So far the driver unconditionally delays 10ms when en/disabling the controller and still return 0 if 10ms times out. In fact, spec defines a timeout value in the CAP register that is the worst case time that host software shall wait for the controller to become ready.
Signed-off-by: Bin Meng bmeng.cn@gmail.com ---
drivers/nvme/nvme.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/nvme/nvme.c b/drivers/nvme/nvme.c index d92273e..8867977 100644 --- a/drivers/nvme/nvme.c +++ b/drivers/nvme/nvme.c @@ -47,11 +47,19 @@ struct nvme_queue { static int nvme_wait_ready(struct nvme_dev *dev, bool enabled) { u32 bit = enabled ? NVME_CSTS_RDY : 0; + int timeout; + ulong start;
- while ((readl(&dev->bar->csts) & NVME_CSTS_RDY) != bit) - udelay(10000); + /* Timeout field in the CAP register is in 500 millisecond units */ + timeout = NVME_CAP_TIMEOUT(dev->cap) * 500;
- return 0; + start = get_timer(0); + while (get_timer(start) < timeout) { + if ((readl(&dev->bar->csts) & NVME_CSTS_RDY) == bit) + return 0; + } + + return -ETIME; }
static int nvme_setup_prps(struct nvme_dev *dev, u64 *prp2,