[patch] ata: ahci: Enclosure Management via LED

[patch] ata: ahci: Enclosure Management via LED

[Kristen Carlson Accardi]

This patch implements Enclosure Management via the LED protocol.  See
the AHCI 1.1 spec for details.

Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
---
Ok, here's one that actually compiles...

 drivers/ata/ahci.c        |  154 ++++++++++++++++++++++++++++++++++++++++++++-
 drivers/ata/libata-scsi.c |    5 +-
 include/linux/libata.h    |    2 +
 3 files changed, 157 insertions(+), 4 deletions(-)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 2c686b4..27f8b3f 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -44,6 +44,7 @@
 #include <linux/dmi.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
 #include <linux/libata.h>
 
 #define DRV_NAME	"ahci"
@@ -92,6 +93,8 @@ enum {
 	HOST_IRQ_STAT		= 0x08, /* interrupt status */
 	HOST_PORTS_IMPL		= 0x0c, /* bitmap of implemented ports */
 	HOST_VERSION		= 0x10, /* AHCI spec. version compliancy */
+	HOST_EM_LOC		= 0x1c, /* Enclosure Management location */
+	HOST_EM_CTL		= 0x20, /* Enclosure Management Control */
 
 	/* HOST_CTL bits */
 	HOST_RESET		= (1 << 0),  /* reset controller; self-clear */
@@ -99,6 +102,7 @@ enum {
 	HOST_AHCI_EN		= (1 << 31), /* AHCI enabled */
 
 	/* HOST_CAP bits */
+	HOST_CAP_EMS		= (1 << 6),  /* Enclosure Management support */
 	HOST_CAP_SSC		= (1 << 14), /* Slumber capable */
 	HOST_CAP_PMP		= (1 << 17), /* Port Multiplier support */
 	HOST_CAP_CLO		= (1 << 24), /* Command List Override support */
@@ -193,6 +197,10 @@ enum {
 					  ATA_FLAG_ACPI_SATA | ATA_FLAG_AN |
 					  ATA_FLAG_IPM,
 	AHCI_LFLAG_COMMON		= ATA_LFLAG_SKIP_D2H_BSY,
+
+	/* em_ctl bits */
+	EM_CTL_RST			= (1 << 9), /* Reset */
+	EM_CTL_TM			= (1 << 8), /* Transmit Message */
 };
 
 struct ahci_cmd_hdr {
@@ -216,6 +224,7 @@ struct ahci_host_priv {
 	u32			port_map;	/* port map to use */
 	u32			saved_cap;	/* saved initial cap */
 	u32			saved_port_map;	/* saved initial port_map */
+	u32 			em_loc; /* enclosure management location */
 };
 
 struct ahci_port_priv {
@@ -231,6 +240,7 @@ struct ahci_port_priv {
 	unsigned int		ncq_saw_dmas:1;
 	unsigned int		ncq_saw_sdb:1;
 	u32 			intr_mask;	/* interrupts to enable */
+	u16			led_state;	/* saved current led state */
 };
 
 static int ahci_scr_read(struct ata_port *ap, unsigned int sc_reg, u32 *val);
@@ -572,6 +582,11 @@ static struct pci_driver ahci_pci_driver = {
 #endif
 };
 
+static int ahci_em_messages = 1;
+module_param(ahci_em_messages, int, 0444);
+/* add other LED protocol types when they become supported */
+MODULE_PARM_DESC(ahci_em_messages,
+	"Set AHCI Enclosure Management Message type (0 = disabled, 1 = LED");
 
 static inline int ahci_nr_ports(u32 cap)
 {
@@ -1082,6 +1097,118 @@ static int ahci_reset_controller(struct ata_host *host)
 	return 0;
 }
 
