Hi Chuanxiao, > -----Original Message----- > From: Dong, Chuanxiao [mailto:chuanxiao.dong@xxxxxxxxx] > Sent: Monday, February 16, 2015 11:04 AM > To: Alex Lemberg > Cc: linux-mmc@xxxxxxxxxxxxxxx; Yuliy Izrailov > Subject: RE: [RFC PATCH 0/5]mmc: Soft Command queue implementation for > eMMC5.1 device > > > > -----Original Message----- > > From: Alex Lemberg [mailto:Alex.Lemberg@xxxxxxxxxxx] > > Sent: Monday, February 16, 2015 4:55 PM > > To: Dong, Chuanxiao > > Cc: linux-mmc@xxxxxxxxxxxxxxx; Yuliy Izrailov > > Subject: RE: [RFC PATCH 0/5]mmc: Soft Command queue implementation for > > eMMC5.1 device > > > > Hi Chuanxiao, > > > > > -----Original Message----- > > > From: Dong, Chuanxiao [mailto:chuanxiao.dong@xxxxxxxxx] > > > Sent: Friday, February 13, 2015 2:33 AM > > > To: Alex Lemberg > > > Cc: linux-mmc@xxxxxxxxxxxxxxx; Yuliy Izrailov > > > Subject: RE: [RFC PATCH 0/5]mmc: Soft Command queue implementation > > > for > > > eMMC5.1 device > > > > > > Hi Alex, > > > > > > Can you please point me to the 5.1 spec which has the description of > > > "" ready for execution" for each task should be cleared by the > > > device only when the last data block has been fully transferred over > > > the eMMC bus."? From my side, I have a draft version which I didn't > > > find the similar > > description. > > > > We also use a draft version of the spec. > > Since March 2014, all drafts contain that "ready for execution" > > description, including the last draft that was approved. > > For CMD46: "When the last data block has been fully transferred over > > the e*MMC bus, the device should clear "ready for execution" for the task." > > For CMD47: "When the busy signal following the last data block is > > released, the device should clear "ready for execution" for the task." > > I see. My draft doesn't have these two sentences in the CMD46/47 session. I > will follow up with latest version to update my source code. Thank you! > > BTW, why eMMC device cannot clear the "ready for execution" until > CMD46/47 completed totally? Any restriction of this implementation? This is how the spec is defining this feature. I believe it was done to prevent host from sending new command with same TaskID while that TaskID executed. > > Thanks > Chuanxiao > > > > > > > > > The current logical in driver is after receiving the command > > > complete interrupt of CMD46/47, driver will send another CMD13 to > > > check the ready for execution task without waiting for any data > > > transfer complete interrupt. If it is as you mentioned, the ready > > > for execution bit won't be cleared until the data transfer complete > > > interrupt is received, > > right? > > > > Right. > > > > > > > > So far with the Samsung eMMC which is the only one I have, I didn't > > > see issue with this logical. > > > > > > Thanks > > > Chuanxiao > > > > > > > -----Original Message----- > > > > From: Alex Lemberg [mailto:Alex.Lemberg@xxxxxxxxxxx] > > > > Sent: Wednesday, February 11, 2015 10:01 PM > > > > To: Dong, Chuanxiao > > > > Cc: linux-mmc@xxxxxxxxxxxxxxx; Yuliy Izrailov > > > > Subject: RE: [RFC PATCH 0/5]mmc: Soft Command queue implementation > > > > for > > > > eMMC5.1 device > > > > > > > > Hi Chuanxiao, > > > > > > > > I have a question from the review of your SW CMDQ driver code. > > > > > > > > From the eMMC5.1 spec, the "ready for execution" for each task > > > > should be cleared by the device only when the last data block has > > > > been fully transferred over the eMMC bus. > > > > > > > > However, from the code, I can recognize the following suspected case: > > > > > > > > 1. Host sends CMD44/45 commands for TID#0 2. Host sends