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nios2: implement fiberRtnValueSet()

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The return value of _Swap() is often treated as a "don't care" value and thus
often ignored. However, there are cases when it is desirable to have a
meaningful return value. This meaningful value can be assigned via
fiberRtnValueSet(). To that end, a new field has been added to the coop
register struct to store this value for when _Swap() needs to return that
meaningful value.

Change-Id: Ic4967fa7d602850c09ebde18e8bfd4c97cda9ec8
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2016-06-23 20:10:01 -07:00 • committed by Inaky Perez-Gonzalez
commit 8a8a2928e5
3 changed files with 15 additions and 6 deletions
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1
arch/nios2/core/offsets/offsets.c
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@ -55,6 +55,7 @@ GEN_OFFSET_SYM(t_coop, r28);
GEN_OFFSET_SYM(t_coop, ra);
GEN_OFFSET_SYM(t_coop, sp);
GEN_OFFSET_SYM(t_coop, key);
GEN_OFFSET_SYM(t_coop, retval);
/* size of the struct tcs structure sans save area for floating point regs */
GEN_ABSOLUTE_SYM(__tTCS_NOFLOAT_SIZEOF, sizeof(tTCS));

15
arch/nios2/core/swap.S
View file

@ -93,15 +93,24 @@ BRANCH_LABEL(next_chosen)
ldw ra, __tTCS_coopReg_OFFSET + __t_coop_ra_OFFSET(r11)
ldw sp, __tTCS_coopReg_OFFSET + __t_coop_sp_OFFSET(r11)
/* Restore interrupt state in status.PIE */
ldw r2, __tTCS_coopReg_OFFSET + __t_coop_key_OFFSET(r11)
andi r3, r2, NIOS2_STATUS_PIE_MSK
/* Load return value into r2 (return value register). garbage
* unless someone previously called fiberRtnValueSet(). Do this
* before we potentially unlock interrupts.
*/
ldw r2, __tTCS_coopReg_OFFSET + __t_coop_retval_OFFSET(r11)
/* irq_unlock(fiber->coopReg.key);
* key was supplied as argument to _Swap()
*/
ldw r3, __tTCS_coopReg_OFFSET + __t_coop_key_OFFSET(r11)
andi r3, r3, NIOS2_STATUS_PIE_MSK
beq r3, zero, no_unlock
rdctl r3, status
ori r3, r3, NIOS2_STATUS_PIE_MSK
wrctl status, r3
BRANCH_LABEL(no_unlock)
ret

5
arch/nios2/include/nano_private.h
View file

@ -91,6 +91,7 @@ struct s_coop {
uint32_t ra; /* Return address */
uint32_t sp; /* Stack pointer */
uint32_t key; /* IRQ status before irq_lock() and call to _Swap() */
uint32_t retval; /* Return value of _Swap() */
};
typedef struct s_coop t_coop;
@ -170,9 +171,7 @@ static ALWAYS_INLINE void nanoArchInit(void)
static ALWAYS_INLINE void fiberRtnValueSet(struct tcs *fiber,
unsigned int value)
{
ARG_UNUSED(fiber);
ARG_UNUSED(value);
/* STUB */
fiber->coopReg.retval = value;
}
static inline void _IntLibInit(void)