Hi Tony and Paul,
Just a little question/warn, these kind of code may not be preempt safe:
<snip>
+/* Enables clock without considering parent dependencies or use count
+ * REVISIT: Maybe change this to use clk->enable like on omap1?
+ */
+int _omap2_clk_enable(struct clk *clk)
+{
+ u32 regval32;
+
+ if (clk->flags & (ALWAYS_ENABLED | PARENT_CONTROLS_CLOCK))
+ return 0;
+
+ if (clk->enable)
+ return clk->enable(clk);
+
+ if (unlikely(clk->enable_reg == 0)) {
+ printk(KERN_ERR "clock.c: Enable for %s without enable code\n",
+ clk->name);
+ return 0; /* REVISIT: -EINVAL */
+ }
+
+ regval32 = cm_read_reg(clk->enable_reg);
+ if (clk->flags & INVERT_ENABLE)
+ regval32 &= ~(1 << clk->enable_bit);
+ else
+ regval32 |= (1 << clk->enable_bit);
+ cm_write_reg(regval32, clk->enable_reg);
+ wmb();
+
+ omap2_clk_wait_ready(clk);
+
+ return 0;
+}
<snip>
Are these registers protected somehow? because this read followed by a write
may not be a preempt safe operation. Or this code is not designed for
CONFIG_PREEMPT?
Cheers,
Eduardo Valentin
On Fri, Mar 28, 2008 at 8:38 AM, Tony Lindgren <tony@xxxxxxxxxxx> wrote:
> * Tony Lindgren <tony@xxxxxxxxxxx> [080318 17:04]:
>
> > From: Paul Walmsley <paul@xxxxxxxxx>
> >
> > This patch adds a common clock framework for 24xx and 34xx.
> > Note that this patch does not add it to Makefile until in
> > next patch. Some functions are modified from earlier 24xx
> > clock framework code.
>
> Here's an updated version of this patch. I've folded in two more patches
> from Paul [1][2]. Patches change to use __ffs() instead of
> mask_to_shift,
> and clean up clock register defines.
>
> Regards,
>
> Tony
>
> [1] http://master.kernel.org/git/?p=linux/kernel/git/tmlind/linux-omap-2.6.git;a=commitdiff;h=f417e171cd2d2bd0302c8f420ee97295a165a39c
> [2] http://master.kernel.org/git/?p=linux/kernel/git/tmlind/linux-omap-2.6.git;a=commitdiff;h=70d19cc5c7999445b84e6ffea8e025512b877e8c
>
--
Eduardo Bezerra Valentin
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