mmc/host/mmc_spi.c

124 	/* Specs say to write ones most of the time, even when the card
126 	 * This is our source of those ones.
128 	void			*ones;
234 	 * two data bits, but otherwise it's all ones.
245 		/* Card sends N(CR) (== 1..8) bytes of all-ones then one
415 	 *  - an all-ones byte to ensure the card is ready
420 	 * We init the whole buffer to all-ones, which is what we need
430 	/* Then, read up to 13 bytes (while writing all-ones):
431 	 *  - N(CR) (== 1..8) bytes of all-ones
440 	 *  - N(EC) (== 0..N) bytes of all-ones, before deselect/finish
441 	 *  - N(RC) (== 1..N) bytes of all-ones, before next command
442 	 *  - N(WR) (== 1..N) bytes of all-ones, before data write
459 	 *      + N(CX) (== 0..8) bytes of all-ones, before CSD or CID
460 	 *      + N(AC) (== 1..many) bytes of all-ones
508  * requires us to write ones; but Linux defaults to writing zeroes;
509  * so we explicitly initialize it to all ones on RX paths.
535 	 * either TX-only, or RX with TX-ones.
539 	t->tx_buf = host->ones;
550 		t->tx_buf = host->ones;
556 	 * A single block read is followed by N(EC) [0+] all-ones bytes
559 	 * Multiblock reads are followed by N(AC) [1+] all-ones bytes before
564 	 * come zero or more busy bytes, then N(WR) [1+] all-ones bytes.
565 	 * Then single block reads may deselect, and multiblock ones issue
573 		t->tx_buf = host->ones;
582  *  - caller handled preceding N(WR) [1+] all-ones bytes
587  *  - an all-ones byte ... card writes a data-response byte
588  *  - followed by N(EC) [0+] all-ones bytes, card writes zero/'busy'
672  *  - skip leading all-ones bytes ... either
680  * After single block reads, we're done; N(EC) [0+] all-ones bytes follow
697 	 * applies, before the all-ones bytes ... just cope with that.
860 		 * all-ones bytes ... skip N(BR) (0..1), scan the rest for
1149 	void			*ones;
1179 	/* We need a supply of ones to transmit.  This is the only time
1186 	ones = kmalloc(MMC_SPI_BLOCKSIZE, GFP_KERNEL);
1187 	if (!ones)
1189 	memset(ones, 0xff, MMC_SPI_BLOCKSIZE);
1218 	host->ones = ones;
1247 	host->status.tx_buf = host->ones;
1310 	kfree(ones);
1327 	kfree(host->ones);