| /* |
| (C) Copyright IBM Corp. 2008 |
| |
| All rights reserved. |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions are met: |
| |
| * Redistributions of source code must retain the above copyright notice, |
| this list of conditions and the following disclaimer. |
| * Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
| documentation and/or other materials provided with the distribution. |
| * Neither the name of IBM nor the names of its contributors may be |
| used to endorse or promote products derived from this software without |
| specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /* Second Level Interrupt handler and related services for SPU timers. */ |
| #include "spu_timer_internal.h" |
| /* Resets decrementer to the specified value. Also updates software timebase |
| to account for the time between the last decrementer reset and now. There |
| are two cases: |
| * Called by application to start a new timer. |
| * Called by spu_clock to active the next timer. |
| In both cases, the amount of time is the current interval timeout minus the |
| current decrementer value. */ |
| void |
| __reset_spu_decr (int val) |
| { |
| |
| /* The interrupt occurs when the msb goes from 0 to 1 or when the decrementer |
| goes from 0 to -1. To be precisely accurate we should set the timer to |
| the intverval -1, unless the interval passed in is 0 in which case it |
| should be left at 0. */ |
| int enable_val = (__likely (val)) ? val - 1 : 0; |
| |
| /* Decrementer must be stopped before writing it - minimize the time |
| stopped. */ |
| unsigned mask = __disable_spu_decr (); |
| |
| /* Perform tb correction before resettting the decrementer. the corrected |
| value is the current timeout value minus the current decrementer value. |
| Occasionally the read returns 0 - a second read will clear this |
| condition. */ |
| spu_readch (SPU_RdDec); |
| int decval = spu_readch (SPU_RdDec); |
| /* Restart decrementer with next timeout val. */ |
| __enable_spu_decr (enable_val, mask); |
| |
| /* Update the timebase values before enabling for interrupts. */ |
| __spu_tb_val += __spu_tb_timeout - decval; |
| __spu_tb_timeout = enable_val; |
| } |
| |
| /* Update software timebase and timeout value for the 'next to expire' timer. |
| Called when starting a new timer so the timer list will have timeouts |
| relative to the current time. */ |
| static inline void |
| __update_spu_tb_val (void) |
| { |
| int elapsed = __spu_tb_timeout - spu_readch (SPU_RdDec); |
| #ifdef SPU_TIMER_DEBUG |
| if (elapsed < 0) |
| ABORT (); |
| #endif |
| __spu_tb_val += elapsed; |
| |
| /* Adjust the timeout for the timer next to expire. Note this could cause |
| the timeout to go negative, if it was just about to expire when we called |
| spu_timer_start. This is OK, since this can happen any time interrupts |
| are disabled. We just schedule an immediate timeout in this case. */ |
| if (__spu_timers_active) |
| { |
| __spu_timers_active->tmout -= elapsed; |
| if (__spu_timers_active->tmout < 0) |
| __spu_timers_active->tmout = 0; |
| } |
| } |
| |
| /* Add an allocated timer to the active list. The active list is sorted by |
| timeout value. The timer at the head of the list is the timer that will |
| expire next. The rest of the timers have a timeout value that is relative |
| to the timer ahead of it on the list. This relative value is determined |
| here, when the timer is added to the active list. When its position in the |
| list is found, the timer's timeout value is set to its interval minus the |
| sum of all the timeout values ahead of it. The timeout value for the timer |
| following the newly added timer is then adjusted to a new relative value. If |
| the newly added timer is at the head of the list, the decrementer is reset. |
| This function is called by SLIH to restart multiple timers (reset == 0) or |
