
>>> sata_phy_resume() and extend it to include SStatus debouncing.  Note
>>> that sata_phy_debounce() is superset of what used to be done inside
>>> sata_phy_resume().
>>>
>>> Three default debounce timing parameters are defined to be used by
>>> hot/boot plug.  As resume failure during probing will be properly
>>> handled as errors, timeout doesn't have to be long as before.
>>> probeinit() uses the same timeout to retain the original behavior.
>>>
>>> Signed-off-by: Tejun Heo <htejun@gmail.com>
>>
>> NAK, changes behavior.  We want to preserve the old order of 
>> operations because some PHYs (sata_via and sata_mv come to mind) are a 
>> bit sensitive to being pounded immediately after wakeup.
> 
> The following is what the original sata_phy_resume() did
> 
> 1. read SControl
> 2. write SControl (wake)
> 3. msleep(200)
> 4. read SStatus
> 5. if condition not met, goto #3
> 
> The new code does...
> 
> 1. read SControl
> 2. write SControl (wake)
> 3. read SStatus
> 4. msleep(interval_msec)
> 5. read SStatus
> 6. if condition not met, goto #4
> 
> How about putting msleep(200) before calling sata_phy_debounce() from 
> sata_phy_resume().  This will add msleep(200) between #2 and #3 and the 
> only difference left would be the duration of interval_msec in #4 which 
> is 5ms during boot, 25ms during EH.  The wait is in the millisecs range 
> and it's difficult to imagine the change would cause any problem.

As long as the delay following #2 remains, I'm happy...

	Jeff

[PATCH 04/12] libata-hp-prep: update ata_scsi_find_dev() and friends

[Tejun Heo]

Separate out ata_find_dev() and __ata_scsi_find_dev() from
ata_scsi_find_dev().  ata_find_dev() checks ATA_FLAG_SLAVE_POSS for
id==1 case, so all three functions return NULL if id==1 is specified
for !SLAVE_POSS port.  These will be used by later hotplug
implementation.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/libata-scsi.c |   40 +++++++++++++++++++++++++---------------
 1 files changed, 25 insertions(+), 15 deletions(-)

113b8fe60b97a6ce664d6098f23b56b75247de87
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 9e5cb9f..9adc5c1 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -52,8 +52,12 @@ #include "libata.h"
 #define SECTOR_SIZE	512
 
 typedef unsigned int (*ata_xlat_func_t)(struct ata_queued_cmd *qc, const u8 *scsicmd);
-static struct ata_device *
-ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device *scsidev);
+
+static struct ata_device * __ata_scsi_find_dev(struct ata_port *ap,
+					const struct scsi_device *scsidev);
+static struct ata_device * ata_scsi_find_dev(struct ata_port *ap,
+					    const struct scsi_device *scsidev);
+
 
 #define RW_RECOVERY_MPAGE 0x1
 #define RW_RECOVERY_MPAGE_LEN 12
@@ -2308,6 +2312,23 @@ static unsigned int atapi_xlat(struct at
 	return 0;
 }
 
+static struct ata_device * ata_find_dev(struct ata_port *ap, int id)
+{
+	if (likely(id == 0 || (id == 1 && ap->flags & ATA_FLAG_SLAVE_POSS)))
+		return &ap->device[id];
+	return NULL;
+}
+
+static struct ata_device * __ata_scsi_find_dev(struct ata_port *ap,
+					const struct scsi_device *scsidev)
+{
+	/* skip commands not addressed to targets we simulate */
+	if (unlikely(scsidev->channel || scsidev->lun))
+		return NULL;
+
+	return ata_find_dev(ap, scsidev->id);
+}
+
 /**
  *	ata_scsi_find_dev - lookup ata_device from scsi_cmnd
  *	@ap: ATA port to which the device is attached
@@ -2324,23 +2345,12 @@ static unsigned int atapi_xlat(struct at
  *	RETURNS:
  *	Associated ATA device, or %NULL if not found.
  */
-
 static struct ata_device *
 ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device *scsidev)
 {
-	struct ata_device *dev;
-
-	/* skip commands not addressed to targets we simulate */
-	if (likely(scsidev->id < ATA_MAX_DEVICES))
-		dev = &ap->device[scsidev->id];
-	else
-		return NULL;
-
-	if (unlikely((scsidev->channel != 0) ||
-		     (scsidev->lun != 0)))
-		return NULL;
+	struct ata_device *dev = __ata_scsi_find_dev(ap, scsidev);
 
-	if (unlikely(!ata_dev_enabled(dev)))
+	if (unlikely(!dev || !ata_dev_enabled(dev)))
 		return NULL;
 
 	if (!atapi_enabled || (ap->flags & ATA_FLAG_NO_ATAPI)) {
-- 
1.3.2

Re: [PATCH 04/12] libata-hp-prep: update ata_scsi_find_dev() and friends

[zhao, forrest]

On Mon, 2006-05-29 at 15:25 +0900, Tejun Heo wrote:
> 113b8fe60b97a6ce664d6098f23b56b75247de87
> diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
> index 9e5cb9f..9adc5c1 100644
> --- a/drivers/scsi/libata-scsi.c
> +++ b/drivers/scsi/libata-scsi.c
> @@ -52,8 +52,12 @@ #include "libata.h"
>  #define SECTOR_SIZE	512
>  
>  typedef unsigned int (*ata_xlat_func_t)(struct ata_queued_cmd *qc, const u8 *scsicmd);
> -static struct ata_device *
> -ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device *scsidev);
> +
> +static struct ata_device * __ata_scsi_find_dev(struct ata_port *ap,
> +					const struct scsi_device *scsidev);
> +static struct ata_device * ata_scsi_find_dev(struct ata_port *ap,
> +					    const struct scsi_device *scsidev);
> +
>  
>  #define RW_RECOVERY_MPAGE 0x1
>  #define RW_RECOVERY_MPAGE_LEN 12
> @@ -2308,6 +2312,23 @@ static unsigned int atapi_xlat(struct at
>  	return 0;
>  }
>  
> +static struct ata_device * ata_find_dev(struct ata_port *ap, int id)
> +{
> +	if (likely(id == 0 || (id == 1 && ap->flags & ATA_FLAG_SLAVE_POSS)))
> +		return &ap->device[id];
> +	return NULL;
> +}
> +

>From my understanding, the definition of function ata_find_dev() should
be in libata-core.c instead of libata-scsi.c. Does it make sense to you?

Thanks,
Forrest

Re: [PATCH 04/12] libata-hp-prep: update ata_scsi_find_dev() and friends

[Tejun Heo]

>> +static struct ata_device * ata_find_dev(struct ata_port *ap, int id)
>> +{
>> +	if (likely(id == 0 || (id == 1 && ap->flags & ATA_FLAG_SLAVE_POSS)))
>> +		return &ap->device[id];
>> +	return NULL;
>> +}
>> +
> 
>>From my understanding, the definition of function ata_find_dev() should
> be in libata-core.c instead of libata-scsi.c. Does it make sense to you?

Could be.  However, as it's currently used only inside libata-scsi.c, I
think we can leave it as static function for the time being.

-- 
tejun

Re: [PATCH 04/12] libata-hp-prep: update ata_scsi_find_dev() and friends

[Jeff Garzik]

zhao, forrest wrote:
> On Mon, 2006-05-29 at 15:25 +0900, Tejun Heo wrote:
>> 113b8fe60b97a6ce664d6098f23b56b75247de87
>> diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
>> index 9e5cb9f..9adc5c1 100644
>> --- a/drivers/scsi/libata-scsi.c
>> +++ b/drivers/scsi/libata-scsi.c
>> @@ -52,8 +52,12 @@ #include "libata.h"
>>  #define SECTOR_SIZE	512
>>  
>>  typedef unsigned int (*ata_xlat_func_t)(struct ata_queued_cmd *qc, const u8 *scsicmd);
>> -static struct ata_device *
>> -ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device *scsidev);
>> +
>> +static struct ata_device * __ata_scsi_find_dev(struct ata_port *ap,
>> +					const struct scsi_device *scsidev);
>> +static struct ata_device * ata_scsi_find_dev(struct ata_port *ap,
>> +					    const struct scsi_device *scsidev);
>> +
>>  
>>  #define RW_RECOVERY_MPAGE 0x1
>>  #define RW_RECOVERY_MPAGE_LEN 12
>> @@ -2308,6 +2312,23 @@ static unsigned int atapi_xlat(struct at
>>  	return 0;
>>  }
>>  
>> +static struct ata_device * ata_find_dev(struct ata_port *ap, int id)
>> +{
>> +	if (likely(id == 0 || (id == 1 && ap->flags & ATA_FLAG_SLAVE_POSS)))
>> +		return &ap->device[id];
>> +	return NULL;
>> +}
>> +
> 
>>From my understanding, the definition of function ata_find_dev() should
> be in libata-core.c instead of libata-scsi.c. Does it make sense to you?

You are correct from a modularity standpoint, but doing so will 
eliminate the possibility of the compiler noticing that this function -- 
a fast path function -- is small enough to inline.  That would 
completely eliminate the function call overhead.

	Jeff

Re: [PATCH 04/12] libata-hp-prep: update ata_scsi_find_dev() and friends

[Jeff Garzik]

Tejun Heo wrote:
> +static struct ata_device * ata_find_dev(struct ata_port *ap, int id)
> +{
> +	if (likely(id == 0 || (id == 1 && ap->flags & ATA_FLAG_SLAVE_POSS)))
> +		return &ap->device[id];
> +	return NULL;

>  static struct ata_device *
>  ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device *scsidev)
>  {
> -	struct ata_device *dev;
> -
> -	/* skip commands not addressed to targets we simulate */
> -	if (likely(scsidev->id < ATA_MAX_DEVICES))
> -		dev = &ap->device[scsidev->id];
> -	else
> -		return NULL;


You replace a '<' test with a more complex test, which must then be 
modified when we start supporting Port Multipliers.

