lkml.org 
[lkml]   [2017]   [Jun]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH v4 20/28] ARM: owl: Implement CPU enable-method for S500
    On Tue, Jun 6, 2017 at 2:54 AM, Andreas Färber <afaerber@suse.de> wrote:
    > Allow to bring up CPU1.
    >
    > Based on LeMaker linux-actions tree.
    >
    > Signed-off-by: Andreas Färber <afaerber@suse.de>
    > ---
    > v3 -> v4: Unchanged
    >
    > v3: new
    >
    > arch/arm/mach-actions/Makefile | 3 +
    > arch/arm/mach-actions/headsmp.S | 68 ++++++++++++++++
    > arch/arm/mach-actions/platsmp.c | 166 ++++++++++++++++++++++++++++++++++++++++

    I now see build errors in linux-next:

    /git/arm-soc/arch/arm/mach-actions/platsmp.c: In function 'write_pen_release':
    /git/arm-soc/arch/arm/mach-actions/platsmp.c:39:2: error:
    'pen_release' undeclared (first use in this function); did you mean
    'seq_release'?
    pen_release = val;
    ^~~~~~~~~~~
    seq_release
    /git/arm-soc/arch/arm/mach-actions/platsmp.c:39:2: note: each
    undeclared identifier is reported only once for each function it
    appears in
    /git/arm-soc/arch/arm/mach-actions/platsmp.c: In function
    's500_wakeup_secondary':
    /git/arm-soc/arch/arm/mach-actions/platsmp.c:79:2: error: implicit
    declaration of function 'dsb_sev'
    [-Werror=implicit-function-declaration]
    dsb_sev();
    ^~~~~~~
    /git/arm-soc/arch/arm/mach-actions/platsmp.c: In function
    's500_smp_boot_secondary':
    /git/arm-soc/arch/arm/mach-actions/platsmp.c:108:7: error:
    'pen_release' undeclared (first use in this function); did you mean
    'seq_release'?


    > +static DEFINE_SPINLOCK(boot_lock);
    > +
    > +static void write_pen_release(int val)
    > +{
    > + pen_release = val;
    > + smp_wmb();
    > + __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
    > + outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
    > +}
    > +
    > +static void s500_smp_secondary_init(unsigned int cpu)
    > +{
    > + /*
    > + * let the primary processor know we're out of the
    > + * pen, then head off into the C entry point
    > + */
    > + write_pen_release(-1);
    > +
    > + spin_lock(&boot_lock);
    > + spin_unlock(&boot_lock);
    > +}
    > +
    > +void owl_secondary_startup(void);
    > +
    > +static int s500_wakeup_secondary(unsigned int cpu)
    > +{
    > + if (cpu > 3)
    > + return -EINVAL;
    > +
    > + switch (cpu) {
    > + case 2:
    > + case 3:
    > + /* CPU2/3 are power-gated */
    > + return -EINVAL;
    > + }
    > +
    > + /* wait for CPUx to run to WFE instruction */
    > + udelay(200);
    > +
    > + writel(virt_to_phys(owl_secondary_startup),
    > + timer_base_addr + OWL_CPU1_ADDR + (cpu - 1) * 4);
    > + writel(OWL_CPUx_FLAG_BOOT,
    > + timer_base_addr + OWL_CPU1_FLAG + (cpu - 1) * 4);
    > +
    > + dsb_sev();
    > + mb();
    > +
    > + return 0;
    > +}
    > +
    > +static int s500_smp_boot_secondary(unsigned int cpu, struct task_struct *idle)
    > +{
    > + unsigned long timeout;
    > + int ret;
    > +
    > + ret = s500_wakeup_secondary(cpu);
    > + if (ret)
    > + return ret;
    > +
    > + udelay(10);
    > +
    > + spin_lock(&boot_lock);
    > +
    > + /*
    > + * The secondary processor is waiting to be released from
    > + * the holding pen - release it, then wait for it to flag
    > + * that it has been released by resetting pen_release.
    > + */
    > + write_pen_release(cpu_logical_map(cpu));
    > + smp_send_reschedule(cpu);
    > +
    > + timeout = jiffies + (1 * HZ);
    > + while (time_before(jiffies, timeout)) {
    > + if (pen_release == -1)
    > + break;
    > + }
    > +
    > + writel(0, timer_base_addr + OWL_CPU1_ADDR + (cpu - 1) * 4);
    > + writel(0, timer_base_addr + OWL_CPU1_FLAG + (cpu - 1) * 4);
    > +
    > + spin_unlock(&boot_lock);
    > +
    > + return pen_release != -1 ? -ENOSYS : 0;
    > +}

    This looks more complicated than necessary. Why do you need the holding
    pen when you have a register to start up the CPU?

    Arnd

    \
     
     \ /
      Last update: 2017-06-21 10:18    [W:4.165 / U:0.524 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site