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: J. German Rivera <German.Rivera@xxxxxxxxxxxxx>
---
drivers/staging/fsl-mc/bus/mc-sys.c | 53 +++++++++++++++++++++++++++++++--
drivers/staging/fsl-mc/include/mc-sys.h | 5 ++++
2 files changed, 55 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/fsl-mc/bus/mc-sys.c b/drivers/staging/fsl-mc/bus/mc-sys.c
index c4f5bdd..6eeb9fa 100644
--- a/drivers/staging/fsl-mc/bus/mc-sys.c
+++ b/drivers/staging/fsl-mc/bus/mc-sys.c
@@ -339,20 +339,63 @@ static int mc_polling_wait_preemptible(struct fsl_mc_io *mc_io,
}
/**
+ * 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
*
* @mc_io: MC I/O object to be used
* @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:
*/
- error = mc_polling_wait_preemptible(mc_io, cmd, &status);
+ 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;
diff --git a/drivers/staging/fsl-mc/include/mc-sys.h b/drivers/staging/fsl-mc/include/mc-sys.h
index 7d44d8c..15e19af 100644
--- a/drivers/staging/fsl-mc/include/mc-sys.h
+++ b/drivers/staging/fsl-mc/include/mc-sys.h
@@ -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;
--
2.3.3
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