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Commit 3f95ad21 authored by J. German Rivera's avatar J. German Rivera Committed by Greg Kroah-Hartman
Browse files

staging: fsl-mc:Added support for atomic portals 



Refactored mc_send_command() to support two flavors of polling:
- preemptible (for non-atomic portals), which was already supported.
  It calls usleep_range() between polling iterations.
- non-preemptible (for atomic portals), which is needed when
  mc_send_command() is called with interrupts disabled.
  It calls udelay() between polling iterations.

Signed-off-by: default avatarJ. German Rivera <German.Rivera@freescale.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 140305e7

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

+50 −3
Original line number Diff line number Diff line
@@ -338,6 +338,47 @@ static int mc_polling_wait_preemptible(struct fsl_mc_io *mc_io, 
	return 0;

}



/**

 * Waits for the completion of an MC command doing atomic polling.

 * udelay() is called between polling iterations.

 *

 * @mc_io: MC I/O object to be used

 * @cmd: command buffer to receive MC response

 * @mc_status: MC command completion status

 */

static int mc_polling_wait_atomic(struct fsl_mc_io *mc_io,

				  struct mc_command *cmd,

				  enum mc_cmd_status *mc_status)

{

	enum mc_cmd_status status;

	unsigned long timeout_usecs = MC_CMD_COMPLETION_TIMEOUT_MS * 1000;



	BUILD_BUG_ON((MC_CMD_COMPLETION_TIMEOUT_MS * 1000) %

		     MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS != 0);



	for (;;) {

		status = mc_read_response(mc_io->portal_virt_addr, cmd);

		if (status != MC_CMD_STATUS_READY)

			break;



		udelay(MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS);

		timeout_usecs -= MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS;

		if (timeout_usecs == 0) {

			pr_debug("MC command timed out (portal: %#llx, obj handle: %#x, command: %#x)\n",

				 mc_io->portal_phys_addr,

				 (unsigned int)

					MC_CMD_HDR_READ_TOKEN(cmd->header),

				 (unsigned int)

					MC_CMD_HDR_READ_CMDID(cmd->header));



			return -ETIMEDOUT;

		}

	}



	*mc_status = status;

	return 0;

}



/**

 * Sends a command to the MC device using the given MC I/O object

 *
@@ -345,14 +386,16 @@ static int mc_polling_wait_preemptible(struct fsl_mc_io *mc_io, 
 * @cmd: command to be sent

 *

 * Returns '0' on Success; Error code otherwise.

 *

 * NOTE: This function cannot be invoked from from atomic contexts.

 */

int mc_send_command(struct fsl_mc_io *mc_io, struct mc_command *cmd)

{

	int error;

	enum mc_cmd_status status;



	if (WARN_ON(in_irq() &&

		    !(mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL)))

		return -EINVAL;



	/*

	 * Send command to the MC hardware:

	 */
@@ -361,7 +404,11 @@ int mc_send_command(struct fsl_mc_io *mc_io, struct mc_command *cmd) 
	/*

	 * Wait for response from the MC hardware:

	 */

	if (!(mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL))

		error = mc_polling_wait_preemptible(mc_io, cmd, &status);

	else

		error = mc_polling_wait_atomic(mc_io, cmd, &status);



	if (error < 0)

		return error;

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

+5 −0
Original line number Diff line number Diff line
@@ -40,6 +40,11 @@ 
#include <linux/io.h>

#include <linux/dma-mapping.h>



/**

 * Bit masks for a MC I/O object (struct fsl_mc_io) flags

 */

#define FSL_MC_IO_ATOMIC_CONTEXT_PORTAL	0x0001



struct fsl_mc_resource;

struct mc_command;