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@xxxxxxxxx>
ACK, provided that you banish all mentions of "FIS34" from the patch description.
"D2H FIS" is far more understandable to the average human. Jeff - : send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