It is more simple, and easier, to keep the 'id < ATA_MAX_DEVICES' test 
AFAICS.

	Jeff

Re: [PATCH 04/12] libata-hp-prep: update ata_scsi_find_dev() and friends

[Tejun Heo]

Jeff Garzik wrote:
> Tejun Heo wrote:
>> +static struct ata_device * ata_find_dev(struct ata_port *ap, int id)
>> +{
>> +    if (likely(id == 0 || (id == 1 && ap->flags & ATA_FLAG_SLAVE_POSS)))
>> +        return &ap->device[id];
>> +    return NULL;
> 
>>  static struct ata_device *
>>  ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device 
>> *scsidev)
>>  {
>> -    struct ata_device *dev;
>> -
>> -    /* skip commands not addressed to targets we simulate */
>> -    if (likely(scsidev->id < ATA_MAX_DEVICES))
>> -        dev = &ap->device[scsidev->id];
>> -    else
>> -        return NULL;
> 
> 
> You replace a '<' test with a more complex test, which must then be 
> modified when we start supporting Port Multipliers.
> 
> It is more simple, and easier, to keep the 'id < ATA_MAX_DEVICES' test 
> AFAICS.

The change is to catch user warm plug request for impossible devices.  I 
think it's worth to change it two times as it makes user visible 
interface consistent.

-- 
tejun

Re: [PATCH 04/12] libata-hp-prep: update ata_scsi_find_dev() and friends

[Jeff Garzik]

Tejun Heo wrote:
> Jeff Garzik wrote:
>> Tejun Heo wrote:
>>> +static struct ata_device * ata_find_dev(struct ata_port *ap, int id)
>>> +{
>>> +    if (likely(id == 0 || (id == 1 && ap->flags & 
>>> ATA_FLAG_SLAVE_POSS)))
>>> +        return &ap->device[id];
>>> +    return NULL;
>>
>>>  static struct ata_device *
>>>  ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device 
>>> *scsidev)
>>>  {
>>> -    struct ata_device *dev;
>>> -
>>> -    /* skip commands not addressed to targets we simulate */
>>> -    if (likely(scsidev->id < ATA_MAX_DEVICES))
>>> -        dev = &ap->device[scsidev->id];
>>> -    else
>>> -        return NULL;
>>
>>
>> You replace a '<' test with a more complex test, which must then be 
>> modified when we start supporting Port Multipliers.
>>
>> It is more simple, and easier, to keep the 'id < ATA_MAX_DEVICES' test 
>> AFAICS.
> 
> The change is to catch user warm plug request for impossible devices.  I 
> think it's worth to change it two times as it makes user visible 
> interface consistent.

Warm plug isn't a fast path, but this is...  I would rather filter out 
bad IDs elsewhere; and the code itself will catch bad IDs anyway, 
eventually.

	Jeff

Re: [PATCH 04/12] libata-hp-prep: update ata_scsi_find_dev() and friends

[Tejun Heo]

Jeff Garzik wrote:
> Tejun Heo wrote:
>> Jeff Garzik wrote:
>>> Tejun Heo wrote:
>>>> +static struct ata_device * ata_find_dev(struct ata_port *ap, int id)
>>>> +{
>>>> +    if (likely(id == 0 || (id == 1 && ap->flags & 
>>>> ATA_FLAG_SLAVE_POSS)))
>>>> +        return &ap->device[id];
>>>> +    return NULL;
>>>
>>>>  static struct ata_device *
>>>>  ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device 
>>>> *scsidev)
>>>>  {
>>>> -    struct ata_device *dev;
>>>> -
>>>> -    /* skip commands not addressed to targets we simulate */
>>>> -    if (likely(scsidev->id < ATA_MAX_DEVICES))
>>>> -        dev = &ap->device[scsidev->id];
>>>> -    else
>>>> -        return NULL;
>>>
>>>
>>> You replace a '<' test with a more complex test, which must then be 
>>> modified when we start supporting Port Multipliers.
>>>
>>> It is more simple, and easier, to keep the 'id < ATA_MAX_DEVICES' 
>>> test AFAICS.
>>
>> The change is to catch user warm plug request for impossible devices.  
>> I think it's worth to change it two times as it makes user visible 
>> interface consistent.
> 
> Warm plug isn't a fast path, but this is...  I would rather filter out 
> bad IDs elsewhere; and the code itself will catch bad IDs anyway, 
> eventually.

Okay, I'll drop the change.

-- 
tejun

[PATCH 12/12] libata-hp-prep: implement followup softreset handling

[Tejun Heo]

In some cases, hardreset must be followed by SRST.

* some controllers can't classify with hardreset
* some controllers can't wait for !BSY after hardreset (LLDD should
  explicitly request followup softreset by returning -EAGAIN)
* (later) PM needs SRST w/ PMP==15 to operate after hardreset

To handle above cases, this patch implements follow-up softreset.
After a hardreset, ata_eh_reset() checks whether any of above
conditions are met and do a follow-up softreset if necessary.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/libata-eh.c |   58 +++++++++++++++++++++++++++++++++++++++++-----
 1 files changed, 52 insertions(+), 6 deletions(-)

a92b5a9913a41dbf5ef816da38b015a4319b54ea
diff --git a/drivers/scsi/libata-eh.c b/drivers/scsi/libata-eh.c
index ab2c640..4189bb4 100644
--- a/drivers/scsi/libata-eh.c
+++ b/drivers/scsi/libata-eh.c
@@ -1280,16 +1280,28 @@ static void ata_eh_report(struct ata_por
 	}
 }
 
-static int ata_eh_reset(struct ata_port *ap,
+static int ata_eh_followup_srst_needed(int rc, int classify,
+				       const unsigned int *classes)
+{
+	if (rc == -EAGAIN)
+		return 1;
+	if (rc != 0)
+		return 0;
+	if (classify && classes[0] == ATA_DEV_UNKNOWN)
+		return 1;
+	return 0;
+}
+
+static int ata_eh_reset(struct ata_port *ap, int classify,
 			ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
 			ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
 {
 	struct ata_eh_context *ehc = &ap->eh_context;
-	unsigned int classes[ATA_MAX_DEVICES];
+	unsigned int *classes = ehc->classes;
 	int tries = ATA_EH_RESET_TRIES;
 	unsigned int action;
 	ata_reset_fn_t reset;
-	int i, rc;
+	int i, did_followup_srst, rc;
 
 	/* Determine which reset to use and record in ehc->i.action.
 	 * prereset() may examine and modify it.
@@ -1343,10 +1355,44 @@ static int ata_eh_reset(struct ata_port 
 
 	rc = ata_do_reset(ap, reset, classes);
 
+	did_followup_srst = 0;
+	if (reset == hardreset &&
+	    ata_eh_followup_srst_needed(rc, classify, classes)) {
+		/* okay, let's do follow-up softreset */
+		did_followup_srst = 1;
+		reset = softreset;
+
+		if (!reset) {
+			ata_port_printk(ap, KERN_ERR,
+					"follow-up softreset required "
+					"but no softreset avaliable\n");
+			return -EINVAL;
+		}
+
+		ata_eh_about_to_do(ap, ATA_EH_RESET_MASK);
+		rc = ata_do_reset(ap, reset, classes);
+
+		if (rc == 0 && classify &&
+		    classes[0] == ATA_DEV_UNKNOWN) {
+			ata_port_printk(ap, KERN_ERR,
+					"classification failed\n");
+			return -EINVAL;
+		}
+	}
+
 	if (rc && --tries) {
+		const char *type;
+
+		if (reset == softreset) {
+			if (did_followup_srst)
+				type = "follow-up soft";
+			else
+				type = "soft";
+		} else
+			type = "hard";
+
 		ata_port_printk(ap, KERN_WARNING,
-				"%sreset failed, retrying in 5 secs\n",
-				reset == softreset ? "soft" : "hard");
+				"%sreset failed, retrying in 5 secs\n", type);
 		ssleep(5);
 
 		if (reset == hardreset)
@@ -1470,7 +1516,7 @@ static int ata_eh_recover(struct ata_por
 	if (ehc->i.action & ATA_EH_RESET_MASK) {
 		ata_eh_freeze_port(ap);
 
-		rc = ata_eh_reset(ap, prereset, softreset, hardreset,
+		rc = ata_eh_reset(ap, 0, prereset, softreset, hardreset,
 				  postreset);
 		if (rc) {
 			ata_port_printk(ap, KERN_ERR,
-- 
1.3.2

Re: [PATCH 12/12] libata-hp-prep: implement followup softreset handling

[Jeff Garzik]

Tejun Heo wrote:
> In some cases, hardreset must be followed by SRST.
> 
> * some controllers can't classify with hardreset
> * some controllers can't wait for !BSY after hardreset (LLDD should
>   explicitly request followup softreset by returning -EAGAIN)
> * (later) PM needs SRST w/ PMP==15 to operate after hardreset
> 
> To handle above cases, this patch implements follow-up softreset.
> After a hardreset, ata_eh_reset() checks whether any of above
> conditions are met and do a follow-up softreset if necessary.
> 
> Signed-off-by: Tejun Heo <htejun@gmail.com>

ACK

[PATCH 11/12] libata-hp-prep: add prereset() method and implement ata_std_prereset()

[Tejun Heo]

With hotplug, every reset might be a probing reset and thus something
similar to probe_init() is needed.  prereset() method is called before
a series of resets to a port and is the counterpart of postreset().
prereset() can tell EH to use different type of reset or skip reset by
modifying ehc->i.action.