+/****** LED Enclosure Management routines ********/
+static int ahci_reset_em(struct ata_host *host)
+{
+	void __iomem *mmio = host->iomap[AHCI_PCI_BAR];
+	u32 em_ctl;
+
+	em_ctl = readl(mmio + HOST_EM_CTL);
+	if ((em_ctl & EM_CTL_TM) || (em_ctl & EM_CTL_RST))
+		return -EINVAL;
+
+	writel(em_ctl | EM_CTL_RST, mmio + HOST_EM_CTL);
+	return 0;
+}
+
+static int ahci_transmit_led_message(struct ata_port *ap, int led_num,
+			int state)
+{
+	struct ahci_host_priv *hpriv = ap->host->private_data;
+	void __iomem *mmio = ap->host->iomap[AHCI_PCI_BAR];
+	struct ahci_port_priv *pp = ap->private_data;
+	u32 em_ctl;
+	u32 message[] = {0, 0};
+	unsigned int flags;
+
+	spin_lock_irqsave(ap->lock, flags);
+
+	/*
+	 * if we are still busy transmitting a previous message,
+	 * do not allow
+	 */
+	em_ctl = readl(mmio + HOST_EM_CTL);
+	if (em_ctl & EM_CTL_TM) {
+		spin_unlock_irqrestore(ap->lock, flags);
+		return -EINVAL;
+	}
+
+	/*
+	 * create message header - this is all zero except for
+	 * the message size, which is 4 bytes.
+	 */
+	message[0] |= (4 << 8);
+
+	pp->led_state &= ~(9 << (3*led_num));
+
+	/*
+	 * create the actual message
+	 * XXX will need Port Multiplier support
+	 */
+	message[1] = (ap->port_no | (pp->led_state << 16));
+
+	/* LED bit locations are determined by the led_num */
+	message[1] |= (state << (16 + (3*led_num)));
+
+	/* write message to EM_LOC */
+	writel(message[0], mmio + hpriv->em_loc);
+	writel(message[1], mmio + hpriv->em_loc+4);
+
+	/* save off new led state */
+	pp->led_state = ((message[1] >> 16) & 0x00ff);
+
+	/*
+	 * tell hardware to transmit the message
+	 */
+	writel(em_ctl | EM_CTL_TM, mmio + HOST_EM_CTL);
+
+	spin_unlock_irqrestore(ap->lock, flags);
+	return 0;
+}
+
+static int ahci_led_store(struct device *dev, const char *buf, int num)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct ata_port *ap = ata_shost_to_port(sdev->host);
+	struct ata_device *atadev = ata_scsi_find_dev(ap, sdev);
+	int state;
+
+	if (!atadev || !ata_dev_enabled(atadev))
+		return -EINVAL;
+
+	state = simple_strtoul(buf, NULL, 0);
+	if (state != 0 && state != 1)
+		return -EINVAL;
+
+	return ahci_transmit_led_message(ap, num, state);
+}
+
+static ssize_t ahci_led_locate_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	int rc = ahci_led_store(dev, buf, 1);
+	if (!rc)
+		return count;
+	return rc;
+}
+static DEVICE_ATTR(locate, S_IWUSR | S_IRUGO, NULL, ahci_led_locate_store);
+
+static ssize_t ahci_led_fault_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	int rc = ahci_led_store(dev, buf, 2);
+	if (!rc)
+		return count;
+	return rc;
+}
+static DEVICE_ATTR(fault, S_IWUGO, NULL, ahci_led_fault_store);
+
+static struct device_attribute *ahci_em_led_attrs[] = {
+	&dev_attr_locate,
+	&dev_attr_fault,
+	NULL
+};
+
 static void ahci_port_init(struct pci_dev *pdev, struct ata_port *ap,
 			   int port_no, void __iomem *mmio,
 			   void __iomem *port_mmio)
@@ -2178,7 +2305,8 @@ static void ahci_print_info(struct ata_host *host)
 	dev_printk(KERN_INFO, &pdev->dev,
 		"flags: "
 		"%s%s%s%s%s%s%s"
-		"%s%s%s%s%s%s%s\n"
+		"%s%s%s%s%s%s%s"
+		"%s\n"
 		,
 
