switch.c

LINUX 2.6.17.4的源码

	 *     SPU by mapping the virtual pages assigned to
	 *     the SPU memory-mapped I/O (MMIO) for problem
	 *     state. TBD.
	 */
}

static inline void reset_switch_active(struct spu_state *csa, struct spu *spu)
{
	/* Restore, Step 74:
	 *     Reset the "context switch active" flag.
	 */
	clear_bit(SPU_CONTEXT_SWITCH_ACTIVE, &spu->flags);
	mb();
}

static inline void reenable_interrupts(struct spu_state *csa, struct spu *spu)
{
	/* Restore, Step 75:
	 *     Re-enable SPU interrupts.
	 */
	spin_lock_irq(&spu->register_lock);
	spu_int_mask_set(spu, 0, csa->priv1.int_mask_class0_RW);
	spu_int_mask_set(spu, 1, csa->priv1.int_mask_class1_RW);
	spu_int_mask_set(spu, 2, csa->priv1.int_mask_class2_RW);
	spin_unlock_irq(&spu->register_lock);
}

static int quiece_spu(struct spu_state *prev, struct spu *spu)
{
	/*
	 * Combined steps 2-18 of SPU context save sequence, which
	 * quiesce the SPU state (disable SPU execution, MFC command
	 * queues, decrementer, SPU interrupts, etc.).
	 *
	 * Returns      0 on success.
	 *              2 if failed step 2.
	 *              6 if failed step 6.
	 */

	if (check_spu_isolate(prev, spu)) {	/* Step 2. */
		return 2;
	}
	disable_interrupts(prev, spu);	        /* Step 3. */
	set_watchdog_timer(prev, spu);	        /* Step 4. */
	inhibit_user_access(prev, spu);	        /* Step 5. */
	if (check_spu_isolate(prev, spu)) {	/* Step 6. */
		return 6;
	}
	set_switch_pending(prev, spu);	        /* Step 7. */
	save_mfc_cntl(prev, spu);		/* Step 8. */
	save_spu_runcntl(prev, spu);	        /* Step 9. */
	save_mfc_sr1(prev, spu);	        /* Step 10. */
	save_spu_status(prev, spu);	        /* Step 11. */
	save_mfc_decr(prev, spu);	        /* Step 12. */
	halt_mfc_decr(prev, spu);	        /* Step 13. */
	save_timebase(prev, spu);		/* Step 14. */
	remove_other_spu_access(prev, spu);	/* Step 15. */
	do_mfc_mssync(prev, spu);	        /* Step 16. */
	issue_mfc_tlbie(prev, spu);	        /* Step 17. */
	handle_pending_interrupts(prev, spu);	/* Step 18. */

	return 0;
}

static void save_csa(struct spu_state *prev, struct spu *spu)
{
	/*
	 * Combine steps 19-44 of SPU context save sequence, which
	 * save regions of the privileged & problem state areas.
	 */

	save_mfc_queues(prev, spu);	/* Step 19. */
	save_ppu_querymask(prev, spu);	/* Step 20. */
	save_ppu_querytype(prev, spu);	/* Step 21. */
	save_mfc_csr_tsq(prev, spu);	/* Step 22. */
	save_mfc_csr_cmd(prev, spu);	/* Step 23. */
	save_mfc_csr_ato(prev, spu);	/* Step 24. */
	save_mfc_tclass_id(prev, spu);	/* Step 25. */
	set_mfc_tclass_id(prev, spu);	/* Step 26. */
	purge_mfc_queue(prev, spu);	/* Step 27. */
	wait_purge_complete(prev, spu);	/* Step 28. */
	save_mfc_slbs(prev, spu);	/* Step 29. */
	setup_mfc_sr1(prev, spu);	/* Step 30. */
	save_spu_npc(prev, spu);	/* Step 31. */
	save_spu_privcntl(prev, spu);	/* Step 32. */
	reset_spu_privcntl(prev, spu);	/* Step 33. */
	save_spu_lslr(prev, spu);	/* Step 34. */
	reset_spu_lslr(prev, spu);	/* Step 35. */
	save_spu_cfg(prev, spu);	/* Step 36. */
	save_pm_trace(prev, spu);	/* Step 37. */
	save_mfc_rag(prev, spu);	/* Step 38. */
	save_ppu_mb_stat(prev, spu);	/* Step 39. */
	save_ppu_mb(prev, spu);	        /* Step 40. */
	save_ppuint_mb(prev, spu);	/* Step 41. */
	save_ch_part1(prev, spu);	/* Step 42. */
	save_spu_mb(prev, spu);	        /* Step 43. */
	save_mfc_cmd(prev, spu);	/* Step 44. */
	reset_ch(prev, spu);	        /* Step 45. */
}

