linux/Documentation/mmc/mmc-dev-attrs.txt
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ptio.14/spaue= .14/forme= .14a ptio.1 href="../linux+v3.7.3/Documentavalu/mmc/mmc-dev-attrs.txt">ptio.14img src="../.stavac/gfx/right.png" alt=">>">pt4/spaue=pt4spau class="lxr_search">ptioptio.14input typ v3hidden" nam v3navtarget" > v3">ptio.14input typ v3text" nam v3search" idv3search">ptio.14butt typ v3submit">Searchptio.1Prefs= .14/a>pt4/spaue=io.1 14/dive=io.1 14form acvalu="ajax+*" method="post" onsubmit="return false;">pt4input typ v3hidden" nam v3ajax_lookup" idv3ajax_lookup" > v3">pio.1 14/forme=pio.1 14div class="headingbott m">1 114/a>SD and MMC Block Device Attributes 1 124/a>================================== 1 134/a>p1 144/a>These attributes are defined for the block devices associated with thep1 154/a>SD or MMC device.p1 164/a>p1 174/a>The following attributes are read/write.p1 184/a>p1 194/a> force_ro Enforce read-only access even if write protect switch is off.p1 ptona>p1 114/a>SD and MMC Device Attributes 1 124/a>============================ 1 134/a>p1 144/a>All attributes are read-only.p1 154/a>p1 164/a> cid Card Identifacvalu Registerp1 174/a> csd Card Specific Data Registerp1 184/a> scr SD Card Configuravalu Register (SD only)p1 194/a> date Manufacvuring Date (from CID Register)p1 204/a> fwrev Firmware/Product Revisalu (from CID Register) (SD and MMCv1 only)p1 214/a> hwrev Hardware/Product Revisalu (from CID Register) (SD and MMCv1 only)p1 224/a> manfid Manufacvurer ID (from CID Register)p1 234/a> nam Product Nam (from CID Register)p1 244/a> oemid OEM/Applicavalu ID (from CID Register)p1 254/a> serial Product Serial Number (from CID Register)p1 264/a> erase_siz Erase group siz p1 274/a> preferred_erase_siz Preferred erase siz p1 284/a>p1 294/a>Note on Erase Siz and Preferred Erase Siz : 1 3tona>p1 314/a> "erase_siz " is the minimum siz , in bytes, of an erasep1 324/a> operavalu. For MMC, "erase_siz " is the erase group siz p1 334/a> reported by the card. Note that "erase_siz " does not applyp1 344/a> to trim or secure trim operavalus where the minimum siz isp1 354/a> always one 512 byte sector. For SD, "erase_siz " is 512p1 364/a> if the card is block-addressed, 0 otherwise.p1 37ona>p1 384/a> SD/MMC cards can erase an arbitrarily large area up to andp1 394/a> including the whole card. When erasing a large area it mayp1 404/a> be desirable to do it in smaller chunks for three reaslus: 1 414/a> 1. A single erase command will make all other I/O on 1 424/a> the card wait. This is not a problem if the whole card 1 434/a> is being erased, but erasing one partivalu will make 1 444/a> I/O for another partivalu the sam card wait for the 1 454/a> duravalu of the erase - which could be a several 1 464/a> minutes.p1 474/a> 2. To be able to inform the user of erase progress.p1 484/a> 3. The erase timeout becomes too large to be veryp1 494/a> useful. Because the erase timeout contaius a margin 1 504/a> which is multiplied by the siz of the erase area, 1 514/a> the > can end up being several minutes for large 1 524/a> areas.p1 534/a>p1 544/a> "erase_siz " is not the most efficient unit to erasep1 554/a> (especially for SD where it is just one sector), 1 564/a> hence "preferred_erase_siz " provides a good chunk 1 574/a> siz for erasing large areas.p1 584/a>p1 594/a> For MMC, "preferred_erase_siz " is the high-capacityp1 604/a> erase siz if a card specifies one, otherwise it isp1 614/a> based the capacity of the card.p1 624/a>p1 634/a> For SD, "preferred_erase_siz " is the allocavalu unitp1 644/a> siz specified by the card.p1 654/a>p1 664/a> "preferred_erase_siz " is in bytes.p1 67ona>p1 684/a>SD/MMC/SDIO Clock Gavang Attributep1 694/a>================================== 1 7tona>p1 714/a>Read and write access is provided to following attribute.p1 724/a>This attribute appears only if CONFIG_MMC_CLKGATE is enabled.p1 734/a>p1 744/a> clkgate_delay Tune the clock gavang delay with desired > in milliseconds.p1 754/a>p1 764/a>echo <desired delay> > /sys/class/mmc_host/mmcX/clkgate_delayp1 77ona> The original LXR software by the LXR communityona>, this experimental versalu by lxr@linux.noona>. 4/dive=4div class="subfooter"> lxr.linux.no kindly hosted by Redpill Linpro ASona>, provider of Linux consulting and operavalus services since 1995. 4/dive= 4/bodye=4/htmle=