This patch also implements ata_std_prereset().  Most controllers
should be able to use this function directly or with some wrapping.
After hotplug, different controllers need different actions to resume
the PHY and detect the newly attached device.  Controllers can be
categorized as follows.

* Controllers which can wait for the first FIS34 after hotplug.  Note
  that if the waiting is implemented by polling TF status, there needs
  to be a way to set BSY on PHY status change.  It can be implemented
  by hardware or with the help of the driver.

* Controllers which can wait for the first FIS34 after sending
  COMRESET.  These controllers need to issue COMRESET to wait for the
  first FIS.  Note that the received FIS34 could be the first FIS34
  after POR (power-on-reset) or FIS34 in response to the COMRESET.
  Some controllers use COMRESET as TF status synchronization point and
  clear TF automatically (sata_sil).

* Controllers which cannot wait for the first FIS34 reliably.  Blindly
  issuing SRST to spinning-up device often results in command issue
  failure or timeout, causing extended delay.  For these controllers,
  ata_std_prereset() explicitly waits ATA_SPINUP_WAIT (currently 8s)
  to give newly attached device time to spin up, then issues reset.
  Note that failing to getting ready in ATA_SPINUP_WAIT is not
  critical.  libata will retry.  So, the timeout needs to be long
  enough to spin up most devices.

LLDDs can tell ata_std_prereset() which of above action is needed with
ATA_FLAG_HRST_TO_RESUME and ATA_FLAG_CANT_WAIT_FIS34 flags.  These
flags are PHY-specific property and will be moved to ata_link later.

While at it, this patch unifies function typedef's such that they all
have named arguments.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/ahci.c         |    3 +-
 drivers/scsi/libata-bmdma.c |   11 ++++--
 drivers/scsi/libata-core.c  |   85 +++++++++++++++++++++++++++++++++++++++++++
 drivers/scsi/libata-eh.c    |   60 ++++++++++++++++++++++++++----
 drivers/scsi/sata_sil24.c   |    3 +-
 include/linux/libata.h      |   24 +++++++++---
 6 files changed, 165 insertions(+), 21 deletions(-)

232f49110f635dc8d95966eaa556d37a87cf7992
diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index 45fd71d..8493b02 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -1026,7 +1026,8 @@ static void ahci_error_handler(struct at
 	}
 
 	/* perform recovery */
-	ata_do_eh(ap, ahci_softreset, ahci_hardreset, ahci_postreset);
+	ata_do_eh(ap, ata_std_prereset, ahci_softreset, ahci_hardreset,
+		  ahci_postreset);
 }
 
 static void ahci_post_internal_cmd(struct ata_queued_cmd *qc)
diff --git a/drivers/scsi/libata-bmdma.c b/drivers/scsi/libata-bmdma.c
index 6d30d2c..4bc0537 100644
--- a/drivers/scsi/libata-bmdma.c
+++ b/drivers/scsi/libata-bmdma.c
@@ -695,6 +695,7 @@ void ata_bmdma_thaw(struct ata_port *ap)
 /**
  *	ata_bmdma_drive_eh - Perform EH with given methods for BMDMA controller
  *	@ap: port to handle error for
+ *	@prereset: prereset method (can be NULL)
  *	@softreset: softreset method (can be NULL)
  *	@hardreset: hardreset method (can be NULL)
  *	@postreset: postreset method (can be NULL)
@@ -710,8 +711,9 @@ void ata_bmdma_thaw(struct ata_port *ap)
  *	LOCKING:
  *	Kernel thread context (may sleep)
  */
-void ata_bmdma_drive_eh(struct ata_port *ap, ata_reset_fn_t softreset,
-			ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
+void ata_bmdma_drive_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
+			ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
+			ata_postreset_fn_t postreset)
 {
 	struct ata_host_set *host_set = ap->host_set;
 	struct ata_eh_context *ehc = &ap->eh_context;
@@ -759,7 +761,7 @@ void ata_bmdma_drive_eh(struct ata_port 
 		ata_eh_thaw_port(ap);
 
 	/* PIO and DMA engines have been stopped, perform recovery */
-	ata_do_eh(ap, softreset, hardreset, postreset);
+	ata_do_eh(ap, prereset, softreset, hardreset, postreset);
 }
 
 /**
@@ -779,7 +781,8 @@ void ata_bmdma_error_handler(struct ata_
 	if (sata_scr_valid(ap))
 		hardreset = sata_std_hardreset;
 
-	ata_bmdma_drive_eh(ap, ata_std_softreset, hardreset, ata_std_postreset);
+	ata_bmdma_drive_eh(ap, ata_std_prereset, ata_std_softreset, hardreset,
+			   ata_std_postreset);
 }
 
 /**
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 9763395..bbdc1ed 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2520,6 +2520,90 @@ int sata_phy_resume(struct ata_port *ap,
 	return sata_phy_debounce(ap, params);
 }
 
+static void ata_wait_spinup(struct ata_port *ap)
+{
+	struct ata_eh_context *ehc = &ap->eh_context;
+	unsigned long end, secs;
+	int rc;
+
+	/* first, debounce phy if SATA */
+	if (ap->cbl == ATA_CBL_SATA) {
+		rc = sata_phy_debounce(ap, sata_deb_timing_eh);
+
+		/* if debounced successfully and offline, no need to wait */
+		if (rc == 0 && ata_port_offline(ap))
+			return;
+	}
+
+	/* okay, let's give the drive time to spin up */
+	end = ehc->i.hotplug_timestamp + ATA_SPINUP_WAIT * HZ / 1000;
+	secs = ((end - jiffies) + HZ - 1) / HZ;
+
+	if (time_after(jiffies, end))
+		return;
+
+	if (secs > 5)
+		ata_port_printk(ap, KERN_INFO, "waiting for device to spin up "
+				"(%lu secs)\n", secs);
+
+	schedule_timeout_uninterruptible(end - jiffies);
+}
+
+/**
+ *	ata_std_prereset - prepare for reset
+ *	@ap: ATA port to be reset
+ *
+ *	@ap is about to be reset.  Initialize it.
+ *
+ *	LOCKING:
+ *	Kernel thread context (may sleep)
+ *
+ *	RETURNS:
+ *	0 on success, -errno otherwise.
+ */
+int ata_std_prereset(struct ata_port *ap)
+{
+	struct ata_eh_context *ehc = &ap->eh_context;
+	const unsigned long *timing;
+	int rc;
+
+	/* hotplug? */
+	if (ehc->i.flags & ATA_EHI_HOTPLUGGED) {
+		if (ap->flags & ATA_FLAG_HRST_TO_RESUME)
+			ehc->i.action |= ATA_EH_HARDRESET;
+		if (ap->flags & ATA_FLAG_SKIP_D2H_BSY)
+			ata_wait_spinup(ap);
+	}
+
+	/* if we're about to do hardreset, nothing more to do */
+	if (ehc->i.action & ATA_EH_HARDRESET)
+		return 0;
+
+	/* if SATA, resume phy */
+	if (ap->cbl == ATA_CBL_SATA) {
+		if (ap->flags & ATA_FLAG_LOADING)
+			timing = sata_deb_timing_boot;
+		else
+			timing = sata_deb_timing_eh;
+
+		rc = sata_phy_resume(ap, timing);
+		if (rc) {
+			/* phy resume failed */
+			ata_port_printk(ap, KERN_WARNING, "failed to resume "
+					"link for reset (errno=%d)\n", rc);
+			return rc;
+		}
+	}
+
+	/* Wait for !BSY if the controller can wait for the first D2H
+	 * Reg FIS and we don't know that no device is attached.
+	 */
+	if (!(ap->flags & ATA_FLAG_SKIP_D2H_BSY) && !ata_port_offline(ap))
+		ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT);
+
+	return 0;
+}
+
 /**
  *	ata_std_probeinit - initialize probing
  *	@ap: port to be probed
@@ -5834,6 +5918,7 @@ EXPORT_SYMBOL_GPL(sata_phy_reset);
 EXPORT_SYMBOL_GPL(__sata_phy_reset);
 EXPORT_SYMBOL_GPL(ata_bus_reset);
 EXPORT_SYMBOL_GPL(ata_std_probeinit);
+EXPORT_SYMBOL_GPL(ata_std_prereset);
 EXPORT_SYMBOL_GPL(ata_std_softreset);
 EXPORT_SYMBOL_GPL(sata_std_hardreset);
 EXPORT_SYMBOL_GPL(ata_std_postreset);
diff --git a/drivers/scsi/libata-eh.c b/drivers/scsi/libata-eh.c
index b88f492..ab2c640 100644
--- a/drivers/scsi/libata-eh.c
+++ b/drivers/scsi/libata-eh.c
@@ -1280,20 +1280,58 @@ static void ata_eh_report(struct ata_por
 	}
 }
 
-static int ata_eh_reset(struct ata_port *ap, ata_reset_fn_t softreset,
+static int ata_eh_reset(struct ata_port *ap,
+			ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
 			ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
 {
 	struct ata_eh_context *ehc = &ap->eh_context;
 	unsigned int classes[ATA_MAX_DEVICES];
 	int tries = ATA_EH_RESET_TRIES;
+	unsigned int action;
 	ata_reset_fn_t reset;
 	int i, rc;
 
