On Fri, Sep 6, 2019 at 2:57 PM Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > > On Fri, 6 Sep 2019 at 14:26, Belisko Marek <marek.belisko@xxxxxxxxx> wrote: > > > > On Fri, Sep 6, 2019 at 2:19 PM Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > > > > > > On Fri, 6 Sep 2019 at 11:14, Belisko Marek <marek.belisko@xxxxxxxxx> wrote: > > > > > > > > Hi, > > > > > > > > I'm trying to get some insights about how to debug emmc speed issue. > > > > We're using board with am437x CPU using mainline 4.12 kernel (added > > > > only devicetree for our custom board). eMMC is 8bit connect (using > > > > sandisk SDINBDG4-8G-I1 chip). > > > > > > > > Issue is that when copying data from SD card to eMMC we get throughput > > > > only ~300kB/s (it should be bit higher IIRC). I'm just looking for > > > > some advice what to check and how to find out where issue can be > > > > (still unsure if SW or HW). Thanks a lot. > > > > > > Mount debugfs and look at the ios node for the mmc host in question. > > > There is information about clocks, busdwidth, etc. > > Thanks for info. From below it looks quite ok: > > clock: 52000000 Hz > > vdd: 21 (3.3 ~ 3.4 V) > > bus mode: 2 (push-pull) > > chip select: 0 (don't care) > > power mode: 2 (on) > > bus width: 3 (8 bits) > > timing spec: 1 (mmc high-speed) > > signal voltage: 0 (3.30 V) > > driver type: 0 (driver type B) > > > > compared to gumstix poblano (same cpu): > > cat /sys/kernel/debug/mmc1/ios > > clock: 50000000 Hz > > vdd: 21 (3.3 ~ 3.4 V) > > bus mode: 2 (push-pull) > > chip select: 0 (don't care) > > power mode: 2 (on) > > bus width: 2 (4 bits) > > timing spec: 2 (sd high-speed) > > signal voltage: 0 (3.30 V) > > driver type: 0 (driver type B) > > > > difference is in bus width (I'm confused as poblano according dts + > > schematics should also have 8 bit interface) and timing spec are > > different for my case. Anything else I can check? Thanks. > > This looks fine to me. I think you need to do some deeper debug to > find out what the issue is, sorry for not being able to help any more > than this. Isn't timing spec doing any difference in speed? Just curious. > > Of course you already tried reading/writing to the eMMC and SD > independently, so you have a reference of the throughput values? For poblano I have with bs=4096 throughput ~ 10MB/sec while on my platform only 1,6MB/s when copying same file to eMMC. So trying to understand what can be an issue. AFAIK on my platform I have some new Sandisk eMMC (5.2). Could be possible that support for that needs to be added or interface to eMMC is still the same? Thanks. > > Kind regards > Uffe BR, marek
