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Commit 63f2be5c authored by J. German Rivera's avatar J. German Rivera Committed by Greg Kroah-Hartman
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staging: fsl-mc: Added serialization to mc_send_command() 



When the same portal is used to call mc_send_command() from two
different threads or a thread and an interrupt handler, serialization
is required, as the MC only supports one outstanding command per MC
portal. Thus, a new command should not be sent to the MC until the
last command sent has been responded by the MC.

Signed-off-by: default avatarJ. German Rivera <German.Rivera@freescale.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3f95ad21

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

+22 −3
Original line number Diff line number Diff line
@@ -88,6 +88,11 @@ int __must_check fsl_create_mc_io(struct device *dev, 
	mc_io->flags = flags;

	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);

	else

		mutex_init(&mc_io->mutex);



	res = devm_request_mem_region(dev,

				      mc_portal_phys_addr,

				      mc_portal_size,
@@ -391,11 +396,17 @@ int mc_send_command(struct fsl_mc_io *mc_io, struct mc_command *cmd) 
{

	int error;

	enum mc_cmd_status status;

	unsigned long irq_flags = 0;



	if (WARN_ON(in_irq() &&

		    !(mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL)))

		return -EINVAL;



	if (mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL)

		spin_lock_irqsave(&mc_io->spinlock, irq_flags);

	else

		mutex_lock(&mc_io->mutex);



	/*

	 * Send command to the MC hardware:

	 */
@@ -410,7 +421,7 @@ int mc_send_command(struct fsl_mc_io *mc_io, struct mc_command *cmd) 
		error = mc_polling_wait_atomic(mc_io, cmd, &status);



	if (error < 0)

		return error;

		goto common_exit;



	if (status != MC_CMD_STATUS_OK) {

		pr_debug("MC command failed: portal: %#llx, obj handle: %#x, command: %#x, status: %s (%#x)\n",
@@ -420,9 +431,17 @@ int mc_send_command(struct fsl_mc_io *mc_io, struct mc_command *cmd) 
			 mc_status_to_string(status),

			 (unsigned int)status);



		return mc_status_to_error(status);

		error = mc_status_to_error(status);

		goto common_exit;

	}



	return 0;

	error = 0;

common_exit:

	if (mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL)

		spin_unlock_irqrestore(&mc_io->spinlock, irq_flags);

	else

		mutex_unlock(&mc_io->mutex);



	return error;

}

EXPORT_SYMBOL(mc_send_command);

drivers/staging/fsl-mc/include/mc-sys.h

+29 −0
Original line number Diff line number Diff line
@@ -39,6 +39,8 @@ 
#include <linux/errno.h>

#include <linux/io.h>

#include <linux/dma-mapping.h>

#include <linux/mutex.h>

#include <linux/spinlock.h>



/**

 * Bit masks for a MC I/O object (struct fsl_mc_io) flags
@@ -56,6 +58,20 @@ struct mc_command; 
 * @portal_phys_addr: MC command portal physical address

 * @portal_virt_addr: MC command portal virtual address

 * @dpmcp_dev: pointer to the DPMCP device associated with the MC portal.

 *

 * Fields are only meaningful if the FSL_MC_IO_ATOMIC_CONTEXT_PORTAL flag is not

 * set:

 * @mutex: Mutex to serialize mc_send_command() calls that use the same MC

 * portal, if the fsl_mc_io object was created with the

 * FSL_MC_IO_ATOMIC_CONTEXT_PORTAL flag off. mc_send_command() calls for this

 * fsl_mc_io object must be made only from non-atomic context.

 *

 * Fields are only meaningful if the FSL_MC_IO_ATOMIC_CONTEXT_PORTAL flag is

 * set:

 * @spinlock: Spinlock to serialize mc_send_command() calls that use the same MC

 * portal, if the fsl_mc_io object was created with the

 * FSL_MC_IO_ATOMIC_CONTEXT_PORTAL flag on. mc_send_command() calls for this

 * fsl_mc_io object can be made from atomic or non-atomic context.

 */

struct fsl_mc_io {

	struct device *dev;
@@ -64,6 +80,19 @@ struct fsl_mc_io { 
	phys_addr_t portal_phys_addr;

	void __iomem *portal_virt_addr;

	struct fsl_mc_device *dpmcp_dev;

	union {

		/*

		 * This field is only meaningful if the

		 * FSL_MC_IO_ATOMIC_CONTEXT_PORTAL flag is not set

		 */

		struct mutex mutex; /* serializes mc_send_command() */



		/*

		 * This field is only meaningful if the

		 * FSL_MC_IO_ATOMIC_CONTEXT_PORTAL flag is set

		 */

		spinlock_t spinlock;	/* serializes mc_send_command() */

	};

};



int __must_check fsl_create_mc_io(struct device *dev,