[PATCH 13/20] mci: allocate sector_buf on demand

[Ahmad Fatoum]

The MCI core uses a common bounce buffer for unaligned block
reads/writes as well as sd_change_freq. This buffer is allocated at
device initcall level, same as the MMC drivers themselves.

For CONFIG_MCI_STARTUP=y configurations this seems to imply that
sd_change_freq could attempt writing the NULL page. Avoid this
by just allocating the buffer when the first MMC device is registered.

This doesn't solve all issues; so add a comment noting that.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 drivers/mci/mci-core.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/mci/mci-core.c b/drivers/mci/mci-core.c
index 70a8b971ca6d..196fecdbd090 100644
--- a/drivers/mci/mci-core.c
+++ b/drivers/mci/mci-core.c
@@ -1789,6 +1789,11 @@ static int mci_card_probe(struct mci *mci)
 		mci->cdevname = basprintf("disk%d", disknum);
 	}
 
+	if (!sector_buf)
+		sector_buf = dma_alloc(SECTOR_SIZE);
+
+	/* FIXME we don't check sector_buf against the device dma mask here */
+
 	rc = mci_startup(mci);
 	if (rc) {
 		dev_warn(&mci->dev, "Card's startup fails with %d\n", rc);
@@ -1850,15 +1855,6 @@ static int mci_set_probe(struct param_d *param, void *priv)
 	return 0;
 }
 
-static int mci_init(void)
-{
-	sector_buf = dma_alloc(SECTOR_SIZE);
-
-	return 0;
-}
-
-device_initcall(mci_init);
-
 int mci_detect_card(struct mci_host *host)
 {
 	int rc;
-- 
2.29.2