+	/* Determine which reset to use and record in ehc->i.action.
+	 * prereset() may examine and modify it.
+	 */
+	action = ehc->i.action;
+	ehc->i.action &= ~ATA_EH_RESET_MASK;
 	if (softreset && (!hardreset || (!sata_set_spd_needed(ap) &&
-					 !(ehc->i.action & ATA_EH_HARDRESET))))
-		reset = softreset;
+					 !(action & ATA_EH_HARDRESET))))
+		ehc->i.action |= ATA_EH_SOFTRESET;
 	else
+		ehc->i.action |= ATA_EH_HARDRESET;
+
+	if (prereset) {
+		rc = prereset(ap);
+		if (rc) {
+			ata_port_printk(ap, KERN_ERR,
+					"prereset failed (errno=%d)\n", rc);
+			return rc;
+		}
+	}
+
+	/* prereset() might have modified ehc->i.action */
+	if (ehc->i.action & ATA_EH_HARDRESET)
 		reset = hardreset;
+	else if (ehc->i.action & ATA_EH_SOFTRESET)
+		reset = softreset;
+	else {
+		/* prereset told us not to reset, bang classes and return */
+		for (i = 0; i < ATA_MAX_DEVICES; i++)
+			classes[i] = ATA_DEV_NONE;
+		return 0;
+	}
+
+	/* did prereset() screw up?  if so, fix up to avoid oopsing */
+	if (!reset) {
+		ata_port_printk(ap, KERN_ERR, "BUG: prereset() requested "
+				"invalid reset type\n");
+		if (softreset)
+			reset = softreset;
+		else
+			reset = hardreset;
+	}
 
  retry:
 	ata_port_printk(ap, KERN_INFO, "%s resetting port\n",
@@ -1386,6 +1424,7 @@ static int ata_port_nr_enabled(struct at
 /**
  *	ata_eh_recover - recover host port after error
  *	@ap: host port to recover
+ *	@prereset: prereset method (can be NULL)
  *	@softreset: softreset method (can be NULL)
  *	@hardreset: hardreset method (can be NULL)
  *	@postreset: postreset method (can be NULL)
@@ -1402,8 +1441,8 @@ static int ata_port_nr_enabled(struct at
  *	RETURNS:
  *	0 on success, -errno on failure.
  */
-static int ata_eh_recover(struct ata_port *ap, ata_reset_fn_t softreset,
-			  ata_reset_fn_t hardreset,
+static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
+			  ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
 			  ata_postreset_fn_t postreset)
 {
 	struct ata_eh_context *ehc = &ap->eh_context;
@@ -1431,7 +1470,8 @@ static int ata_eh_recover(struct ata_por
 	if (ehc->i.action & ATA_EH_RESET_MASK) {
 		ata_eh_freeze_port(ap);
 
-		rc = ata_eh_reset(ap, softreset, hardreset, postreset);
+		rc = ata_eh_reset(ap, prereset, softreset, hardreset,
+				  postreset);
 		if (rc) {
 			ata_port_printk(ap, KERN_ERR,
 					"reset failed, giving up\n");
@@ -1548,6 +1588,7 @@ static void ata_eh_finish(struct ata_por
 /**
  *	ata_do_eh - do standard error handling
  *	@ap: host port to handle error for
+ *	@prereset: prereset method (can be NULL)
  *	@softreset: softreset method (can be NULL)
  *	@hardreset: hardreset method (can be NULL)
  *	@postreset: postreset method (can be NULL)
@@ -1557,11 +1598,12 @@ static void ata_eh_finish(struct ata_por
  *	LOCKING:
  *	Kernel thread context (may sleep).
  */
-void ata_do_eh(struct ata_port *ap, ata_reset_fn_t softreset,
-	       ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
+void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
+	       ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
+	       ata_postreset_fn_t postreset)
 {
 	ata_eh_autopsy(ap);
 	ata_eh_report(ap);
-	ata_eh_recover(ap, softreset, hardreset, postreset);
+	ata_eh_recover(ap, prereset, softreset, hardreset, postreset);
 	ata_eh_finish(ap);
 }
diff --git a/drivers/scsi/sata_sil24.c b/drivers/scsi/sata_sil24.c
index 4c76f05..26d7c54 100644
--- a/drivers/scsi/sata_sil24.c
+++ b/drivers/scsi/sata_sil24.c
@@ -912,7 +912,8 @@ static void sil24_error_handler(struct a
 	}
 
 	/* perform recovery */
-	ata_do_eh(ap, sil24_softreset, sil24_hardreset, ata_std_postreset);
+	ata_do_eh(ap, ata_std_prereset, sil24_softreset, sil24_hardreset,
+		  ata_std_postreset);
 }
 
 static void sil24_post_internal_cmd(struct ata_queued_cmd *qc)
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 838b11a..8822340 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -261,6 +261,15 @@ enum {
 	ATA_PROBE_MAX_TRIES	= 3,
 	ATA_EH_RESET_TRIES	= 3,
 	ATA_EH_DEV_TRIES	= 3,
+
+	/* Drive spinup time (time from power-on to the first FIS34)
+	 * in msecs - 8s currently.  Failing to get ready in this time
+	 * isn't critical.  It will result in reset failure for
+	 * controllers which can't wait for the first FIS34.  libata
+	 * will retry, so it just has to be long enough to spin up
+	 * most devices.
+	 */
+	ATA_SPINUP_WAIT		= 8000,
 };
 
 enum hsm_task_states {
@@ -293,9 +302,10 @@ struct ata_queued_cmd;
 
 /* typedefs */
 typedef void (*ata_qc_cb_t) (struct ata_queued_cmd *qc);
-typedef void (*ata_probeinit_fn_t)(struct ata_port *);
-typedef int (*ata_reset_fn_t)(struct ata_port *, unsigned int *);
-typedef void (*ata_postreset_fn_t)(struct ata_port *ap, unsigned int *);
+typedef void (*ata_probeinit_fn_t)(struct ata_port *ap);
+typedef int (*ata_prereset_fn_t)(struct ata_port *ap);
+typedef int (*ata_reset_fn_t)(struct ata_port *ap, unsigned int *classes);
+typedef void (*ata_postreset_fn_t)(struct ata_port *ap, unsigned int *classes);
 
 struct ata_ioports {
 	unsigned long		cmd_addr;
@@ -621,6 +631,7 @@ extern int ata_drive_probe_reset(struct 
 			ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
 			ata_postreset_fn_t postreset, unsigned int *classes);
 extern void ata_std_probeinit(struct ata_port *ap);
+extern int ata_std_prereset(struct ata_port *ap);
 extern int ata_std_softreset(struct ata_port *ap, unsigned int *classes);
 extern int sata_std_hardreset(struct ata_port *ap, unsigned int *class);
 extern void ata_std_postreset(struct ata_port *ap, unsigned int *classes);
@@ -704,7 +715,7 @@ extern u8   ata_bmdma_status(struct ata_
 extern void ata_bmdma_irq_clear(struct ata_port *ap);
 extern void ata_bmdma_freeze(struct ata_port *ap);
 extern void ata_bmdma_thaw(struct ata_port *ap);
-extern void ata_bmdma_drive_eh(struct ata_port *ap,
+extern void ata_bmdma_drive_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
 			       ata_reset_fn_t softreset,
 			       ata_reset_fn_t hardreset,
 			       ata_postreset_fn_t postreset);
@@ -782,8 +793,9 @@ extern void ata_eh_thaw_port(struct ata_
 extern void ata_eh_qc_complete(struct ata_queued_cmd *qc);
 extern void ata_eh_qc_retry(struct ata_queued_cmd *qc);
 
-extern void ata_do_eh(struct ata_port *ap, ata_reset_fn_t softreset,
-		      ata_reset_fn_t hardreset, ata_postreset_fn_t postreset);
+extern void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
+		      ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
+		      ata_postreset_fn_t postreset);
 
 /*
  * printk helpers
-- 
1.3.2

Re: [PATCH 11/12] (updated) libata-hp-prep: add prereset() method and implement ata_std_prereset()

[Tejun Heo]

With hotplug, every reset might be a probing reset and thus something
similar to probe_init() is needed.  prereset() method is called before
a series of resets to a port and is the counterpart of postreset().
prereset() can tell EH to use different type of reset or skip reset by
modifying ehc->i.action.

This patch also implements ata_std_prereset().  Most controllers
should be able to use this function directly or with some wrapping.
After hotplug, different controllers need different actions to resume
the PHY and detect the newly attached device.  Controllers can be
categorized as follows.

* Controllers which can wait for the first FIS34 after hotplug.  Note
  that if the waiting is implemented by polling TF status, there needs
  to be a way to set BSY on PHY status change.  It can be implemented
  by hardware or with the help of the driver.

* Controllers which can wait for the first FIS34 after sending
  COMRESET.  These controllers need to issue COMRESET to wait for the
  first FIS.  Note that the received FIS34 could be the first FIS34
  after POR (power-on-reset) or FIS34 in response to the COMRESET.
  Some controllers use COMRESET as TF status synchronization point and
  clear TF automatically (sata_sil).

* Controllers which cannot wait for the first FIS34 reliably.  Blindly
  issuing SRST to spinning-up device often results in command issue
  failure or timeout, causing extended delay.  For these controllers,
  ata_std_prereset() explicitly waits ATA_SPINUP_WAIT (currently 8s)
  to give newly attached device time to spin up, then issues reset.
  Note that failing to getting ready in ATA_SPINUP_WAIT is not
  critical.  libata will retry.  So, the timeout needs to be long
  enough to spin up most devices.

LLDDs can tell ata_std_prereset() which of above action is needed with
ATA_FLAG_HRST_TO_RESUME and ATA_FLAG_CANT_WAIT_FIS34 flags.  These
flags are PHY-specific property and will be moved to ata_link later.

