When powering up, the SATA controller may fail to mount the HDD. The SATA
controller will lock up, preventing it from negotiating to a lower speed or
transmitting data. Root cause is power supply noise creating resonance at 6 Ghz
and 3 GHz frequencies, which causes instability in the Clock-Data Recovery
(CDR) frontend module, resulting in false acquisition of the clock at SATA
6G/3G speeds.
The SATA controller may fail to mount the HDD and lock up, requiring a power
cycle. Broadcom chips suspected of being susceptible to this issue include
BCM7445, BCM7439, and BCM7366.
The Kernel implements an error recovery mechanism that resets the SATA PHY and
digital controller when the controller locks up. During this error recovery
process, typically there is less activity on the board and Broadcom STB chip,
so that the power supply is less noisy, thus allowing the SATA controller to
lock correctly.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We are doing a blind write to SATA_TOP_CTRL_BUS_CTRL to set the system
endian, but in doing so, we are also overwriting other bits, such as the
SATA_SCB_BURST_SIZE and SATA_FIFO_SIZE bits, which impact performance.
Do a read/modify/write so we keep the default values.
While we are at it, we also greatly simplify the logic and just leave
the NSP specific bit settings, instead of having a completely different
sequence.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit makes use of the AHCI_HFLAG_YES_ALPM flag to prevent
the driver from writing to the read-only Host Capability register.
It also sets the AHCI_HFLAG_NO_WRITE_TO_RO flag to prevent the AHCI
library from writing to read-only registers.
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
