mailbox: rockchip: avoid 64-bit division

The newly added rockchip mailbox driver causes a bug in
the ARM allyesconfig build because of a division of a resource_size_t
variable that may be 64 bit wide:

drivers/mailbox/built-in.o: In function `rockchip_mbox_probe':
:(.text+0x6614): undefined reference to `__aeabi_uldivmod'

This adds a cast to size_t, which turns it into a 32-bit division
in this case. This is safe because we know that we cannot possibly
map a resource that is longer than what a pointer contains, and
in practice it will be very short instead.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

diff --git a/drivers/mailbox/rockchip-mailbox.c b/drivers/mailbox/rockchip-mailbox.c
index b79a2871227c35a1b55a1f88ec6a376fddb46952..d702a204f5c10ef5dc0d46946b9ff7495390caeb 100644 (file)
--- a/drivers/mailbox/rockchip-mailbox.c
+++ b/drivers/mailbox/rockchip-mailbox.c
@@ -213,7 +213,7 @@ static int rockchip_mbox_probe(struct platform_device *pdev)
                return PTR_ERR(mb->mbox_base);
 
        /* Each channel has two buffers for A2B and B2A */
-       mb->buf_size = resource_size(res) / (drv_data->num_chans * 2);
+       mb->buf_size = (size_t)resource_size(res) / (drv_data->num_chans * 2);
 
        mb->pclk = devm_clk_get(&pdev->dev, "pclk_mailbox");
        if (IS_ERR(mb->pclk)) {