From 3f95ad21855f750fe0428853214754f414b82daf Mon Sep 17 00:00:00 2001 From: "J. German Rivera" Date: Sat, 17 Oct 2015 15:33:14 -0500 Subject: [PATCH] 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: J. German Rivera Signed-off-by: Greg Kroah-Hartman --- 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 c4f5bdd3cb29..6eeb9fa8ae6a 100644 --- a/drivers/staging/fsl-mc/bus/mc-sys.c +++ b/drivers/staging/fsl-mc/bus/mc-sys.c @@ -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: */ - 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 7d44d8ceef9f..15e19af31115 100644 --- a/drivers/staging/fsl-mc/include/mc-sys.h +++ b/drivers/staging/fsl-mc/include/mc-sys.h @@ -40,6 +40,11 @@ #include #include +/** + * 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; -- 2.39.5