lkml.org 
[lkml]   [2011]   [Nov]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 2a/5 v2] ARM: OMAP1: select clock rate by CPU type
    * Janusz Krzysztofik <jkrzyszt@tis.icnet.pl> [111130 12:23]:
    > DPLL1 reprogramming to a different rate is actually blocked inside
    > omap1_select_table_rate(), resulting in the defalut rate of 60 MHz
    > always used instead of the one selected in .config. OTOH, in
    > omap1_defconfig we currently rely on Kconfig options for the supported
    > MHz rates in case of boards which boot with dpll1 not set correctly by
    > their boot loaders.
    > This means that before we allow for reprogramming of dpll1 rate, we
    > should prevent from incompatible clock rates being selected, otherwise
    > omap1_defconfig will stop booting on boards with imperfect boot loaders,
    > as it would always try to change to 216MHz.
    >
    > Expand omap1_rate_table with flags for different CPU types and match
    > them while selecting clock rates. The idea is stolen from current
    > omap24xx clock rate selection algorithm.
    >
    > Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
    > ---
    > Hi,
    > Since there is no response to patch 2a/5 "Remove unsafe clock values
    > from omap1_defconfig" yet, while rc4 is probably almost out:

    Well I'm still wondering what would be the absolute minimal fixe(s)
    for the -rc cycle?

    Is the problem just that currently with omap1_defconfig boards boot at
    the bootloader rate, or at the safe 60MHz unless the .config is changed?
    If so, I think that's OK for now as fixing it properly requires what
    this patch is doing.

    > If there are reasons for keeping high clock rates selected in
    > omap1_defconfig, and those reasons are more important than fixing bugs
    > which prevent some boards from working correctly under 3.2, here is an
    > alternative, low intrusive solution which should allow booting from
    > omap1_defconfig at correct speeds, selected by CPU type. If the idea is
    > acceptable, please review the CPU per clock rate selections I made,
    > since I'm not sure about their correctness, perhaps except CK_1510,
    > which is based on my own experience with Amstrad Delta. I'll fix that if
    > necessary.

    Great, this looks like pretty much what I had in mind for the next
    merge window! Just one comment below.


    > @@ -21,38 +22,52 @@ struct mpu_rate omap1_rate_table[] = {
    > * armdiv, dspdiv, dspmmu, tcdiv, perdiv, lcddiv
    > */
    > #if defined(CONFIG_OMAP_ARM_216MHZ)
    > - { 216000000, 12000000, 216000000, 0x050d, 0x2910 }, /* 1/1/2/2/2/8 */
    > + { 216000000, 12000000, 216000000, 0x050d, 0x2910, /* 1/1/2/2/2/8 */
    > + CK_16XX },
    > #endif
    > #if defined(CONFIG_OMAP_ARM_195MHZ)
    > - { 195000000, 13000000, 195000000, 0x050e, 0x2790 }, /* 1/1/2/2/4/8 */
    > + { 195000000, 13000000, 195000000, 0x050e, 0x2790, /* 1/1/2/2/4/8 */
    > + CK_7XX|CK_16XX },
    > #endif
    > #if defined(CONFIG_OMAP_ARM_192MHZ)
    ...

    We should also now be able to remove all the CONFIG_OMAP_ARM_XXXMHZ options
    too, right?

    Regards,

    Tony


    \
     
     \ /
      Last update: 2011-11-30 23:31    [from the cache]
    ©2003-2014 Jasper Spaans. hosted at Digital Ocean