bus: fsl-mc: use raw spin lock to serialize mc cmds

Replace the spinlock that serializes the MC commands with a raw
spinlock. This is needed for the RT kernel because there are MC
commands sent in interrupt context.
Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Link: https://lore.kernel.org/r/20200717154800.17169-3-ioana.ciornei@nxp.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/bus/fsl-mc/mc-io.c

@@ -82,7 +82,7 @@ int __must_check fsl_create_mc_io(struct device *dev,
 	mc_io->portal_phys_addr = mc_portal_phys_addr;
 	mc_io->portal_size = mc_portal_size;
 	if (flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL)
-		spin_lock_init(&mc_io->spinlock);
+		raw_spin_lock_init(&mc_io->spinlock);
 	else
 		mutex_init(&mc_io->mutex);
 

drivers/bus/fsl-mc/mc-sys.c

@@ -251,7 +251,7 @@ int mc_send_command(struct fsl_mc_io *mc_io, struct fsl_mc_command *cmd)
 		return -EINVAL;
 
 	if (mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL)
-		spin_lock_irqsave(&mc_io->spinlock, irq_flags);
+		raw_spin_lock_irqsave(&mc_io->spinlock, irq_flags);
 	else
 		mutex_lock(&mc_io->mutex);
 
@@ -287,7 +287,7 @@ int mc_send_command(struct fsl_mc_io *mc_io, struct fsl_mc_command *cmd)
 	error = 0;
 common_exit:
 	if (mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL)
-		spin_unlock_irqrestore(&mc_io->spinlock, irq_flags);
+		raw_spin_unlock_irqrestore(&mc_io->spinlock, irq_flags);
 	else
 		mutex_unlock(&mc_io->mutex);
 

include/linux/fsl/mc.h

@@ -339,7 +339,7 @@ struct fsl_mc_io {
 		 * This field is only meaningful if the
 		 * FSL_MC_IO_ATOMIC_CONTEXT_PORTAL flag is set
 		 */
-		spinlock_t spinlock;	/* serializes mc_send_command() */
+		raw_spinlock_t spinlock; /* serializes mc_send_command() */
 	};
 };