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: J. German Rivera <German.Rivera@xxxxxxxxxxxxx>
---
Changes in v2:
- Added missing Signed-off-by entry
drivers/staging/fsl-mc/bus/mc-sys.c | 25 ++++++++++++++++++++++---
drivers/staging/fsl-mc/include/mc-sys.h | 29 +++++++++++++++++++++++++++++
2 files changed, 51 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/fsl-mc/bus/mc-sys.c b/drivers/staging/fsl-mc/bus/mc-sys.c
index 6eeb9fa..6e14892 100644
--- a/drivers/staging/fsl-mc/bus/mc-sys.c
+++ b/drivers/staging/fsl-mc/bus/mc-sys.c
@@ -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);
diff --git a/drivers/staging/fsl-mc/include/mc-sys.h b/drivers/staging/fsl-mc/include/mc-sys.h
index 15e19af..c5038cc 100644
--- a/drivers/staging/fsl-mc/include/mc-sys.h
+++ b/drivers/staging/fsl-mc/include/mc-sys.h
@@ -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,
--
2.3.3
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