While at it, this patch unifies function typedef's such that they all
have named arguments.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

Last minute change broke error condition check in ata_std_prereset()
and ata_wait_spinup().  This is the updated patch.  git tree has been
updated accordingly.  No other patch is affected.

 drivers/scsi/ahci.c         |    3 +-
 drivers/scsi/libata-bmdma.c |   11 ++++--
 drivers/scsi/libata-core.c  |   85 +++++++++++++++++++++++++++++++++++++++++++
 drivers/scsi/libata-eh.c    |   60 ++++++++++++++++++++++++++----
 drivers/scsi/sata_sil24.c   |    3 +-
 include/linux/libata.h      |   24 +++++++++---
 6 files changed, 165 insertions(+), 21 deletions(-)

44c3cba6ef79db2eb102894cfd73cd49cff37e05
diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index 45fd71d..8493b02 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -1026,7 +1026,8 @@ static void ahci_error_handler(struct at
 	}
 
 	/* perform recovery */
-	ata_do_eh(ap, ahci_softreset, ahci_hardreset, ahci_postreset);
+	ata_do_eh(ap, ata_std_prereset, ahci_softreset, ahci_hardreset,
+		  ahci_postreset);
 }
 
 static void ahci_post_internal_cmd(struct ata_queued_cmd *qc)
diff --git a/drivers/scsi/libata-bmdma.c b/drivers/scsi/libata-bmdma.c
index 6d30d2c..4bc0537 100644
--- a/drivers/scsi/libata-bmdma.c
+++ b/drivers/scsi/libata-bmdma.c
@@ -695,6 +695,7 @@ void ata_bmdma_thaw(struct ata_port *ap)
 /**
  *	ata_bmdma_drive_eh - Perform EH with given methods for BMDMA controller
  *	@ap: port to handle error for
+ *	@prereset: prereset method (can be NULL)
  *	@softreset: softreset method (can be NULL)
  *	@hardreset: hardreset method (can be NULL)
  *	@postreset: postreset method (can be NULL)
@@ -710,8 +711,9 @@ void ata_bmdma_thaw(struct ata_port *ap)
  *	LOCKING:
  *	Kernel thread context (may sleep)
  */
-void ata_bmdma_drive_eh(struct ata_port *ap, ata_reset_fn_t softreset,
-			ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
+void ata_bmdma_drive_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
+			ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
+			ata_postreset_fn_t postreset)
 {
 	struct ata_host_set *host_set = ap->host_set;
 	struct ata_eh_context *ehc = &ap->eh_context;
@@ -759,7 +761,7 @@ void ata_bmdma_drive_eh(struct ata_port 
 		ata_eh_thaw_port(ap);
 
 	/* PIO and DMA engines have been stopped, perform recovery */
-	ata_do_eh(ap, softreset, hardreset, postreset);
+	ata_do_eh(ap, prereset, softreset, hardreset, postreset);
 }
 
 /**
@@ -779,7 +781,8 @@ void ata_bmdma_error_handler(struct ata_
 	if (sata_scr_valid(ap))
 		hardreset = sata_std_hardreset;
 
-	ata_bmdma_drive_eh(ap, ata_std_softreset, hardreset, ata_std_postreset);
+	ata_bmdma_drive_eh(ap, ata_std_prereset, ata_std_softreset, hardreset,
+			   ata_std_postreset);
 }
 
 /**
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 9763395..cafc660 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2520,6 +2520,90 @@ int sata_phy_resume(struct ata_port *ap,
 	return sata_phy_debounce(ap, params);
 }
 
+static void ata_wait_spinup(struct ata_port *ap)
+{
+	struct ata_eh_context *ehc = &ap->eh_context;
+	unsigned long end, secs;
+	int rc;
+
+	/* first, debounce phy if SATA */
+	if (ap->cbl == ATA_CBL_SATA) {
+		rc = sata_phy_debounce(ap, sata_deb_timing_eh);
+
+		/* if debounced successfully and offline, no need to wait */
+		if ((rc == 0 || rc == -EOPNOTSUPP) && ata_port_offline(ap))
+			return;
+	}
+
+	/* okay, let's give the drive time to spin up */
+	end = ehc->i.hotplug_timestamp + ATA_SPINUP_WAIT * HZ / 1000;
+	secs = ((end - jiffies) + HZ - 1) / HZ;
+
+	if (time_after(jiffies, end))
+		return;
+
+	if (secs > 5)
+		ata_port_printk(ap, KERN_INFO, "waiting for device to spin up "
+				"(%lu secs)\n", secs);
+
+	schedule_timeout_uninterruptible(end - jiffies);
+}
+
+/**
+ *	ata_std_prereset - prepare for reset
+ *	@ap: ATA port to be reset
+ *
+ *	@ap is about to be reset.  Initialize it.
+ *
+ *	LOCKING:
+ *	Kernel thread context (may sleep)
+ *
+ *	RETURNS:
+ *	0 on success, -errno otherwise.
+ */
+int ata_std_prereset(struct ata_port *ap)
+{
+	struct ata_eh_context *ehc = &ap->eh_context;
+	const unsigned long *timing;
+	int rc;
+
+	/* hotplug? */
+	if (ehc->i.flags & ATA_EHI_HOTPLUGGED) {
+		if (ap->flags & ATA_FLAG_HRST_TO_RESUME)
+			ehc->i.action |= ATA_EH_HARDRESET;
+		if (ap->flags & ATA_FLAG_SKIP_D2H_BSY)
+			ata_wait_spinup(ap);
+	}
+
+	/* if we're about to do hardreset, nothing more to do */
+	if (ehc->i.action & ATA_EH_HARDRESET)
+		return 0;
+
+	/* if SATA, resume phy */
+	if (ap->cbl == ATA_CBL_SATA) {
+		if (ap->flags & ATA_FLAG_LOADING)
+			timing = sata_deb_timing_boot;
+		else
+			timing = sata_deb_timing_eh;
+
+		rc = sata_phy_resume(ap, timing);
+		if (rc && rc != -EOPNOTSUPP) {
+			/* phy resume failed */
+			ata_port_printk(ap, KERN_WARNING, "failed to resume "
+					"link for reset (errno=%d)\n", rc);
+			return rc;
+		}
+	}
+
+	/* Wait for !BSY if the controller can wait for the first D2H
+	 * Reg FIS and we don't know that no device is attached.
+	 */
+	if (!(ap->flags & ATA_FLAG_SKIP_D2H_BSY) && !ata_port_offline(ap))
+		ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT);
+
+	return 0;
+}
+
 /**
  *	ata_std_probeinit - initialize probing
  *	@ap: port to be probed
@@ -5834,6 +5918,7 @@ EXPORT_SYMBOL_GPL(sata_phy_reset);
 EXPORT_SYMBOL_GPL(__sata_phy_reset);
 EXPORT_SYMBOL_GPL(ata_bus_reset);
 EXPORT_SYMBOL_GPL(ata_std_probeinit);
+EXPORT_SYMBOL_GPL(ata_std_prereset);
 EXPORT_SYMBOL_GPL(ata_std_softreset);
 EXPORT_SYMBOL_GPL(sata_std_hardreset);
 EXPORT_SYMBOL_GPL(ata_std_postreset);
diff --git a/drivers/scsi/libata-eh.c b/drivers/scsi/libata-eh.c
index b88f492..ab2c640 100644
--- a/drivers/scsi/libata-eh.c
+++ b/drivers/scsi/libata-eh.c
@@ -1280,20 +1280,58 @@ static void ata_eh_report(struct ata_por
 	}
 }
 
-static int ata_eh_reset(struct ata_port *ap, ata_reset_fn_t softreset,
+static int ata_eh_reset(struct ata_port *ap,
+			ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
 			ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
 {
 	struct ata_eh_context *ehc = &ap->eh_context;
 	unsigned int classes[ATA_MAX_DEVICES];
 	int tries = ATA_EH_RESET_TRIES;
+	unsigned int action;
 	ata_reset_fn_t reset;
 	int i, rc;
 
+	/* Determine which reset to use and record in ehc->i.action.
+	 * prereset() may examine and modify it.
+	 */
+	action = ehc->i.action;
+	ehc->i.action &= ~ATA_EH_RESET_MASK;
 	if (softreset && (!hardreset || (!sata_set_spd_needed(ap) &&
-					 !(ehc->i.action & ATA_EH_HARDRESET))))
-		reset = softreset;
+					 !(action & ATA_EH_HARDRESET))))
+		ehc->i.action |= ATA_EH_SOFTRESET;
 	else
+		ehc->i.action |= ATA_EH_HARDRESET;
+
+	if (prereset) {
+		rc = prereset(ap);
+		if (rc) {
+			ata_port_printk(ap, KERN_ERR,
+					"prereset failed (errno=%d)\n", rc);
+			return rc;
+		}
+	}
+
+	/* prereset() might have modified ehc->i.action */
+	if (ehc->i.action & ATA_EH_HARDRESET)
 		reset = hardreset;
+	else if (ehc->i.action & ATA_EH_SOFTRESET)
+		reset = softreset;
+	else {
+		/* prereset told us not to reset, bang classes and return */
+		for (i = 0; i < ATA_MAX_DEVICES; i++)
+			classes[i] = ATA_DEV_NONE;
+		return 0;
+	}
+
+	/* did prereset() screw up?  if so, fix up to avoid oopsing */
+	if (!reset) {
+		ata_port_printk(ap, KERN_ERR, "BUG: prereset() requested "
+				"invalid reset type\n");
+		if (softreset)
+			reset = softreset;
+		else
+			reset = hardreset;
+	}
 
  retry:
 	ata_port_printk(ap, KERN_INFO, "%s resetting port\n",
@@ -1386,6 +1424,7 @@ static int ata_port_nr_enabled(struct at
 /**
  *	ata_eh_recover - recover host port after error
  *	@ap: host port to recover
+ *	@prereset: prereset method (can be NULL)
  *	@softreset: softreset method (can be NULL)
  *	@hardreset: hardreset method (can be NULL)
  *	@postreset: postreset method (can be NULL)
@@ -1402,8 +1441,8 @@ static int ata_port_nr_enabled(struct at
  *	RETURNS:
  *	0 on success, -errno on failure.
  */
-static int ata_eh_recover(struct ata_port *ap, ata_reset_fn_t softreset,
-			  ata_reset_fn_t hardreset,
+static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
+			  ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
 			  ata_postreset_fn_t postreset)
 {
 	struct ata_eh_context *ehc = &ap->eh_context;
@@ -1431,7 +1470,8 @@ static int ata_eh_recover(struct ata_por
 	if (ehc->i.action & ATA_EH_RESET_MASK) {
 		ata_eh_freeze_port(ap);
 
