linux/drivers/ata/libata.h

262 lines
10 KiB

libata: implement slave_link Explanation taken from the comment of ata_slave_link_init(). In libata, a port contains links and a link contains devices. There is single host link but if a PMP is attached to it, there can be multiple fan-out links. On SATA, there's usually a single device connected to a link but PATA and SATA controllers emulating TF based interface can have two - master and slave. However, there are a few controllers which don't fit into this abstraction too well - SATA controllers which emulate TF interface with both master and slave devices but also have separate SCR register sets for each device. These controllers need separate links for physical link handling (e.g. onlineness, link speed) but should be treated like a traditional M/S controller for everything else (e.g. command issue, softreset). slave_link is libata's way of handling this class of controllers without impacting core layer too much. For anything other than physical link handling, the default host link is used for both master and slave. For physical link handling, separate @ap->slave_link is used. All dirty details are implemented inside libata core layer. From LLD's POV, the only difference is that prereset, hardreset and postreset are called once more for the slave link, so the reset sequence looks like the following. prereset(M) -> prereset(S) -> hardreset(M) -> hardreset(S) -> softreset(M) -> postreset(M) -> postreset(S) Note that softreset is called only for the master. Softreset resets both M/S by definition, so SRST on master should handle both (the standard method will work just fine). As slave_link excludes PMP support and only code paths which deal with the attributes of physical link are affected, all the changes are localized to libata.h, libata-core.c and libata-eh.c. * ata_is_host_link() updated so that slave_link is considered as host link too. * iterator extended to iterate over the slave_link when using the underbarred version. * force param handling updated such that devno 16 is mapped to the slave link/device. * ata_link_on/offline() updated to return the combined result from master and slave link. ata_phys_link_on/offline() are the direct versions. * EH autopsy and report are performed separately for master slave links. Reset is udpated to implement the above described reset sequence. Except for reset update, most changes are minor, many of them just modifying dev->link to ata_dev_phys_link(dev) or using phys online test instead. After this update, LLDs can take full advantage of per-dev SCR registers by simply turning on slave link. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-07-31 17:02:43 +09:00
ata: libata-scsi: Disable scsi device manage_system_start_stop The introduction of a device link to create a consumer/supplier relationship between the scsi device of an ATA device and the ATA port of that ATA device fixes the ordering of system suspend and resume operations. For suspend, the scsi device is suspended first and the ata port after it. This is fine as this allows the synchronize cache and START STOP UNIT commands issued by the scsi disk driver to be executed before the ata port is disabled. For resume operations, the ata port is resumed first, followed by the scsi device. This allows having the request queue of the scsi device to be unfrozen after the ata port resume is scheduled in EH, thus avoiding to see new requests prematurely issued to the ATA device. Since libata sets manage_system_start_stop to 1, the scsi disk resume operation also results in issuing a START STOP UNIT command to the device being resumed so that the device exits standby power mode. However, restoring the ATA device to the active power mode must be synchronized with libata EH processing of the port resume operation to avoid either 1) seeing the start stop unit command being received too early when the port is not yet resumed and ready to accept commands, or after the port resume process issues commands such as IDENTIFY to revalidate the device. In this last case, the risk is that the device revalidation fails with timeout errors as the drive is still spun down. Commit 0a8589055936 ("ata,scsi: do not issue START STOP UNIT on resume") disabled issuing the START STOP UNIT command to avoid issues with it. But this is incorrect as transitioning a device to the active power mode from the standby power mode set on suspend requires a media access command. The IDENTIFY, READ LOG and SET FEATURES commands executed in libata EH context triggered by the ata port resume operation may thus fail. Fix these synchronization issues is by handling a device power mode transitions for system suspend and resume directly in libata EH context, without relying on the scsi disk driver management triggered with the manage_system_start_stop flag. To do this, the following libata helper functions are introduced: 1) ata_dev_power_set_standby(): This function issues a STANDBY IMMEDIATE command to transitiom a device to the standby power mode. For HDDs, this spins down the disks. This function applies only to ATA and ZAC devices and does nothing otherwise. This function also does nothing for devices that have the ATA_FLAG_NO_POWEROFF_SPINDOWN or ATA_FLAG_NO_HIBERNATE_SPINDOWN flag set. For suspend, call ata_dev_power_set_standby() in ata_eh_handle_port_suspend() before the port is disabled and frozen. ata_eh_unload() is also modified to transition all enabled devices to the standby power mode when the system is shutdown or devices removed. 2) ata_dev_power_set_active() and This function applies to ATA or ZAC devices and issues a VERIFY command for 1 sector at LBA 0 to transition the device to the active power mode. For HDDs, since this function will complete only once the disk spin up. Its execution uses the same timeouts as for reset, to give the drive enough time to complete spinup without triggering a command timeout. For resume, call ata_dev_power_set_active() in ata_eh_revalidate_and_attach() after the port has been enabled and before any other command is issued to the device. With these changes, the manage_system_start_stop and no_start_on_resume scsi device flags do not need to be set in ata_scsi_dev_config(). The flag manage_runtime_start_stop is still set to allow the sd driver to spinup/spindown a disk through the sd runtime operations. Fixes: 0a8589055936 ("ata,scsi: do not issue START STOP UNIT on resume") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
