[PATCH v1] soc: rockchip: power-domain: Fix clang warning about negative shift count

From: Matthias Kaehlcke
Date: Fri Mar 10 2017 - 21:30:38 EST


The following warning is generated when building with clang:

drivers/soc/rockchip/pm_domains.c:726:22: error: shift count is negative [-Werror,-Wshift-count-negative]
[RK3399_PD_TCPD0] = DOMAIN_RK3399(8, 8, -1, false),
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/soc/rockchip/pm_domains.c:101:2: note: expanded from macro 'DOMAIN_RK3399'
DOMAIN(pwr, status, req, req, req, wakeup)
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/soc/rockchip/pm_domains.c:88:27: note: expanded from macro 'DOMAIN'
.req_mask = (req >= 0) ? BIT(req) : 0, \
^~~~~~~~
include/linux/bitops.h:6:24: note: expanded from macro 'BIT'

The BIT macro is evaluated with the negative value -1, even though the
resulting value would not be assigned. To fix this we only pass values
between 0 and 63 to BIT(). Unfortunately this means that we lose the
benefit of the compiler checking for out of bounds errors.

Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
---
drivers/soc/rockchip/pm_domains.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/soc/rockchip/pm_domains.c b/drivers/soc/rockchip/pm_domains.c
index 1c78c42416c6..6f2bb1222992 100644
--- a/drivers/soc/rockchip/pm_domains.c
+++ b/drivers/soc/rockchip/pm_domains.c
@@ -77,13 +77,15 @@ struct rockchip_pmu {

#define to_rockchip_pd(gpd) container_of(gpd, struct rockchip_pm_domain, genpd)

+#define RK_MASK(bit) ((bit >= 0) ? BIT(bit & 0x3f) : 0)
+
#define DOMAIN(pwr, status, req, idle, ack, wakeup) \
-{ \
- .pwr_mask = (pwr >= 0) ? BIT(pwr) : 0, \
- .status_mask = (status >= 0) ? BIT(status) : 0, \
- .req_mask = (req >= 0) ? BIT(req) : 0, \
- .idle_mask = (idle >= 0) ? BIT(idle) : 0, \
- .ack_mask = (ack >= 0) ? BIT(ack) : 0, \
+{ \
+ .pwr_mask = RK_MASK(pwr), \
+ .status_mask = RK_MASK(status), \
+ .req_mask = RK_MASK(req), \
+ .idle_mask = RK_MASK(idle), \
+ .ack_mask = RK_MASK(ack), \
.active_wakeup = wakeup, \
}

--
2.12.0.246.ga2ecc84866-goog