| by spu_timer_start() to start a single timer (reset == 1). */ |
| void |
| __spu_timer_start (int id, int reset) |
| { |
| spu_timer_t *t; |
| spu_timer_t **pn; |
| spu_timer_t *start = &__spu_timers[id]; |
| unsigned tmout_time = 0; |
| unsigned my_intvl = start->intvl; |
| unsigned was_enabled = spu_readch (SPU_RdMachStat) & 0x1; |
| |
| spu_idisable (); |
| |
| t = __spu_timers_active; |
| pn = &__spu_timers_active; |
| |
| /* If the active list is empty, just add the timer with the timeout set to |
| the interval. Otherwise find the place in the list for the timer, setting |
| its timeout to its interval minus the sum of timeouts ahead of it. */ |
| start->state = SPU_TIMER_ACTIVE; |
| if (__likely (!t)) |
| { |
| __spu_timers_active = start; |
| start->next = NULL; |
| start->tmout = my_intvl; |
| } |
| else |
| { |
| |
| /* Update swtb and timeout val of the next timer, so all times are |
| relative to now. */ |
| if (reset) |
| __update_spu_tb_val (); |
| |
| while (t && (my_intvl >= (tmout_time + t->tmout))) |
| { |
| tmout_time += t->tmout; |
| pn = &t->next;; |
| t = t->next; |
| } |
| start->next = t; |
| start->tmout = my_intvl - tmout_time; |
| *pn = start; |
| |
| /* Adjust timeout for timer after us. */ |
| if (t) |
| t->tmout -= start->tmout; |
| } |
| |
| if (reset && (__spu_timers_active == start)) |
| __reset_spu_decr (__spu_timers_active->tmout); |
| |
| if (__unlikely (was_enabled)) |
| spu_ienable (); |
| } |
| |
| /* SLIH for decrementer. Manages software timebase and timers. |
| Called by SPU FLIH. Assumes decrementer is still running |
| (event not yet acknowledeged). */ |
| unsigned int |
| spu_clock_slih (unsigned status) |
| { |
| int decr_reset_val; |
| spu_timer_t *active, *handled; |
| unsigned was_enabled = spu_readch (SPU_RdMachStat) & 0x1; |
| |
| status &= ~MFC_DECREMENTER_EVENT; |
| |
| spu_idisable (); |
| |
| /* The decrementer has now expired. The decrementer event was acknowledged |
| in the FLIH but not disabled. The decrementer will continue to run while |
| we're running the clock/timer handler. The software clock keeps running, |
| and accounts for all the time spent running handlers. Add the current |
| timeout to the software timebase and set the timeout to DECR_MAX. This |
| allows the "clock read" code to continue to work while we're in here, and |
| gives us the most possible time to finish before another underflow. */ |
| __spu_tb_val += __spu_tb_timeout; |
| __spu_tb_timeout = DECR_MAX; |
| |
| /* For all timers that have the current timeout value, move them from the |
| active list to the handled list and call their handlers. Note that the |
| handled/stopped lists may be manipulated by the handlers if they wish to |
| stop/free the timers. Note that only the first expired timer will reflect |
| the real timeout value; the rest of the timers that had the same timeout |
| value will have a relative value of zero. */ |
| if (__spu_timers_active) |
| { |
| __spu_timers_active->tmout = 0; |
| while ((active = __spu_timers_active) |
| && (active->tmout <= TIMER_INTERVAL_WINDOW)) |
| { |
| __spu_timers_active = active->next; |
| active->next = __spu_timers_handled; |
| __spu_timers_handled = active; |
| active->state = SPU_TIMER_HANDLED; |
| (*active->func) (active->id); |
| } |
| } |
| |
| /* put the handled timers back on the list and restart decrementer. */ |
| while ((handled = __spu_timers_handled) != NULL) |
| { |
| __spu_timers_handled = handled->next; |
| __spu_timer_start (handled->id, 0); |
| } |
| |
| /* Reset the decrementer before returning. If we have any active timers, we |
| set it to the timeout value for the timer at the head of the list, else |
| the default clock value. */ |
| decr_reset_val = __spu_timers_active ? __spu_timers_active->tmout : CLOCK_START_VALUE; |
| |
| __reset_spu_decr (decr_reset_val); |
| |
| if (__likely (was_enabled)) |
| spu_ienable (); |
| |
| return status; |
| } |