• Alexander Bondar's avatar
    iwlwifi: pcie: enable LP XTAL to reduce power consumption · a812cba9
    Alexander Bondar authored
    1. Enable LP XTAL to avoid HW bug where device may consume much
    power if FW is not loaded after device reset. LP XTAL is
    disabled by default after device HW reset. Configure device's
    "persistence" mode to avoid resetting XTAL again when SHRD_HW_RST
    occurs in S3.
    
    2. Add methods to access SHR (shared block memory space) directly from PCI
    bus w/o need to power up MAC HW.
    
    Shared internal registers (e.g. SHR_APMG_GP1, SHR_APMG_XTAL_CFG)can be
    accessed directly from PCI bus through SHR arbiter even when MAC HW is
    powered down. This is possible due to indirect read/write via
    HEEP_CTRL_WRD_PCIEX_CTRL (0xEC) and HEEP_CTRL_WRD_PCIEX_DATA (0xF4)
    registers.
    
    Use iwl_write32()/iwl_read32() family to access these registers. The MAC HW
    need not be powered up so no "grab inc access" is required.
    
    For example, to read from SHR_APMG_GP1 register (0x1DC),
    first, write to the control register:
    HEEP_CTRL_WRD_PCIEX_CTRL[15:0] = 0x1DC (offset of the SHR_APMG_GP1 register)
    HEEP_CTRL_WRD_PCIEX_CTRL[29:28] = 2 (read access)
    second, read from the data register HEEP_CTRL_WRD_PCIEX_DATA[31:0].
    
    To write the register, first, write to the data register
    HEEP_CTRL_WRD_PCIEX_DATA[31:0] and then:
    HEEP_CTRL_WRD_PCIEX_CTRL[15:0] = 0x1DC (offset of the SHR_APMG_GP1 register)
    HEEP_CTRL_WRD_PCIEX_CTRL[29:28] = 3 (write access)
    Signed-off-by: default avatarAlexander Bondar <alexander.bondar@intel.com>
    Signed-off-by: default avatarEmmanuel Grumbach <emmanuel.grumbach@intel.com>
    a812cba9
iwl-io.h 2.95 KB