2023-08-26 09:43:39 +09:00
libata: implement slave_link Explanation taken from the comment of ata_slave_link_init(). In libata, a port contains links and a link contains devices. There is single host link but if a PMP is attached to it, there can be multiple fan-out links. On SATA, there's usually a single device connected to a link but PATA and SATA controllers emulating TF based interface can have two - master and slave. However, there are a few controllers which don't fit into this abstraction too well - SATA controllers which emulate TF interface with both master and slave devices but also have separate SCR register sets for each device. These controllers need separate links for physical link handling (e.g. onlineness, link speed) but should be treated like a traditional M/S controller for everything else (e.g. command issue, softreset). slave_link is libata's way of handling this class of controllers without impacting core layer too much. For anything other than physical link handling, the default host link is used for both master and slave. For physical link handling, separate @ap->slave_link is used. All dirty details are implemented inside libata core layer. From LLD's POV, the only difference is that prereset, hardreset and postreset are called once more for the slave link, so the reset sequence looks like the following. prereset(M) -> prereset(S) -> hardreset(M) -> hardreset(S) -> softreset(M) -> postreset(M) -> postreset(S) Note that softreset is called only for the master. Softreset resets both M/S by definition, so SRST on master should handle both (the standard method will work just fine). As slave_link excludes PMP support and only code paths which deal with the attributes of physical link are affected, all the changes are localized to libata.h, libata-core.c and libata-eh.c. * ata_is_host_link() updated so that slave_link is considered as host link too. * iterator extended to iterate over the slave_link when using the underbarred version. * force param handling updated such that devno 16 is mapped to the slave link/device. * ata_link_on/offline() updated to return the combined result from master and slave link. ata_phys_link_on/offline() are the direct versions. * EH autopsy and report are performed separately for master slave links. Reset is udpated to implement the above described reset sequence. Except for reset update, most changes are minor, many of them just modifying dev->link to ata_dev_phys_link(dev) or using phys online test instead. After this update, LLDs can take full advantage of per-dev SCR registers by simply turning on slave link. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-07-31 17:02:43 +09:00
ata: libata: Improve CDL resource management The ncq_sense_buf buffer field of struct ata_port is allocated and used only for devices that support the Command Duration Limits (CDL) feature. However, the cdl buffer of struct ata_device, which is used to cache the command duration limits log page for devices supporting CDL is always allocated as part of struct ata_device, which is wasteful of memory for devices that do not support this feature. Clean this up by defining both buffers as part of the new ata_cdl structure and allocating this structure only for devices that support the CDL feature. This new structure is attached to struct ata_device using the cdl pointer. The functions ata_dev_init_cdl_resources() and ata_dev_cleanup_cdl_resources() are defined to manage this new structure allocation, initialization and freeing when a port is removed or a device disabled. ata_dev_init_cdl_resources() is called from ata_dev_config_cdl() only for devices that support CDL. ata_dev_cleanup_cdl_resources() is called from ata_dev_free_resources() to free the ata_cdl structure when a device is being disabled by EH. Note that the name of the former cdl log buffer of struct ata_device is changed to desc_log_buf to make it clearer that it is a buffer for the limit descriptors log page. This change reduces the size of struct ata_device, thus reducing memory usage for ATA devices that do not support the CDL feature. Signed-off-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Niklas Cassel <cassel@kernel.org>
2024-07-17 17:55:31 +09:00
2006-11-22 14:55:48 +00:00
libata: implement cross-port EH exclusion In libata, the non-EH code paths should always take and release ap->lock explicitly when accessing hardware or shared data structures. However, once EH is active, it's assumed that the port is owned by EH and EH methods don't explicitly take ap->lock unless race from irq handler or other code paths are expected. However, libata EH didn't guarantee exclusion among EHs for ports of the same host. IOW, multiple EHs may execute in parallel on multiple ports of the same controller. In many cases, especially in SATA, the ports are completely independent of each other and this doesn't cause problems; however, there are cases where different ports share the same resource, which lead to obscure timing related bugs such as the one fixed by commit 213373cf (ata_piix: fix locking around SIDPR access). This patch implements exclusion among EHs of the same host. When EH begins, it acquires per-host EH ownership by calling ata_eh_acquire(). When EH finishes, the ownership is released by calling ata_eh_release(). EH ownership is also released whenever the EH thread goes to sleep from ata_msleep() or explicitly and reacquired after waking up. This ensures that while EH is actively accessing the hardware, it has exclusive access to it while allowing EHs to interleave and progress in parallel as they hit waiting stages, which dominate the time spent in EH. This achieves cross-port EH exclusion without pervasive and fragile changes while still allowing parallel EH for the most part. This was first reported by yuanding02@gmail.com more than three years ago in the following bugzilla. :-) https://bugzilla.kernel.org/show_bug.cgi?id=8223 Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Reported-by: yuanding02@gmail.com Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2010-09-06 17:57:14 +02:00
