[U-Boot-Users] 83xx, FSL_UEC reducing boot latency, printf causing crash
Russell McGuire
rmcguire at videopresence.com
Wed Dec 19 04:58:40 CET 2007
Kim,
I am getting around to helping test out this reduced latency patch.
Interesting I have found the boot cycle times are MUCH faster, however, is
it supposed to continuously restart the auto-negotiation each time a
ethernet access is performed? i.e. a new ping, or tftp download? For example
if I issue a tftp load three times in a row, the 2nd time it will tear down
the link and restart it. The third time it will crash, though I believe this
is to do with the below mentioned printf issue.
I am looking into ways to optimize this, are there any updates to the patch
before I start modifying things?
Another bug?? Not sure this is Ethernet specific but perhaps U-boot generic.
Is that if I add printf() statements throughout the uec code I get total
crashes of u-boot, i.e. bad traps that result in a back trace and board
resets.
-Russ
________________________________
> > Hi Kim
> >
> > Perhaps you can have a look at "MPC83xx Ethernet bug"
> > while you are at it?
> >
> <sigh>
>
> Hi Jocke,
>
> not completely tested yet; perhaps you can help? :
>
> Subject: [PATCH] net: reduce boot latency on QE UEC based boards
>
> actually polling for PHY autonegotiation to finish enables us to remove
> the
> paranoid (and horrid) 5 second boot prompt latency present on QE based
> boards.
>
> autonegotiation wait code shamelessly stolen from tsec driver.
>
> Signed-off-by: Kim Phillips <kim.phillips at freescale.com>
> ---
> drivers/qe/uec.c | 17 ++++-------------
> drivers/qe/uec_phy.c | 49 ++++++++++++++++++++++++++++++++++-----------
> ----
> 2 files changed, 38 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/qe/uec.c b/drivers/qe/uec.c
> index dc2765b..9bd80e7 100644
> --- a/drivers/qe/uec.c
> +++ b/drivers/qe/uec.c
> @@ -562,21 +562,12 @@ static void adjust_link(struct eth_device *dev)
> static void phy_change(struct eth_device *dev)
> {
> uec_private_t *uec = (uec_private_t *)dev->priv;
> - uec_t *uec_regs;
> - int result = 0;
> -
> - uec_regs = uec->uec_regs;
> -
> - /* Delay 5s to give the PHY a chance to change the register state */
> - udelay(5000000);
>
> /* Update the link, speed, duplex */
> - result = uec->mii_info->phyinfo->read_status(uec->mii_info);
> + uec->mii_info->phyinfo->read_status(uec->mii_info);
>
> /* Adjust the interface according to speed */
> - if ((0 == result) || (uec->mii_info->link == 0)) {
> - adjust_link(dev);
> - }
> + adjust_link(dev);
> }
>
> static int uec_set_mac_address(uec_private_t *uec, u8 *mac_addr)
> @@ -1103,6 +1094,8 @@ static int uec_init(struct eth_device* dev, bd_t
> *bd)
> uec_private_t *uec;
> int err;
>
> + phy_change(dev);
> +
> uec = (uec_private_t *)dev->priv;
>
> if (uec->the_first_run == 0) {
> @@ -1271,8 +1264,6 @@ int uec_initialize(int index)
> return err;
> }
>
> - phy_change(dev);
> -
> return 1;
> }
> #endif /* CONFIG_QE */
> diff --git a/drivers/qe/uec_phy.c b/drivers/qe/uec_phy.c
> index ca6faa6..f3382f2 100644
> --- a/drivers/qe/uec_phy.c
> +++ b/drivers/qe/uec_phy.c
> @@ -270,20 +270,41 @@ static int genmii_update_link (struct uec_mii_info
> *mii_info)
> {
> u16 status;
>
> - /* Do a fake read */
> - phy_read (mii_info, PHY_BMSR);
> -
> - /* Read link and autonegotiation status */
> - status = phy_read (mii_info, PHY_BMSR);
> - if ((status & PHY_BMSR_LS) == 0)
> - mii_info->link = 0;
> - else
> + /*
> + * Wait if the link is up, and autonegotiation is in progress
> + * (ie - we're capable and it's not done)
> + */
> + status = phy_read(mii_info, PHY_BMSR);
> + if ((status & PHY_BMSR_LS) && (status & PHY_BMSR_AUTN_ABLE)
> + && !(status & PHY_BMSR_AUTN_COMP)) {
> + int i = 0;
> +
> + puts("Waiting for PHY auto negotiation to complete");
> + while (!(status & PHY_BMSR_AUTN_COMP)) {
> + /*
> + * Timeout reached ?
> + */
> + if (i > UGETH_AN_TIMEOUT) {
> + puts(" TIMEOUT !\n");
> + mii_info->link = 0;
> + return 0;
> + }
> +
> + if ((i++ % 1000) == 0) {
> + putc('.');
> + }
> + udelay(1000); /* 1 ms */
> + status = phy_read(mii_info, PHY_BMSR);
> + }
> + puts(" done\n");
> mii_info->link = 1;
> -
> - /* If we are autonegotiating, and not done,
> - * return an error */
> - if (mii_info->autoneg && !(status & PHY_BMSR_AUTN_COMP))
> - return -EAGAIN;
> + udelay(500000); /* another 500 ms (results in faster
> booting) */
> + } else {
> + if (status & PHY_BMSR_LS)
> + mii_info->link = 1;
> + else
> + mii_info->link = 0;
> + }
>
> return 0;
> }
> @@ -397,8 +418,6 @@ static int dm9161_init (struct uec_mii_info *mii_info)
> config_genmii_advert (mii_info);
> /* Start/restart aneg */
> genmii_config_aneg (mii_info);
> - /* Delay to wait the aneg compeleted */
> - udelay (3000000);
>
> return 0;
> }
> --
> 1.5.2.2
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