mmc: Driver for CB710/720 memory card reader (MMC part)

Hello Michał Mirosław,

The patch 5f5bac8272be: "mmc: Driver for CB710/720 memory card reader (MMC part)" from May 22, 2009, leads to the following static checker warning:

	drivers/mmc/host/cb710-mmc.c:579 cb710_mmc_set_ios()
	warn: 'err' can be either negative or positive

drivers/mmc/host/cb710-mmc.c
112
113 static int cb710_check_event(struct cb710_slot *slot, u8 what) 114 {
115 u16 status;
116
117 status = cb710_read_port_16(slot, CB710_MMC_STATUS_PORT);
118
119 if (status & CB710_MMC_S0_FIFO_UNDERFLOW) {
120 /* it is just a guess, so log it */
121 dev_dbg(cb710_slot_dev(slot),
122 "CHECK : ignoring bit 6 in status %04X\n", status);
123 cb710_write_port_8(slot, CB710_MMC_STATUS0_PORT,
124 CB710_MMC_S0_FIFO_UNDERFLOW);
125 status &= ~CB710_MMC_S0_FIFO_UNDERFLOW;
126 }
127
128 if (status & CB710_MMC_STATUS_ERROR_EVENTS) {
129 dev_dbg(cb710_slot_dev(slot),
130 "CHECK : returning EIO on status %04X\n", status);
131 cb710_write_port_8(slot, CB710_MMC_STATUS0_PORT, status & 0xFF);
132 cb710_write_port_8(slot, CB710_MMC_STATUS1_PORT,
133 CB710_MMC_S1_RESET);
134 return -EIO;
135 }
136
137 /* 'what' is a bit in MMC_STATUS1 */
138 if ((status >> 8) & what) {
139 cb710_write_port_8(slot, CB710_MMC_STATUS1_PORT, what);
140 return 1;

There are two callers to this function. It appears to me that one expects zero on error and one expects non-zero on error. It is confusing and there are no comments explaining the return codes.

141 }
142
143 return 0;
144 }

regards,
dan carpenter

Hah. The code is correct, though I admit that it's not obvious at first glance. Feel free to send a patch. :-)

Call inside cb710_wait_for_event() is spinning while there's no error and the requested event was not signalled. The call from cb710_mmc_powerup() is there only to check for error condition and since it gets 0 in 'what' it will never return 1 (>0).

Best Regards,
Michał Mirosław