 		cap & (1 << 31) ? "64bit " : "",
@@ -2195,7 +2323,8 @@ static void ahci_print_info(struct ata_host *host)
 		cap & (1 << 17) ? "pmp " : "",
 		cap & (1 << 15) ? "pio " : "",
 		cap & (1 << 14) ? "slum " : "",
-		cap & (1 << 13) ? "part " : ""
+		cap & (1 << 13) ? "part " : "",
+		cap & (1 << 6) ? "ems ": ""
 		);
 }
 
@@ -2331,6 +2460,27 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	ahci_init_controller(host);
 	ahci_print_info(host);
 
+	if (ahci_em_messages && (hpriv->cap & HOST_CAP_EMS)) {
+		u8 messages;
+		void __iomem *mmio = host->iomap[AHCI_PCI_BAR];
+		u32 em_loc = readl(mmio + HOST_EM_LOC);
+		u32 em_ctl = readl(mmio + HOST_EM_CTL);
+
+		messages = (em_ctl & 0x000f0000) >> 16;
+
+		/* we only support LED message type right now */
+		if ((messages & 0x01) && (ahci_em_messages == 1)) {
+			/* store em_loc */
+			hpriv->em_loc = ((em_loc >> 16) * 4);
+
+			/* reset the LEDs */
+			ahci_reset_em(host);
+
+			/* modify sht to add led sysfs files */
+			ahci_sht.sdev_attrs = ahci_em_led_attrs;
+		}
+	}
+
 	pci_set_master(pdev);
 	return ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
 				 &ahci_sht);
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index fad236d..a49dc19 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -55,7 +55,7 @@ typedef unsigned int (*ata_xlat_func_t)(struct ata_queued_cmd *qc);
 
 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,
+struct ata_device *ata_scsi_find_dev(struct ata_port *ap,
 					    const struct scsi_device *scsidev);
 static int ata_scsi_user_scan(struct Scsi_Host *shost, unsigned int channel,
 			      unsigned int id, unsigned int lun);
@@ -2593,7 +2593,7 @@ static int ata_scsi_dev_enabled(struct ata_device *dev)
  *	RETURNS:
  *	Associated ATA device, or %NULL if not found.
  */
-static struct ata_device *
+struct ata_device *
 ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device *scsidev)
 {
 	struct ata_device *dev = __ata_scsi_find_dev(ap, scsidev);
@@ -2603,6 +2603,7 @@ ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device *scsidev)
 
 	return dev;
 }
+EXPORT_SYMBOL_GPL(ata_scsi_find_dev);
 
 /*
  *	ata_scsi_map_proto - Map pass-thru protocol value to taskfile value.
diff --git a/include/linux/libata.h b/include/linux/libata.h
index ef52a07..1ccbd83 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -900,6 +900,8 @@ extern int ata_scsi_slave_config(struct scsi_device *sdev);
 extern void ata_scsi_slave_destroy(struct scsi_device *sdev);
 extern int ata_scsi_change_queue_depth(struct scsi_device *sdev,
 				       int queue_depth);
+struct ata_device *ata_scsi_find_dev(struct ata_port *ap,
+				      const struct scsi_device *scsidev);
 extern struct ata_device *ata_dev_pair(struct ata_device *adev);
 extern int ata_do_set_mode(struct ata_link *link, struct ata_device **r_failed_dev);
 extern u8 ata_irq_on(struct ata_port *ap);
-- 
1.5.3.4

Re: [patch] ata: ahci: Enclosure Management via LED rev2

[Kristen Carlson Accardi]

Enclosure Management via LED

This patch implements Enclosure Management via the LED protocol as specified
in AHCI specification.

Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
---
This revision makes the change to the comment requested by Mark Lord,
fixes some bugs in the bit shifting for writing the new led state,
and implements a show function so that led status can be read as
well as written.

 drivers/ata/ahci.c        |  184 +++++++++++++++++++++++++++++++++++++++++++++-
 drivers/ata/libata-scsi.c |    5 -
 include/linux/libata.h    |    2 
 3 files changed, 187 insertions(+), 4 deletions(-)

Index: 2.6-git/drivers/ata/ahci.c
===================================================================
--- 2.6-git.orig/drivers/ata/ahci.c	2007-11-30 12:04:12.000000000 -0800
+++ 2.6-git/drivers/ata/ahci.c	2007-11-30 18:02:19.000000000 -0800
@@ -44,6 +44,7 @@
 #include <linux/dmi.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
 #include <linux/libata.h>
 
 #define DRV_NAME	"ahci"
@@ -92,6 +93,8 @@ enum {
 	HOST_IRQ_STAT		= 0x08, /* interrupt status */
 	HOST_PORTS_IMPL		= 0x0c, /* bitmap of implemented ports */
 	HOST_VERSION		= 0x10, /* AHCI spec. version compliancy */
+	HOST_EM_LOC		= 0x1c, /* Enclosure Management location */
+	HOST_EM_CTL		= 0x20, /* Enclosure Management Control */
 
 	/* HOST_CTL bits */
 	HOST_RESET		= (1 << 0),  /* reset controller; self-clear */
@@ -99,6 +102,7 @@ enum {
 	HOST_AHCI_EN		= (1 << 31), /* AHCI enabled */
 
 	/* HOST_CAP bits */
+	HOST_CAP_EMS		= (1 << 6),  /* Enclosure Management support */
 	HOST_CAP_SSC		= (1 << 14), /* Slumber capable */
 	HOST_CAP_PMP		= (1 << 17), /* Port Multiplier support */
 	HOST_CAP_CLO		= (1 << 24), /* Command List Override support */
@@ -193,6 +197,10 @@ enum {
 					  ATA_FLAG_ACPI_SATA | ATA_FLAG_AN |
 					  ATA_FLAG_IPM,
 	AHCI_LFLAG_COMMON		= ATA_LFLAG_SKIP_D2H_BSY,
+
+	/* em_ctl bits */
+	EM_CTL_RST			= (1 << 9), /* Reset */
+	EM_CTL_TM			= (1 << 8), /* Transmit Message */
 };
 
 struct ahci_cmd_hdr {
@@ -216,6 +224,7 @@ struct ahci_host_priv {
 	u32			port_map;	/* port map to use */
 	u32			saved_cap;	/* saved initial cap */
 	u32			saved_port_map;	/* saved initial port_map */
+	u32 			em_loc; /* enclosure management location */
 };
 
 struct ahci_port_priv {
@@ -231,6 +240,7 @@ struct ahci_port_priv {
 	unsigned int		ncq_saw_dmas:1;
 	unsigned int		ncq_saw_sdb:1;
 	u32 			intr_mask;	/* interrupts to enable */
+	u16			led_state;	/* saved current led state */
 };
 
 static int ahci_scr_read(struct ata_port *ap, unsigned int sc_reg, u32 *val);
@@ -572,6 +582,11 @@ static struct pci_driver ahci_pci_driver
 #endif
 };
 
+static int ahci_em_messages = 1;
+module_param(ahci_em_messages, int, 0444);
+/* add other LED protocol types when they become supported */
+MODULE_PARM_DESC(ahci_em_messages,
+	"Set AHCI Enclosure Management Message type (0 = disabled, 1 = LED");
 
 static inline int ahci_nr_ports(u32 cap)
 {
@@ -1079,6 +1094,148 @@ static int ahci_reset_controller(struct 
 	return 0;
 }
 
