Re: 1024bytes/sect microSD support

[Paul Fleischer <paul%xpg.dk@localhost>]

2009/11/27 KIYOHARA Takashi <kiyohara%kk.iij4u.or.jp@localhost>:
[snip]
>> : I think that it is necessary to always adjust us to 512 bytes.  If this
>> : is not supported, we cannot have Linux and interchangeability.
>> : However, I do not know how to set more better it.  Does anyone have an
>> : idea?

As far as I can read from the SD Simplified Physical Layer
Specification[1] page 19, the 2Gb cards are bit of an exception as
their CSD announces a block size of 1024, but the actual block size to
use is 512kb.

I have patched dev/sdmmc/sdmmc_mem.c to follow this exception. I bet
the patch can be made more pretty, but it seems to work.

Cheers,
Paul

[1]: http://www.sdcard.org/developers/tech/sdcard/pls/

Index: dev/sdmmc/sdmmc_mem.c
===================================================================
RCS file: /cvsroot/src/sys/dev/sdmmc/sdmmc_mem.c,v
retrieving revision 1.2.2.2
diff -u -r1.2.2.2 sdmmc_mem.c
--- dev/sdmmc/sdmmc_mem.c       7 Oct 2009 15:41:13 -0000       1.2.2.2
+++ dev/sdmmc/sdmmc_mem.c       24 Nov 2009 22:23:19 -0000
@@ -290,6 +290,8 @@
        };
        struct sdmmc_csd *csd = &sf->csd;
        int e, m;
+       int is_2gb_v1_card = 0;
+

        if (ISSET(sc->sc_flags, SMF_SD_MODE)) {
                /*
@@ -309,6 +311,14 @@
                        DPRINTF(("%s: SD Ver.1.0\n", SDMMCDEVNAME(sc)));
                        csd->capacity = SD_CSD_CAPACITY(resp);
                        csd->read_bl_len = SD_CSD_READ_BL_LEN(resp);
+                       
+                       /* Special handling for 2GB SD1.0 cards, not quite sure 
if this
+                          is the right way to detect it, though.
+                        */
+                       if ( (1<<csd->read_bl_len)*csd->capacity >= 
1961*1024*1024 ) {
+                               is_2gb_v1_card = 1;
+                       }
+
                        break;

                default:
@@ -347,6 +357,13 @@
            sdmmc_chip_host_maxblklen(sc->sc_sct, sc->sc_sch));
        if (csd->sector_size < (1 << csd->read_bl_len))
                csd->capacity *= (1 << csd->read_bl_len) / csd->sector_size;
+
+       /* Handle the special case of 2GB ver1.0 SD cards */
+       if (is_2gb_v1_card && csd->sector_size > 512) {
+               csd->capacity *= csd->sector_size / 512;
+               csd->sector_size = 512;
+       }
+
        csd->sector_size_sb = ffs(csd->sector_size) - 1;

        if (sc->sc_busclk > csd->tran_speed)