libata: check zero power ready status for ZPODD Per the Mount Fuji spec, the ODD is considered zero power ready when: - For slot type ODD, no media inside; - For tray type ODD, no media inside and tray closed. The information can be retrieved by either the returned information of command GET_EVENT_STATUS_NOTIFICATION(the command is used to poll for media event) or sense code. The information provided by the media status byte is not accurate, it is possible that after a new disc is just inserted, the status byte still returns media not present. So this information can not be used as the deciding factor, we use sense code to decide if zpready status is true. When we first sensed the ODD in the zero power ready state, the zp_sampled will be set and timestamp will be recoreded. And after ODD stayed in this state for some pre-defined period, the ODD is considered as power off ready and the zp_ready flag will be set. The zp_ready flag serves as the deciding factor other code will use to see if power off is OK for the ODD. The Mount Fuji spec suggests a delay should be used here, to avoid the case user ejects the ODD and then instantly inserts a new one again, so that we can avoid a power transition. And some ODDs may be slow to place its head to the home position after disc is ejected, so a delay here is generally a good idea. And the delay time can be changed via the module param zpodd_poweroff_delay. The zero power ready status check is performed in the ata port's runtime suspend code path, when port is not frozen yet, as we need to issue some IOs to the ODD. Signed-off-by: Aaron Lu <aaron.lu@intel.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2013-01-15 17:21:00 +08:00
libata: check zero power ready status for ZPODD Per the Mount Fuji spec, the ODD is considered zero power ready when: - For slot type ODD, no media inside; - For tray type ODD, no media inside and tray closed. The information can be retrieved by either the returned information of command GET_EVENT_STATUS_NOTIFICATION(the command is used to poll for media event) or sense code. The information provided by the media status byte is not accurate, it is possible that after a new disc is just inserted, the status byte still returns media not present. So this information can not be used as the deciding factor, we use sense code to decide if zpready status is true. When we first sensed the ODD in the zero power ready state, the zp_sampled will be set and timestamp will be recoreded. And after ODD stayed in this state for some pre-defined period, the ODD is considered as power off ready and the zp_ready flag will be set. The zp_ready flag serves as the deciding factor other code will use to see if power off is OK for the ODD. The Mount Fuji spec suggests a delay should be used here, to avoid the case user ejects the ODD and then instantly inserts a new one again, so that we can avoid a power transition. And some ODDs may be slow to place its head to the home position after disc is ejected, so a delay here is generally a good idea. And the delay time can be changed via the module param zpodd_poweroff_delay. The zero power ready status check is performed in the ata port's runtime suspend code path, when port is not frozen yet, as we need to issue some IOs to the ODD. Signed-off-by: Aaron Lu <aaron.lu@intel.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2013-01-15 17:21:00 +08:00
libata: check zero power ready status for ZPODD Per the Mount Fuji spec, the ODD is considered zero power ready when: - For slot type ODD, no media inside; - For tray type ODD, no media inside and tray closed. The information can be retrieved by either the returned information of command GET_EVENT_STATUS_NOTIFICATION(the command is used to poll for media event) or sense code. The information provided by the media status byte is not accurate, it is possible that after a new disc is just inserted, the status byte still returns media not present. So this information can not be used as the deciding factor, we use sense code to decide if zpready status is true. When we first sensed the ODD in the zero power ready state, the zp_sampled will be set and timestamp will be recoreded. And after ODD stayed in this state for some pre-defined period, the ODD is considered as power off ready and the zp_ready flag will be set. The zp_ready flag serves as the deciding factor other code will use to see if power off is OK for the ODD. The Mount Fuji spec suggests a delay should be used here, to avoid the case user ejects the ODD and then instantly inserts a new one again, so that we can avoid a power transition. And some ODDs may be slow to place its head to the home position after disc is ejected, so a delay here is generally a good idea. And the delay time can be changed via the module param zpodd_poweroff_delay. The zero power ready status check is performed in the ata port's runtime suspend code path, when port is not frozen yet, as we need to issue some IOs to the ODD. Signed-off-by: Aaron Lu <aaron.lu@intel.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2013-01-15 17:21:00 +08:00