+/****** LED Enclosure Management routines ********/
+static int ahci_reset_em(struct ata_host *host)
+{
+	void __iomem *mmio = host->iomap[AHCI_PCI_BAR];
+	u32 em_ctl;
+
+	em_ctl = readl(mmio + HOST_EM_CTL);
+	if ((em_ctl & EM_CTL_TM) || (em_ctl & EM_CTL_RST))
+		return -EINVAL;
+
+	writel(em_ctl | EM_CTL_RST, mmio + HOST_EM_CTL);
+	return 0;
+}
+
+static int ahci_transmit_led_message(struct ata_port *ap, int led_num,
+			int state)
+{
+	struct ahci_host_priv *hpriv = ap->host->private_data;
+	void __iomem *mmio = ap->host->iomap[AHCI_PCI_BAR];
+	struct ahci_port_priv *pp = ap->private_data;
+	u32 em_ctl;
+	u32 message[] = {0, 0};
+	unsigned int flags;
+
+	spin_lock_irqsave(ap->lock, flags);
+
+	/*
+	 * if we are still busy transmitting a previous message,
+	 * do not allow
+	 */
+	em_ctl = readl(mmio + HOST_EM_CTL);
+	if (em_ctl & EM_CTL_TM) {
+		spin_unlock_irqrestore(ap->lock, flags);
+		return -EINVAL;
+	}
+
+	/*
+	 * create message header - this is all zero except for
+	 * the message size, which is 4 bytes.
+	 */
+	message[0] |= (4 << 8);
+
+	pp->led_state &= ~(7 << (3*led_num));
+
+	/*
+	 * create the actual message
+	 * This does not support Port Multiplier at this time
+	 * due to lack of hardware for testing
+	 * so the PM field is always zero.
+	 */
+	message[1] = (ap->port_no | (pp->led_state << 16));
+
+	/* LED bit locations are determined by the led_num */
+	message[1] |= (state << (16 + (3*led_num)));
+
+	/* write message to EM_LOC */
+	writel(message[0], mmio + hpriv->em_loc);
+	writel(message[1], mmio + hpriv->em_loc+4);
+
+	/* save off new led state */
+	pp->led_state = ((message[1] >> 16) & 0x01ff);
+
+	/*
+	 * tell hardware to transmit the message
+	 */
+	writel(em_ctl | EM_CTL_TM, mmio + HOST_EM_CTL);
+
+	spin_unlock_irqrestore(ap->lock, flags);
+	return 0;
+}
+
+static int ahci_led_show(struct device *dev, char *buf, int num)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct ata_port *ap = ata_shost_to_port(sdev->host);
+	struct ata_device *atadev = ata_scsi_find_dev(ap, sdev);
+	struct ahci_port_priv *pp = ap->private_data;
+
+	if (!atadev || !ata_dev_enabled(atadev))
+		return -EINVAL;
+
+	return sprintf(buf, "%d\n",
+		((pp->led_state & (7 << (3*num))) >> 3*num));
+}
+
+static int ahci_led_store(struct device *dev, const char *buf, int num)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct ata_port *ap = ata_shost_to_port(sdev->host);
+	struct ata_device *atadev = ata_scsi_find_dev(ap, sdev);
+	int state;
+
+	if (!atadev || !ata_dev_enabled(atadev))
+		return -EINVAL;
+
+	state = simple_strtoul(buf, NULL, 0);
+	if (state != 0 && state != 1)
+		return -EINVAL;
+
+	return ahci_transmit_led_message(ap, num, state);
+}
+
+static ssize_t ahci_led_locate_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	return ahci_led_show(dev, buf, 1);
+}
+
+static ssize_t ahci_led_locate_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	int rc = ahci_led_store(dev, buf, 1);
+	if (!rc)
+		return count;
+	return rc;
+}
+static DEVICE_ATTR(locate, S_IWUSR | S_IRUGO, ahci_led_locate_show,
+			ahci_led_locate_store);
+
+static ssize_t ahci_led_fault_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	return ahci_led_show(dev, buf, 2);
+}
+
+static ssize_t ahci_led_fault_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	int rc = ahci_led_store(dev, buf, 2);
+	if (!rc)
+		return count;
+	return rc;
+}
+static DEVICE_ATTR(fault, S_IWUSR | S_IRUGO, ahci_led_fault_show,
+			ahci_led_fault_store);
+
+static struct device_attribute *ahci_em_led_attrs[] = {
+	&dev_attr_locate,
+	&dev_attr_fault,
+	NULL
+};
+
 static void ahci_port_init(struct pci_dev *pdev, struct ata_port *ap,
 			   int port_no, void __iomem *mmio,
 			   void __iomem *port_mmio)
@@ -2175,7 +2332,8 @@ static void ahci_print_info(struct ata_h
 	dev_printk(KERN_INFO, &pdev->dev,
 		"flags: "
 		"%s%s%s%s%s%s%s"
-		"%s%s%s%s%s%s%s\n"
+		"%s%s%s%s%s%s%s"
+		"%s\n"
 		,
 