-		rc = ata_eh_reset(ap, softreset, hardreset, postreset);
+		rc = ata_eh_reset(ap, prereset, softreset, hardreset,
+				  postreset);
 		if (rc) {
 			ata_port_printk(ap, KERN_ERR,
 					"reset failed, giving up\n");
@@ -1548,6 +1588,7 @@ static void ata_eh_finish(struct ata_por
 /**
  *	ata_do_eh - do standard error handling
  *	@ap: host port to handle error for
+ *	@prereset: prereset method (can be NULL)
  *	@softreset: softreset method (can be NULL)
  *	@hardreset: hardreset method (can be NULL)
  *	@postreset: postreset method (can be NULL)
@@ -1557,11 +1598,12 @@ static void ata_eh_finish(struct ata_por
  *	LOCKING:
  *	Kernel thread context (may sleep).
  */
-void ata_do_eh(struct ata_port *ap, ata_reset_fn_t softreset,
-	       ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
+void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
+	       ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
+	       ata_postreset_fn_t postreset)
 {
 	ata_eh_autopsy(ap);
 	ata_eh_report(ap);
-	ata_eh_recover(ap, softreset, hardreset, postreset);
+	ata_eh_recover(ap, prereset, softreset, hardreset, postreset);
 	ata_eh_finish(ap);
 }
diff --git a/drivers/scsi/sata_sil24.c b/drivers/scsi/sata_sil24.c
index 4c76f05..26d7c54 100644
--- a/drivers/scsi/sata_sil24.c
+++ b/drivers/scsi/sata_sil24.c
@@ -912,7 +912,8 @@ static void sil24_error_handler(struct a
 	}
 
 	/* perform recovery */
-	ata_do_eh(ap, sil24_softreset, sil24_hardreset, ata_std_postreset);
+	ata_do_eh(ap, ata_std_prereset, sil24_softreset, sil24_hardreset,
+		  ata_std_postreset);
 }
 
 static void sil24_post_internal_cmd(struct ata_queued_cmd *qc)
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 838b11a..8822340 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -261,6 +261,15 @@ enum {
 	ATA_PROBE_MAX_TRIES	= 3,
 	ATA_EH_RESET_TRIES	= 3,
 	ATA_EH_DEV_TRIES	= 3,
+
+	/* Drive spinup time (time from power-on to the first FIS34)
+	 * in msecs - 8s currently.  Failing to get ready in this time
+	 * isn't critical.  It will result in reset failure for
+	 * controllers which can't wait for the first FIS34.  libata
+	 * will retry, so it just has to be long enough to spin up
+	 * most devices.
+	 */
+	ATA_SPINUP_WAIT		= 8000,
 };
 
 enum hsm_task_states {
@@ -293,9 +302,10 @@ struct ata_queued_cmd;
 
 /* typedefs */
 typedef void (*ata_qc_cb_t) (struct ata_queued_cmd *qc);
-typedef void (*ata_probeinit_fn_t)(struct ata_port *);
-typedef int (*ata_reset_fn_t)(struct ata_port *, unsigned int *);
-typedef void (*ata_postreset_fn_t)(struct ata_port *ap, unsigned int *);
+typedef void (*ata_probeinit_fn_t)(struct ata_port *ap);
+typedef int (*ata_prereset_fn_t)(struct ata_port *ap);
+typedef int (*ata_reset_fn_t)(struct ata_port *ap, unsigned int *classes);
+typedef void (*ata_postreset_fn_t)(struct ata_port *ap, unsigned int *classes);
 
 struct ata_ioports {
 	unsigned long		cmd_addr;
@@ -621,6 +631,7 @@ extern int ata_drive_probe_reset(struct 
 			ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
 			ata_postreset_fn_t postreset, unsigned int *classes);
 extern void ata_std_probeinit(struct ata_port *ap);
+extern int ata_std_prereset(struct ata_port *ap);
 extern int ata_std_softreset(struct ata_port *ap, unsigned int *classes);
 extern int sata_std_hardreset(struct ata_port *ap, unsigned int *class);
 extern void ata_std_postreset(struct ata_port *ap, unsigned int *classes);
@@ -704,7 +715,7 @@ extern u8   ata_bmdma_status(struct ata_
 extern void ata_bmdma_irq_clear(struct ata_port *ap);
 extern void ata_bmdma_freeze(struct ata_port *ap);
 extern void ata_bmdma_thaw(struct ata_port *ap);
-extern void ata_bmdma_drive_eh(struct ata_port *ap,
+extern void ata_bmdma_drive_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
 			       ata_reset_fn_t softreset,
 			       ata_reset_fn_t hardreset,
 			       ata_postreset_fn_t postreset);
@@ -782,8 +793,9 @@ extern void ata_eh_thaw_port(struct ata_
 extern void ata_eh_qc_complete(struct ata_queued_cmd *qc);
 extern void ata_eh_qc_retry(struct ata_queued_cmd *qc);
 
-extern void ata_do_eh(struct ata_port *ap, ata_reset_fn_t softreset,
-		      ata_reset_fn_t hardreset, ata_postreset_fn_t postreset);
+extern void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
+		      ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
+		      ata_postreset_fn_t postreset);
 
 /*
  * printk helpers
-- 
1.3.2

Re: [PATCH 11/12] (updated) libata-hp-prep: add prereset() method and implement ata_std_prereset()

[Jeff Garzik]

Tejun Heo wrote:
> With hotplug, every reset might be a probing reset and thus something
> similar to probe_init() is needed.  prereset() method is called before
> a series of resets to a port and is the counterpart of postreset().
> prereset() can tell EH to use different type of reset or skip reset by
> modifying ehc->i.action.
> 
> This patch also implements ata_std_prereset().  Most controllers
> should be able to use this function directly or with some wrapping.
> After hotplug, different controllers need different actions to resume
> the PHY and detect the newly attached device.  Controllers can be
> categorized as follows.
> 
> * Controllers which can wait for the first FIS34 after hotplug.  Note
>   that if the waiting is implemented by polling TF status, there needs
>   to be a way to set BSY on PHY status change.  It can be implemented
>   by hardware or with the help of the driver.
> 
> * Controllers which can wait for the first FIS34 after sending
>   COMRESET.  These controllers need to issue COMRESET to wait for the
>   first FIS.  Note that the received FIS34 could be the first FIS34
>   after POR (power-on-reset) or FIS34 in response to the COMRESET.
>   Some controllers use COMRESET as TF status synchronization point and
>   clear TF automatically (sata_sil).
> 
> * Controllers which cannot wait for the first FIS34 reliably.  Blindly
>   issuing SRST to spinning-up device often results in command issue
>   failure or timeout, causing extended delay.  For these controllers,
>   ata_std_prereset() explicitly waits ATA_SPINUP_WAIT (currently 8s)
>   to give newly attached device time to spin up, then issues reset.
>   Note that failing to getting ready in ATA_SPINUP_WAIT is not
>   critical.  libata will retry.  So, the timeout needs to be long
>   enough to spin up most devices.
> 
> LLDDs can tell ata_std_prereset() which of above action is needed with
> ATA_FLAG_HRST_TO_RESUME and ATA_FLAG_CANT_WAIT_FIS34 flags.  These
> flags are PHY-specific property and will be moved to ata_link later.
> 
> While at it, this patch unifies function typedef's such that they all
> have named arguments.
> 
> Signed-off-by: Tejun Heo <htejun@gmail.com>

ACK, provided that you banish all mentions of "FIS34" from the patch 
description.

"D2H FIS" is far more understandable to the average human.

	Jeff

[PATCH 05/12] libata-hp-prep: use __ata_scsi_find_dev()

[Tejun Heo]

Convert direct sdev -> dev lookup to __ata_scsi_find_dev().

