tree 835d2d6ac10fa3efb9a52a1af47ba96a33959332
parent 37a50b97d100f3f15ff63dc999f1b807447b8eef
author Andrew Gabbasov <andrew_gabbasov@mentor.com> 1419524544 -0600
committer Pantelis Antoniou <pantelis.antoniou@konsulko.com> 1421682112 +0200

mmc: Avoid redundant switching to 1-bit bus width for MMC cards

If all the commands switching an MMC card to 4- or 8-bit bus width fail,
and the bus width for the controller and the driver is still set
to default 1 bit, there is no need to send one more command to switch
the card to 1-bit bus width. Also, if the card or host controller do not
support wider bus widths, there is no need to send a switch command at all.

However, if one of switch commands succeeds, but the subsequent ext_csd
fields comparison fails, the card should be switched to some other bus width
(next in the list for the loop), or to default 1-bit bus width as a last
resort. That's why it would be incorrect to just remove the 1-bit bus width
case from the list, it should still be processed in some cases.

panto: Minor cosmetic edit removing superfluous parentheses.

Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
Tested-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>