 		cap & (1 << 31) ? "64bit " : "",
@@ -2192,7 +2350,8 @@ static void ahci_print_info(struct ata_h
 		cap & (1 << 17) ? "pmp " : "",
 		cap & (1 << 15) ? "pio " : "",
 		cap & (1 << 14) ? "slum " : "",
-		cap & (1 << 13) ? "part " : ""
+		cap & (1 << 13) ? "part " : "",
+		cap & (1 << 6) ? "ems ": ""
 		);
 }
 
@@ -2328,6 +2487,27 @@ static int ahci_init_one(struct pci_dev 
 	ahci_init_controller(host);
 	ahci_print_info(host);
 
+	if (ahci_em_messages && (hpriv->cap & HOST_CAP_EMS)) {
+		u8 messages;
+		void __iomem *mmio = host->iomap[AHCI_PCI_BAR];
+		u32 em_loc = readl(mmio + HOST_EM_LOC);
+		u32 em_ctl = readl(mmio + HOST_EM_CTL);
+
+		messages = (em_ctl & 0x000f0000) >> 16;
+
+		/* we only support LED message type right now */
+		if ((messages & 0x01) && (ahci_em_messages == 1)) {
+			/* store em_loc */
+			hpriv->em_loc = ((em_loc >> 16) * 4);
+
+			/* reset the LEDs */
+			ahci_reset_em(host);
+
+			/* modify sht to add led sysfs files */
+			ahci_sht.sdev_attrs = ahci_em_led_attrs;
+		}
+	}
+
 	pci_set_master(pdev);
 	return ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
 				 &ahci_sht);
Index: 2.6-git/drivers/ata/libata-scsi.c
===================================================================
--- 2.6-git.orig/drivers/ata/libata-scsi.c	2007-11-30 12:04:21.000000000 -0800
+++ 2.6-git/drivers/ata/libata-scsi.c	2007-11-30 15:31:12.000000000 -0800
@@ -55,7 +55,7 @@ typedef unsigned int (*ata_xlat_func_t)(
 
 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,
+struct ata_device *ata_scsi_find_dev(struct ata_port *ap,
 					    const struct scsi_device *scsidev);
 static int ata_scsi_user_scan(struct Scsi_Host *shost, unsigned int channel,
 			      unsigned int id, unsigned int lun);
@@ -2622,7 +2622,7 @@ static int ata_scsi_dev_enabled(struct a
  *	RETURNS:
  *	Associated ATA device, or %NULL if not found.
  */
-static struct ata_device *
+struct ata_device *
 ata_scsi_find_dev(struct ata_port *ap, const struct scsi_device *scsidev)
 {
 	struct ata_device *dev = __ata_scsi_find_dev(ap, scsidev);
@@ -2632,6 +2632,7 @@ ata_scsi_find_dev(struct ata_port *ap, c
 
 	return dev;
 }
+EXPORT_SYMBOL_GPL(ata_scsi_find_dev);
 
