On 12/16/2012 02:18 AM, Simon Glass wrote:
Hi,
On Fri, Nov 30, 2012 at 3:13 PM, Simon Glass sjg@chromium.org wrote:
Hi Jaehoon,
On Fri, Nov 30, 2012 at 12:25 AM, Jaehoon Chung jh80.chung@samsung.com wrote:
Hi,
This concept is very good. But I have one question. I think need to call mmc_init() one more, right? how did you save the boot time(200ms)?
On 11/29/2012 10:21 AM, Simon Glass wrote:
From: Che-Liang Chiou clchiou@chromium.org
Most of time that MMC driver spends on initializing a device is polling OCR (operation conditions register). To decouple this polling loop, device init is split into two parts: The first part fires the OCR query command, and the second part polls the result. So the caller is now no longer bound to the OCR-polling delay; he may fire the query, go somewhere and then come back later for the result.
To use this, call mmc_set_preinit() on any device which needs this.
This can save significant amounts of time on boot (e.g. 200ms) by hiding the MMC init time behind other init.
snip..
+int mmc_init(struct mmc *mmc) +{
int err = IN_PROGRESS;unsigned start = get_timer(0);if (mmc->has_init)return 0;if (!mmc->init_in_progress)err = mmc_start_init(mmc);It need not to return? if err is IN_PROGRESS, next condition is immediately run. Then i think we didn't save the time before adjust this patch.
It's a little confusing, but the way it works is that mmc_preinit() calls mmc_start_init() early in boot. Then when mmc_init() finally gets called (later) it finishes off the init. We still need mmc_init() to actually fully complete the init. If it were to return before completing the init then we would be unable to use the MMC.
if (!err || err == IN_PROGRESS)err = mmc_complete_init(mmc);debug("%s: %d, time %lu\n", __func__, err, get_timer(start)); return err;}
Does this patch look good now? I am wondering if it will be including in release, or in next?
Well, concept is very good. But i didn't see the any benefit yet. I will test more...and share the result.
Best Regards, Jaehoon Chung
Regards, Simon
[snip]
Regards, Simon