Title: [5784] trunk/drivers/mmc/host/mmc_spi.c: bug [#3713] - Use SPI lock to share bus with other SPI devices.
- Revision
- 5784
- Author
- adamliyi
- Date
- 2008-12-02 03:48:07 -0600 (Tue, 02 Dec 2008)
Log Message
bug [#3713] - Use SPI lock to share bus with other SPI devices.
Modified Paths
Diff
Modified: trunk/drivers/mmc/host/mmc_spi.c (5783 => 5784)
--- trunk/drivers/mmc/host/mmc_spi.c 2008-12-02 09:43:03 UTC (rev 5783)
+++ trunk/drivers/mmc/host/mmc_spi.c 2008-12-02 09:48:07 UTC (rev 5784)
@@ -1004,6 +1004,7 @@
#endif
/* issue command; then optionally data and stop */
+ spi_lock_bus(host->spi);
status = mmc_spi_command_send(host, mrq, mrq->cmd, mrq->data != NULL);
if (status == 0 && mrq->data) {
mmc_spi_data_do(host, mrq->cmd, mrq->data, mrq->data->blksz);
@@ -1012,7 +1013,7 @@
else
mmc_cs_off(host);
}
-
+ spi_unlock_bus(host->spi);
mmc_request_done(host->mmc, mrq);
}
@@ -1256,32 +1257,6 @@
return status;
}
- /* We can use the bus safely iff nobody else will interfere with us.
- * Most commands consist of one SPI message to issue a command, then
- * several more to collect its response, then possibly more for data
- * transfer. Clocking access to other devices during that period will
- * corrupt the command execution.
- *
- * Until we have software primitives which guarantee non-interference,
- * we'll aim for a hardware-level guarantee.
- *
- * REVISIT we can't guarantee another device won't be added later...
- */
- if (spi->master->num_chipselect > 1) {
- struct count_children cc;
-
- cc.n = 0;
- cc.bus = spi->dev.bus;
- status = device_for_each_child(spi->dev.parent, &cc,
- maybe_count_child);
- if (status < 0) {
- dev_err(&spi->dev, "can't share SPI bus\n");
- return status;
- }
-
- dev_warn(&spi->dev, "ASSUMING SPI bus stays unshared!\n");
- }
-
/* We need a supply of ones to transmit. This is the only time
* the CPU touches these, so cache coherency isn't a concern.
*
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