• M
    mtd: rawnand: marvell: prevent timeouts on a loaded machine · a1d06e4e
    Miquel Raynal 提交于
    commit cafb56dd741e61c99709bcd2b193a9a1d36def3b upstream.
    
    marvell_nfc_wait_op() waits for completion during 'timeout_ms'
    milliseconds before throwing an error. While the logic is fine, the
    value of 'timeout_ms' is given by the core and actually correspond to
    the maximum time the NAND chip will take to complete the
    operation. Assuming there is no overhead in the propagation of the
    interrupt signal to the the NAND controller (through the Ready/Busy
    line), this delay does not take into account the latency of the
    operating system. For instance, for a page write, the delay given by
    the core is rounded up to 1ms. Hence, when the machine is over loaded,
    there is chances that this timeout will be reached.
    
    There are two ways to solve this issue that are not incompatible:
    1/ Enlarge the timeout value (if so, how much?).
    2/ Check after the waiting method if we did not miss any interrupt
    because of the OS latency (an interrupt is still pending). In this
    case, we assume the operation exited successfully.
    
    We choose the second approach that is a must in all cases, with the
    possibility to also modify the timeout value to be, e.g. at least 1
    second in all cases.
    
    Fixes: 02f26ecf ("mtd: nand: add reworked Marvell NAND controller driver")
    Cc: stable@vger.kernel.org
    Signed-off-by: NMiquel Raynal <miquel.raynal@bootlin.com>
    Reviewed-by: NBoris Brezillon <boris.brezillon@bootlin.com>
    Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
    a1d06e4e
marvell_nand.c 82.9 KB