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/libata-scsi.c |   16 ++++++----------
 1 files changed, 6 insertions(+), 10 deletions(-)

bea7ebdc48efc94a29ada2a32a648d8e5e545427
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 9adc5c1..95e5c23 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -399,7 +399,7 @@ void ata_dump_status(unsigned id, struct
 int ata_scsi_device_resume(struct scsi_device *sdev)
 {
 	struct ata_port *ap = ata_shost_to_port(sdev->host);
-	struct ata_device *dev = &ap->device[sdev->id];
+	struct ata_device *dev = __ata_scsi_find_dev(ap, sdev);
 
 	return ata_device_resume(dev);
 }
@@ -407,7 +407,7 @@ int ata_scsi_device_resume(struct scsi_d
 int ata_scsi_device_suspend(struct scsi_device *sdev, pm_message_t state)
 {
 	struct ata_port *ap = ata_shost_to_port(sdev->host);
-	struct ata_device *dev = &ap->device[sdev->id];
+	struct ata_device *dev = __ata_scsi_find_dev(ap, sdev);
 
 	return ata_device_suspend(dev, state);
 }
@@ -713,19 +713,15 @@ static void ata_scsi_dev_config(struct s
 
 int ata_scsi_slave_config(struct scsi_device *sdev)
 {
+	struct ata_port *ap = ata_shost_to_port(sdev->host);
+	struct ata_device *dev = __ata_scsi_find_dev(ap, sdev);
+
 	ata_scsi_sdev_config(sdev);
 
 	blk_queue_max_phys_segments(sdev->request_queue, LIBATA_MAX_PRD);
 
-	if (sdev->id < ATA_MAX_DEVICES) {
-		struct ata_port *ap;
-		struct ata_device *dev;
-
-		ap = ata_shost_to_port(sdev->host);
-		dev = &ap->device[sdev->id];
-
+	if (dev)
 		ata_scsi_dev_config(sdev, dev);
-	}
 
 	return 0;	/* scsi layer doesn't check return value, sigh */
 }
-- 
1.3.2

[PATCH 06/12] libata-hp-prep: implement ap->hw_sata_spd_limit

[Tejun Heo]

Add ap->hw_sata_spd_limit and initialize it once during the boot
initialization (or driver load initialization).  ap->sata_spd_limit is
reset to ap->hw_sata_spd_limit on hotplug.  This prevents spd limits
introduced by earlier devices from affecting new devices.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/libata-core.c |   21 ++++++++++++---------
 include/linux/libata.h     |    1 +
 2 files changed, 13 insertions(+), 9 deletions(-)

0329251e5f08a8110541cbd2e64adb29c340c5d7
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index fc9989d..83fb9dd 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2466,17 +2466,9 @@ static int sata_phy_resume(struct ata_po
  */
 void ata_std_probeinit(struct ata_port *ap)
 {
-	u32 scontrol;
-
 	/* resume link */
 	sata_phy_resume(ap);
 
-	/* init sata_spd_limit to the current value */
-	if (sata_scr_read(ap, SCR_CONTROL, &scontrol) == 0) {
-		int spd = (scontrol >> 4) & 0xf;
-		ap->sata_spd_limit &= (1 << spd) - 1;
-	}
-
 	/* wait for device */
 	if (ata_port_online(ap))
 		ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT);
@@ -5155,6 +5147,9 @@ void ata_dev_init(struct ata_device *dev
 	struct ata_port *ap = dev->ap;
 	unsigned long flags;
 
+	/* SATA spd limit is bound to the first device */
+	ap->sata_spd_limit = ap->hw_sata_spd_limit;
+
 	/* High bits of dev->flags are used to record warm plug
 	 * requests which occur asynchronously.  Synchronize using
 	 * host_set lock.
@@ -5210,7 +5205,7 @@ static void ata_host_init(struct ata_por
 	ap->udma_mask = ent->udma_mask;
 	ap->flags |= ent->host_flags;
 	ap->ops = ent->port_ops;
-	ap->sata_spd_limit = UINT_MAX;
+	ap->hw_sata_spd_limit = UINT_MAX;
 	ap->active_tag = ATA_TAG_POISON;
 	ap->last_ctl = 0xFF;
 	ap->msg_enable = ATA_MSG_DRV;
@@ -5374,10 +5369,18 @@ int ata_device_add(const struct ata_prob
 	DPRINTK("probe begin\n");
 	for (i = 0; i < count; i++) {
 		struct ata_port *ap;
+		u32 scontrol;
 		int rc;
 
 		ap = host_set->ports[i];
 
+		/* init sata_spd_limit to the current value */
+		if (sata_scr_read(ap, SCR_CONTROL, &scontrol) == 0) {
+			int spd = (scontrol >> 4) & 0xf;
+			ap->hw_sata_spd_limit &= (1 << spd) - 1;
+		}
+		ap->sata_spd_limit = ap->hw_sata_spd_limit;
+
 		DPRINTK("ata%u: bus probe begin\n", ap->id);
 		rc = ata_bus_probe(ap);
 		DPRINTK("ata%u: bus probe end\n", ap->id);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 20c6aa1..c42ea93 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -488,6 +488,7 @@ struct ata_port {
 	unsigned int		mwdma_mask;
 	unsigned int		udma_mask;
 	unsigned int		cbl;	/* cable type; ATA_CBL_xxx */
+	unsigned int		hw_sata_spd_limit;
 	unsigned int		sata_spd_limit;	/* SATA PHY speed limit */
 
 	/* record runtime error info, protected by host_set lock */
-- 
1.3.2

[PATCH 07/12] libata-hp-prep: store attached SCSI device

[Tejun Heo]

Add device persistent field dev->sdev and store the attached SCSI
device.  With hotplug, libata needs to know the attached SCSI device
to offline and detach it, but scsi_device_lookup() cannot be used
because libata will reuse SCSI ID numbers - dead but not gone devices
(due to zombie opens, etc...) interfere with the lookup.

dev->sdev doesn't hold reference to the SCSI device.  It's cleared
when the SCSI device goes away.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/libata-scsi.c |   14 ++++++++++----
 include/linux/libata.h     |    1 +
 2 files changed, 11 insertions(+), 4 deletions(-)

16098cb84a40faee6726ff51371e9aa17e018a5f
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 95e5c23..a1caf3f 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -2743,16 +2743,22 @@ void ata_scsi_simulate(struct ata_device
 
 void ata_scsi_scan_host(struct ata_port *ap)
 {
-	struct ata_device *dev;
 	unsigned int i;
 
 	if (ap->flags & ATA_FLAG_DISABLED)
 		return;
 
 	for (i = 0; i < ATA_MAX_DEVICES; i++) {
-		dev = &ap->device[i];
+		struct ata_device *dev = &ap->device[i];
+		struct scsi_device *sdev;
+
+		if (!ata_dev_enabled(dev) || dev->sdev)
+			continue;
 
-		if (ata_dev_enabled(dev))
-			scsi_scan_target(&ap->host->shost_gendev, 0, i, 0, 0);
+		sdev = __scsi_add_device(ap->host, 0, i, 0, NULL);
+		if (!IS_ERR(sdev)) {
+			dev->sdev = sdev;
+			scsi_device_put(sdev);
+		}
 	}
 }
diff --git a/include/linux/libata.h b/include/linux/libata.h
index c42ea93..54b2259 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -412,6 +412,7 @@ struct ata_device {
 	struct ata_port		*ap;
 	unsigned int		devno;		/* 0 or 1 */
 	unsigned long		flags;		/* ATA_DFLAG_xxx */
+	struct scsi_device	*sdev;		/* attached SCSI device */
 	/* n_sector is used as CLEAR_OFFSET, read comment above CLEAR_OFFSET */
 	u64			n_sectors;	/* size of device, if ATA */
 	unsigned int		class;		/* ATA_DEV_xxx */
-- 
1.3.2

Re: [PATCH 07/12] libata-hp-prep: store attached SCSI device

[zhao, forrest]

On Mon, 2006-05-29 at 15:25 +0900, Tejun Heo wrote:
> @@ -2743,16 +2743,22 @@ void ata_scsi_simulate(struct ata_device
>  
>  void ata_scsi_scan_host(struct ata_port *ap)
>  {
> -	struct ata_device *dev;
>  	unsigned int i;
>  
>  	if (ap->flags & ATA_FLAG_DISABLED)
>  		return;
>  
>  	for (i = 0; i < ATA_MAX_DEVICES; i++) {
> -		dev = &ap->device[i];
> +		struct ata_device *dev = &ap->device[i];
> +		struct scsi_device *sdev;
> +
> +		if (!ata_dev_enabled(dev) || dev->sdev)
> +			continue;
>  
> -		if (ata_dev_enabled(dev))
> -			scsi_scan_target(&ap->host->shost_gendev, 0, i, 0, 0);
> +		sdev = __scsi_add_device(ap->host, 0, i, 0, NULL);
Is it better to use macro scsi_add_device() than invoking
__scsi_add_device() directly here? I know this is only a trivial change.

> +		if (!IS_ERR(sdev)) {
> +			dev->sdev = sdev;
> +			scsi_device_put(sdev);
> +		}
>  	}
>  }

Thanks,
Forrest

Re: [PATCH 07/12] libata-hp-prep: store attached SCSI device

[Tejun Heo]

zhao, forrest wrote:
> On Mon, 2006-05-29 at 15:25 +0900, Tejun Heo wrote:
>> @@ -2743,16 +2743,22 @@ void ata_scsi_simulate(struct ata_device
>>  
>>  void ata_scsi_scan_host(struct ata_port *ap)
>>  {
>> -	struct ata_device *dev;
>>  	unsigned int i;
>>  
>>  	if (ap->flags & ATA_FLAG_DISABLED)
>>  		return;
>>  
>>  	for (i = 0; i < ATA_MAX_DEVICES; i++) {
>> -		dev = &ap->device[i];
>> +		struct ata_device *dev = &ap->device[i];
>> +		struct scsi_device *sdev;
>> +
>> +		if (!ata_dev_enabled(dev) || dev->sdev)
>> +			continue;
>>  
>> -		if (ata_dev_enabled(dev))
>> -			scsi_scan_target(&ap->host->shost_gendev, 0, i, 0, 0);
>> +		sdev = __scsi_add_device(ap->host, 0, i, 0, NULL);
> Is it better to use macro scsi_add_device() than invoking
> __scsi_add_device() directly here? I know this is only a trivial change.

Again, could be.  The change is mostly cosmetic.  I like the current
form because it explicitly signifies that libata doesn't hold reference
to sdev.

-- 
tejun

Re: [PATCH 07/12] libata-hp-prep: store attached SCSI device

[Jeff Garzik]

Tejun Heo wrote:
> dev->sdev doesn't hold reference to the SCSI device.  It's cleared
> when the SCSI device goes away.