CMD13 > > > > (QSR) > > > > -> returned TID#0 ready for execution 3. Host sends CMD46 for TID#0 4. > > > > During the data transfer, host may send CMD13 (QSR) -> returned > > > > TID#0 ready for execution (which is true since data is still in transfer) 5. > > > > Host sends CMD46 for > > > > TID#0 (same as sent in bullet#3) - which is a problem. > > > > > > > > Please advise if my assumption above is correct. > > > > > > > > Thanks, > > > > Alex > > > > > > > > > > > > > -----Original Message----- > > > > > From: linux-mmc-owner@xxxxxxxxxxxxxxx [mailto:linux-mmc- > > > > > owner@xxxxxxxxxxxxxxx] On Behalf Of Chuanxiao Dong > > > > > Sent: Friday, December 19, 2014 10:05 AM > > > > > To: linux-mmc@xxxxxxxxxxxxxxx > > > > > Subject: [RFC PATCH 0/5]mmc: Soft Command queue implementation > > > > > for > > > > > eMMC5.1 device > > > > > > > > > > Hello, > > > > > > > > > > Seems community already have some implementation for the eMMC5.1 > > > > > device command queue feature, but that require the eMMC host > > > > > controller to support CMDQ. In my platform, I don't have this > > > > > kind of eMMC host controller but I have a Samsung eMMC5.1 device > > > > > which can > > > > support the Command queue. > > > > > > > > > > With this limitation, I have to let eMMC host controller to > > > > > manually send the CMD44/45/13/46/47. So in this way, more > > > > > commands are needed for an I/O request, more interrupts/schedule > > > > > are needed in > > driver. > > > > > > > > > > Even this way have some more software overhead, but it can still > > > > > use the > > > > > eMMC5.1 device Command queue feature. After test with the iozone > > > > > command: > > > > > "iozone -zec -t 4 -i0 -i2 -F iozonefile1 iozonefile2 iozonefile3 > > > > > iozonefile4 -+n -I -r 4k -s 500m -O -R -+r -+D" to test random > > > > > performance, I saw a performance improvment for random read on > > > > > my > > > > eMMC5.1 device: > > > > > > > > > > Random read > > > > > SW CMDQ: 5544.6 > > > > > Normal Read: 3993.05 > > > > > > > > > > So I want to send this serial patches as RFC patch for reviewing > > > > > > > > > > > > > > > Chuanxiao Dong (5): > > > > > mmc: replace sbc to precmd and add postcmd > > > > > mmc: host: add runtime PM for host class dev > > > > > mmc: queue: change mqrq_cur and mqrq_pre to mq qdepth > > > > > mmc: core: add support for CMDQ feature in MMC Core stack > > > > > mmc: sdhci: add SW CMDQ support for CHT SDHCI host > > > > > > > > > > drivers/mmc/card/block.c | 538 > > > > > ++++++++++++++++++++++++++++++++++++++--- > > > > > drivers/mmc/card/queue.c | 213 ++++++++-------- > > > > > drivers/mmc/card/queue.h | 14 +- > > > > > drivers/mmc/core/core.c | 78 +++++- > > > > > drivers/mmc/core/host.c | 14 ++ > > > > > drivers/mmc/core/mmc.c | 43 +++- > > > > > drivers/mmc/host/dw_mmc.c | 8 +- > > > > > drivers/mmc/host/mmci.c | 14 +- > > > > > drivers/mmc/host/omap_hsmmc.c | 18 +- > > > > > drivers/mmc/host/sdhci-acpi.c | 1 - > > > > > drivers/mmc/host/sdhci-pci.c | 1 - > > > > > drivers/mmc/host/sdhci.c | 137 +++++++++-- > > > > > include/linux/mmc/card.h | 3 + > > > > > include/linux/mmc/core.h | 5 +- > > > > > include/linux/mmc/host.h | 5 + > > > > > include/linux/mmc/mmc.h | 21 ++ > > > > > include/linux/mmc/pm.h | 1 + > > > > > include/linux/mmc/sdhci.h | 1 + > > > > > 18 files changed, 909 insertions(+), 206 deletions(-) > > > > > > > > > > -- > > > > > 1.7.10.4 > > > > > -- > > > > > To unsubscribe from this list: send the line "unsubscribe linux-mmc" > > > > > in the body of a message to majordomo@xxxxxxxxxxxxxxx More > > > > > majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
