Messages in this thread Patch in this message | | | Date | Tue, 16 Jul 2013 18:13:24 +0100 | From | Russell King - ARM Linux <> | Subject | Re: [PATCH v3 2/7] mmc: atmel-mci: prepare clk before calling enable |
| |
On Tue, Jul 16, 2013 at 05:06:48PM +0200, Boris BREZILLON wrote: > @@ -389,9 +391,13 @@ static int atmci_regs_show(struct seq_file *s, void *v) > * consistent. > */ > spin_lock_bh(&host->lock); > - clk_enable(host->mck); > + ret = clk_prepare_enable(host->mck); > + if (ret) { > + spin_unlock_bh(&host->lock); > + goto out; > + }
NAK. This is buggy. clk_prepare() can sleep. Calling clk_prepare() even via clk_prepare_enable() is a blatent bug.
> memcpy_fromio(buf, host->regs, ATMCI_REGS_SIZE); > - clk_disable(host->mck); > + clk_disable_unprepare(host->mck); > spin_unlock_bh(&host->lock);
Now, given that the CLK API counts enables/disables, having the spin lock around the clk API calls is utterly pointless. This should be:
ret = clk_prepare_enable(host->mck); if (ret) goto out;
spin_lock_bh(&host->lock); memcpy_fromio(buf, host->regs, ATMCI_REGS_SIZE); spin_unlock_bh(&host->lock);
clk_disable_unprepare(host->mclk);
or, if you really need to have the clock enabled/disabled within the spinlock (very very very unlikely):
ret = clk_prepare(host->mck); if (ret) goto out;
spin_lock_bh(&host->lock); ret = clk_enable(host->mck); if (ret == 0) { memcpy_fromio(buf, host->regs, ATMCI_REGS_SIZE); clk_disable(host->mck); } spin_unlock_bh(&host->lock);
clk_unprepare(host->mclk); if (ret) goto out;
> @@ -1279,7 +1286,7 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) > > spin_lock_bh(&host->lock); > if (!host->mode_reg) { > - clk_enable(host->mck); > + clk_prepare_enable(host->mck);
Again, buggy - calling clk_prepare beneath a spinlock is illegal.
| |