From: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
The HSMCI operates at a rate of up to Master Clock divided by two.
Moreover previous calculation can cause overflows and so wrong
timeouts.
Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
---
drivers/mmc/host/atmel-mci.c | 9 ++++++++-
1 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index e4449a5..3a57964 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -480,7 +480,14 @@ err:
static inline unsigned int atmci_ns_to_clocks(struct atmel_mci *host,
unsigned int ns)
{
- return (ns * (host->bus_hz / 1000000) + 999) / 1000;
+ /*
+ * It is easier here to use us instead of ns for the timeout,
+ * it prevents from overflows during calculation.
+ */
+ unsigned int us = DIV_ROUND_UP(ns, 1000);
+
+ /* Maximum clock frequency is host->bus_hz/2 */
+ return us * (DIV_ROUND_UP(host->bus_hz, 2000000));
}
static void atmci_set_timeout(struct atmel_mci *host,
--
1.7.5.4
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