mmc: atmel-mci: fix bad variable type for clkdiv

clkdiv is declared as an u32 but it can be set to a negative value
causing a huge divisor value. Change its type to int to avoid this case.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: <stable@vger.kernel.org> # 3.4 and later
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 03d7c7521d97..9a39e0b7e583 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -1304,7 +1304,7 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 
         if (ios->clock) {
                 unsigned int clock_min = ~0U;
-                u32 clkdiv;
+                int clkdiv;
 
                 spin_lock_bh(&host->lock);
                 if (!host->mode_reg) {
@@ -1328,7 +1328,12 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
                 /* Calculate clock divider */
                 if (host->caps.has_odd_clk_div) {
                         clkdiv = DIV_ROUND_UP(host->bus_hz, clock_min) - 2;
-                        if (clkdiv > 511) {
+                        if (clkdiv < 0) {
+                                dev_warn(&mmc->class_dev,
+                                         "clock %u too fast; using %lu\n",
+                                         clock_min, host->bus_hz / 2);
+                                clkdiv = 0;
+                        } else if (clkdiv > 511) {
                                 dev_warn(&mmc->class_dev,
                                          "clock %u too slow; using %lu\n",
                                          clock_min, host->bus_hz / (511 + 2));