4.15-stable review patch. If anyone has any objections, please let me know.
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From: Logan Gunthorpe logang@deltatee.com
[ Upstream commit 4e5ca2d930aa8714400aedf4bf1dc959cb04280f ]
Add a check to ensure iowrite64 is only used if it is atomic.
It was decided in [1] that the tilcdc driver should not be using an atomic operation (so it was left out of this patchset). However, it turns out that through the drm code, a nonatomic header is actually included:
include/linux/io-64-nonatomic-lo-hi.h is included from include/drm/drm_os_linux.h:9:0, from include/drm/drmP.h:74, from include/drm/drm_modeset_helper.h:26, from include/drm/drm_atomic_helper.h:33, from drivers/gpu/drm/tilcdc/tilcdc_crtc.c:19:
And thus, without this change, this patchset would inadvertantly change the behaviour of the tilcdc driver.
[1] lkml.kernel.org/r/CAK8P3a2HhO_zCnsTzq7hmWSz5La5Thu19FWZpun16iMnyyNreQ@mail.gmail.com
Signed-off-by: Logan Gunthorpe logang@deltatee.com Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com Cc: Jyri Sarha jsarha@ti.com Cc: Arnd Bergmann arnd@arndb.de Cc: Tomi Valkeinen tomi.valkeinen@ti.com Cc: David Airlie airlied@linux.ie Signed-off-by: Jyri Sarha jsarha@ti.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/tilcdc/tilcdc_regs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/gpu/drm/tilcdc/tilcdc_regs.h +++ b/drivers/gpu/drm/tilcdc/tilcdc_regs.h @@ -133,7 +133,7 @@ static inline void tilcdc_write64(struct struct tilcdc_drm_private *priv = dev->dev_private; volatile void __iomem *addr = priv->mmio + reg;
-#ifdef iowrite64 +#if defined(iowrite64) && !defined(iowrite64_is_nonatomic) iowrite64(data, addr); #else __iowmb();