Successful completion of both direct messaging function can be indicated through an invocation of FFA_YIELD or GGA_INTERRUPT by the callee.
FFA_INTERRUPT indicates that the direct request was interrupted and must be resumed through the FFA_RUN interface which is already done in the driver.
FFA_YIELD indicates that the receiver endpoint has transitioned to the blocked runtime state and must be resumed through the FFA_RUN interface. However, the way receiver endpoint gets unblocked is implementation defined. So, the driver just sleeps for 1 - 2ms and issues FFA_RUN. It can return to the caller with FFA_YIELD is the receiver endpoint is still blocked.
Signed-off-by: Sudeep Holla sudeep.holla@arm.com --- drivers/firmware/arm_ffa/driver.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c index 8af41be4b1c1..90102ed7bd18 100644 --- a/drivers/firmware/arm_ffa/driver.c +++ b/drivers/firmware/arm_ffa/driver.c @@ -26,6 +26,7 @@ #include <linux/arm_ffa.h> #include <linux/bitfield.h> #include <linux/cpuhotplug.h> +#include <linux/delay.h> #include <linux/device.h> #include <linux/hashtable.h> #include <linux/interrupt.h> @@ -397,6 +398,18 @@ static int ffa_id_get(u16 *vm_id) return 0; }
+static inline void ffa_msg_send_wait_for_completion(ffa_value_t *ret) +{ + while (ret->a0 == FFA_INTERRUPT || ret->a0 == FFA_YIELD) { + if (ret->a0 == FFA_YIELD) + fsleep(1000); + + invoke_ffa_fn((ffa_value_t){ + .a0 = FFA_RUN, .a1 = ret->a1, + }, ret); + } +} + static int ffa_msg_send_direct_req(u16 src_id, u16 dst_id, bool mode_32bit, struct ffa_send_direct_data *data) { @@ -417,10 +430,7 @@ static int ffa_msg_send_direct_req(u16 src_id, u16 dst_id, bool mode_32bit, .a6 = data->data3, .a7 = data->data4, }, &ret);
- while (ret.a0 == FFA_INTERRUPT) - invoke_ffa_fn((ffa_value_t){ - .a0 = FFA_RUN, .a1 = ret.a1, - }, &ret); + ffa_msg_send_wait_for_completion(&ret);
if (ret.a0 == FFA_ERROR) return ffa_to_linux_errno((int)ret.a2); @@ -482,10 +492,7 @@ static int ffa_msg_send_direct_req2(u16 src_id, u16 dst_id, const uuid_t *uuid,
invoke_ffa_fn(args, &ret);
- while (ret.a0 == FFA_INTERRUPT) - invoke_ffa_fn((ffa_value_t){ - .a0 = FFA_RUN, .a1 = ret.a1, - }, &ret); + ffa_msg_send_wait_for_completion(&ret);
if (ret.a0 == FFA_ERROR) return ffa_to_linux_errno((int)ret.a2);