 /*
  *	ata_scsi_map_proto - Map pass-thru protocol value to taskfile value.
Index: 2.6-git/include/linux/libata.h
===================================================================
--- 2.6-git.orig/include/linux/libata.h	2007-11-30 12:04:21.000000000 -0800
+++ 2.6-git/include/linux/libata.h	2007-11-30 15:31:12.000000000 -0800
@@ -900,6 +900,8 @@ extern int ata_scsi_slave_config(struct 
 extern void ata_scsi_slave_destroy(struct scsi_device *sdev);
 extern int ata_scsi_change_queue_depth(struct scsi_device *sdev,
 				       int queue_depth);
+struct ata_device *ata_scsi_find_dev(struct ata_port *ap,
+				      const struct scsi_device *scsidev);
 extern struct ata_device *ata_dev_pair(struct ata_device *adev);
 extern int ata_do_set_mode(struct ata_link *link, struct ata_device **r_failed_dev);
 extern u8 ata_irq_on(struct ata_port *ap);

Re: [patch] ata: ahci: Enclosure Management via LED rev2

[Jeff Garzik]

Kristen Carlson Accardi wrote:
> Enclosure Management via LED
> 
> This patch implements Enclosure Management via the LED protocol as specified
> in AHCI specification.
> 
> Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
> ---
> This revision makes the change to the comment requested by Mark Lord,
> fixes some bugs in the bit shifting for writing the new led state,
> and implements a show function so that led status can be read as
> well as written.

Overall looks pretty good, from a technical review perspective.

Two worries:

1) exporting ata_scsi_find_dev(), and assuming a scsi device is 
attached.  the latter can be fixed by a !NULL check (and should be), but 
its a bit of a layering violation since long term we want to make the 
SCSI simulator optional for all ATA devices.

2) vaguely related to #1, I'm not so sure the attributes should be 
implemented directly in ahci.  if this __or something like it__ appears 
on non-Intel hardware, the code should be somewhere more generic.

Re: [patch] ata: ahci: Enclosure Management via LED rev2

[Kristen Carlson Accardi]

On Sat, 01 Dec 2007 18:28:54 -0500
Jeff Garzik <jeff@garzik.org> wrote:

> Kristen Carlson Accardi wrote:
> > Enclosure Management via LED
> > 
> > This patch implements Enclosure Management via the LED protocol as
> > specified in AHCI specification.
> > 
> > Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
> > ---
> > This revision makes the change to the comment requested by Mark
> > Lord, fixes some bugs in the bit shifting for writing the new led
> > state, and implements a show function so that led status can be
> > read as well as written.
> 
> Overall looks pretty good, from a technical review perspective.
> 
> Two worries:
> 
> 1) exporting ata_scsi_find_dev(), and assuming a scsi device is 
> attached.  the latter can be fixed by a !NULL check (and should be),
> but its a bit of a layering violation since long term we want to make
> the SCSI simulator optional for all ATA devices.
> 
> 2) vaguely related to #1, I'm not so sure the attributes should be 
> implemented directly in ahci.  if this __or something like it__
> appears on non-Intel hardware, the code should be somewhere more
> generic.
> 

When I first started developing this patch, I did have a more generic
approach - It adds lots of complexity that isn't needed for this simple
protocol, and one of the problems I encountered was that for different
EM protocols, you'd probably want to have a different set of attributes
defined.  Also, even using the same protocol, you may have hardware
that supports more attributes.  For example, in the case of this LED
protocol, some implementations may support the Activity LED (software
controlled), and some may not.  For protocols like SGPIO, they have a
lot of attributes defined by the spec, but I'm guessing hardware may
not support all of them.  When I tried to abstract hardware and
protocol away and make some kind of generic enclosure management
framework, it turned into this big ordeal.  So, I can keep going along
those lines, but to me it started to seem silly since I had no other
hardware that I knew of that was going to be helped by all this.  I
thought maybe the right thing to do was to keep it simple and then wait
for other the hardware to appear.