ACK patches 5-7, though I consider the above quoted statement somewhat 
questionable...  _why_ not hold a reference?

	Jeff

Re: [PATCH 07/12] libata-hp-prep: store attached SCSI device

[Tejun Heo]

Jeff Garzik wrote:
> Tejun Heo wrote:
>> dev->sdev doesn't hold reference to the SCSI device.  It's cleared
>> when the SCSI device goes away.
> 
> ACK patches 5-7, though I consider the above quoted statement somewhat 
> questionable...  _why_ not hold a reference?

libata shouldn't affect the lifetime of the scsi device.  When the sdev 
disappears, dev->sdev should go too.  It's easy to carry an extra 
reference but it wouldn't mean anything - the reference will be 
increased on attach and should be decreased with the device lifetime 
reference, so I thought it would be better to make it explicit that 
libata doesn't affect sdev's lifetime by not holding any extra reference 
to it.

-- 
tejun

[PATCH 03/12] libata-hp-prep: make some ata_device fields persistent

[Tejun Heo]

Lifetimes of some fields span over device plugging/unplugging.  This
patch moves such persistent fields to the top of ata_device and
separate them with ATA_DEVICE_CLEAR_OFFSET.  Fields above the offset
are initialized once during host initializatino while all other fields
are cleared before hotplugging.  Currently ->ap, devno and part of
flags are persistent.

Note that flags is partially cleared while holding host_set lock.
This is to synchronize with later warm plug implementation which will
record hotplug request in dev->flags.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/libata-core.c |   14 ++++++++++++--
 include/linux/libata.h     |   11 +++++++++--
 2 files changed, 21 insertions(+), 4 deletions(-)

a615dbf0ff4deac11925b7be6916caed19a66f3e
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 84afb59..fc9989d 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -5153,9 +5153,18 @@ static void ata_host_remove(struct ata_p
 void ata_dev_init(struct ata_device *dev)
 {
 	struct ata_port *ap = dev->ap;
+	unsigned long flags;
+
+	/* High bits of dev->flags are used to record warm plug
+	 * requests which occur asynchronously.  Synchronize using
+	 * host_set lock.
+	 */
+	spin_lock_irqsave(&ap->host_set->lock, flags);
+	dev->flags &= ~ATA_DFLAG_INIT_MASK;
+	spin_unlock_irqrestore(&ap->host_set->lock, flags);
 
-	memset((void *)dev, 0, sizeof(*dev));
-	dev->devno = dev - ap->device;
+	memset((void *)dev + ATA_DEVICE_CLEAR_OFFSET, 0,
+	       sizeof(*dev) - ATA_DEVICE_CLEAR_OFFSET);
 	dev->pio_mask = UINT_MAX;
 	dev->mwdma_mask = UINT_MAX;
 	dev->udma_mask = UINT_MAX;
@@ -5217,6 +5226,7 @@ static void ata_host_init(struct ata_por
 	for (i = 0; i < ATA_MAX_DEVICES; i++) {
 		struct ata_device *dev = &ap->device[i];
 		dev->ap = ap;
+		dev->devno = i;
 		ata_dev_init(dev);
 	}
 
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 4f67c43..20c6aa1 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -130,6 +130,7 @@ enum {
 	ATA_DFLAG_CFG_MASK	= (1 << 8) - 1,
 
 	ATA_DFLAG_PIO		= (1 << 8), /* device currently in PIO mode */
+	ATA_DFLAG_INIT_MASK	= (1 << 16) - 1,
 
 	ATA_DFLAG_DETACH	= (1 << 16),
 	ATA_DFLAG_DETACHED	= (1 << 17),
@@ -409,10 +410,11 @@ struct ata_ering {
 
 struct ata_device {
 	struct ata_port		*ap;
-	u64			n_sectors;	/* size of device, if ATA */
+	unsigned int		devno;		/* 0 or 1 */
 	unsigned long		flags;		/* ATA_DFLAG_xxx */
+	/* n_sector is used as CLEAR_OFFSET, read comment above CLEAR_OFFSET */
+	u64			n_sectors;	/* size of device, if ATA */
 	unsigned int		class;		/* ATA_DEV_xxx */
-	unsigned int		devno;		/* 0 or 1 */
 	u16			id[ATA_ID_WORDS]; /* IDENTIFY xxx DEVICE data */
 	u8			pio_mode;
 	u8			dma_mode;
@@ -438,6 +440,11 @@ struct ata_device {
 	struct ata_ering	ering;
 };
 
+/* Offset into struct ata_device.  Fields above it are maintained
+ * acress device init.  Fields below are zeroed.
+ */
+#define ATA_DEVICE_CLEAR_OFFSET		offsetof(struct ata_device, n_sectors)
+
 struct ata_eh_info {
 	struct ata_device	*dev;		/* offending device */
 	u32			serror;		/* SError from LLDD */
-- 
1.3.2

Re: [PATCH 03/12] libata-hp-prep: make some ata_device fields persistent

[Jeff Garzik]

Tejun Heo wrote:
> Lifetimes of some fields span over device plugging/unplugging.  This
> patch moves such persistent fields to the top of ata_device and
> separate them with ATA_DEVICE_CLEAR_OFFSET.  Fields above the offset
> are initialized once during host initializatino while all other fields
> are cleared before hotplugging.  Currently ->ap, devno and part of
> flags are persistent.
> 
> Note that flags is partially cleared while holding host_set lock.
> This is to synchronize with later warm plug implementation which will
> record hotplug request in dev->flags.
> 
> Signed-off-by: Tejun Heo <htejun@gmail.com>

ACK 1-3

[PATCHSET 01/03] prep for hotplug support, take 5

[Tejun Heo]

Hello,

This is part of patchset series described in [T].

This is the fourth take of add-hotplug-support patchset.  Changes from
the last take[L] are.

* ata_scsi_wq renamed to ata_aux_wq

* msleep(200) added between phy wakeup and the first SStatus polling.

* SLAVE_POSS check dropped from ata_find_dev()

* s/FIS34/D2H FIS/g

This patchset is against

  upstream (ef2824073fba9def3cf122e89cc485f66dd71f70)
  + [1] set-PIO-0-after-successful-EH-reset
  + [2] shift-host-flag-constants
  + [3] implement-ata_eh_wait

Thanks.

--
tejun

[T] http://article.gmane.org/gmane.linux.ide/11012
[L] http://article.gmane.org/gmane.linux.ide/10892
[1] http://article.gmane.org/gmane.linux.ide/10890
[2] http://article.gmane.org/gmane.linux.ide/11010
[3] http://article.gmane.org/gmane.linux.ide/11011

[PATCH 04/12] libata-hp-prep: update ata_scsi_find_dev() and friends

[Tejun Heo]

Separate out ata_find_dev() and __ata_scsi_find_dev() from
ata_scsi_find_dev().  These will be used by later hotplug
implementation.

Signed-off-by: Tejun Heo <htejun@gmail.com>

---

 drivers/scsi/libata-scsi.c |   40 +++++++++++++++++++++++++---------------
 1 files changed, 25 insertions(+), 15 deletions(-)

ab5b3a5b2d887ce63f8c6a7fcb9f5c07ca4b4d43
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 9e5cb9f..b45b8b3 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -52,8 +52,12 @@ #include "libata.h"
 #define SECTOR_SIZE	512
 
 typedef unsigned int (*ata_xlat_func_t)(struct ata_queued_cmd *qc, const u8 *scsicmd);
-static struct ata_device *
-ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device *scsidev);
+
+static struct ata_device * __ata_scsi_find_dev(struct ata_port *ap,
+					const struct scsi_device *scsidev);
+static struct ata_device * ata_scsi_find_dev(struct ata_port *ap,
+					    const struct scsi_device *scsidev);
+
 
 #define RW_RECOVERY_MPAGE 0x1
 #define RW_RECOVERY_MPAGE_LEN 12
@@ -2308,6 +2312,23 @@ static unsigned int atapi_xlat(struct at
 	return 0;
 }
 
+static struct ata_device * ata_find_dev(struct ata_port *ap, int id)
+{
+	if (likely(id < ATA_MAX_DEVICES))
+		return &ap->device[id];
+	return NULL;
+}
+
+static struct ata_device * __ata_scsi_find_dev(struct ata_port *ap,
+					const struct scsi_device *scsidev)
+{
+	/* skip commands not addressed to targets we simulate */
+	if (unlikely(scsidev->channel || scsidev->lun))
+		return NULL;
+
+	return ata_find_dev(ap, scsidev->id);
+}
+
 /**
  *	ata_scsi_find_dev - lookup ata_device from scsi_cmnd
  *	@ap: ATA port to which the device is attached
@@ -2324,23 +2345,12 @@ static unsigned int atapi_xlat(struct at
  *	RETURNS:
  *	Associated ATA device, or %NULL if not found.
  */
-
 static struct ata_device *
 ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device *scsidev)
 {
-	struct ata_device *dev;
-
-	/* skip commands not addressed to targets we simulate */
-	if (likely(scsidev->id < ATA_MAX_DEVICES))
-		dev = &ap->device[scsidev->id];
-	else
-		return NULL;
-
-	if (unlikely((scsidev->channel != 0) ||
-		     (scsidev->lun != 0)))
-		return NULL;
+	struct ata_device *dev = __ata_scsi_find_dev(ap, scsidev);
 
-	if (unlikely(!ata_dev_enabled(dev)))
+	if (unlikely(!dev || !ata_dev_enabled(dev)))
 		return NULL;
 
 	if (!atapi_enabled || (ap->flags & ATA_FLAG_NO_ATAPI)) {
-- 
1.3.2