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firmware: arm_ffa: Add support for FFA_YIELD in direct messaging

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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.

Message-Id: <20240820-ffa_v1-2-v2-6-18c0c5f3c65e@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
This commit is contained in:
Sudeep Holla 2024-08-20 15:27:59 +01:00
parent aaef3bc981
commit eaca7ef8f3
1 changed files with 15 additions and 8 deletions
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23
drivers/firmware/arm_ffa/driver.c
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@ -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);