static void save_lscsa(struct spu_state *prev, struct spu *spu)
{
	/*
	 * Perform steps 46-57 of SPU context save sequence,
	 * which save regions of the local store and register
	 * file.
	 */

	resume_mfc_queue(prev, spu);	/* Step 46. */
	setup_mfc_slbs(prev, spu);	/* Step 47. */
	set_switch_active(prev, spu);	/* Step 48. */
	enable_interrupts(prev, spu);	/* Step 49. */
	save_ls_16kb(prev, spu);	/* Step 50. */
	set_spu_npc(prev, spu);	        /* Step 51. */
	set_signot1(prev, spu);		/* Step 52. */
	set_signot2(prev, spu);		/* Step 53. */
	send_save_code(prev, spu);	/* Step 54. */
	set_ppu_querymask(prev, spu);	/* Step 55. */
	wait_tag_complete(prev, spu);	/* Step 56. */
	wait_spu_stopped(prev, spu);	/* Step 57. */
}

static void harvest(struct spu_state *prev, struct spu *spu)
{
	/*
	 * Perform steps 2-25 of SPU context restore sequence,
	 * which resets an SPU either after a failed save, or
	 * when using SPU for first time.
	 */

	disable_interrupts(prev, spu);	        /* Step 2.  */
	inhibit_user_access(prev, spu);	        /* Step 3.  */
	terminate_spu_app(prev, spu);	        /* Step 4.  */
	set_switch_pending(prev, spu);	        /* Step 5.  */
	remove_other_spu_access(prev, spu);	/* Step 6.  */
	suspend_mfc(prev, spu);	                /* Step 7.  */
	wait_suspend_mfc_complete(prev, spu);	/* Step 8.  */
	if (!suspend_spe(prev, spu))	        /* Step 9.  */
		clear_spu_status(prev, spu);	/* Step 10. */
	do_mfc_mssync(prev, spu);	        /* Step 11. */
	issue_mfc_tlbie(prev, spu);	        /* Step 12. */
	handle_pending_interrupts(prev, spu);	/* Step 13. */
	purge_mfc_queue(prev, spu);	        /* Step 14. */
	wait_purge_complete(prev, spu);	        /* Step 15. */
	reset_spu_privcntl(prev, spu);	        /* Step 16. */
	reset_spu_lslr(prev, spu);              /* Step 17. */
	setup_mfc_sr1(prev, spu);	        /* Step 18. */
	invalidate_slbs(prev, spu);	        /* Step 19. */
	reset_ch_part1(prev, spu);	        /* Step 20. */
	reset_ch_part2(prev, spu);	        /* Step 21. */
	enable_interrupts(prev, spu);	        /* Step 22. */
	set_switch_active(prev, spu);	        /* Step 23. */
	set_mfc_tclass_id(prev, spu);	        /* Step 24. */
	resume_mfc_queue(prev, spu);	        /* Step 25. */
}

static void restore_lscsa(struct spu_state *next, struct spu *spu)
{
	/*
	 * Perform steps 26-40 of SPU context restore sequence,
	 * which restores regions of the local store and register
	 * file.
	 */

	set_watchdog_timer(next, spu);	        /* Step 26. */
	setup_spu_status_part1(next, spu);	/* Step 27. */
	setup_spu_status_part2(next, spu);	/* Step 28. */
	restore_mfc_rag(next, spu);	        /* Step 29. */
	setup_mfc_slbs(next, spu);	        /* Step 30. */
	set_spu_npc(next, spu);	                /* Step 31. */
	set_signot1(next, spu);	                /* Step 32. */
	set_signot2(next, spu);	                /* Step 33. */
	setup_decr(next, spu);	                /* Step 34. */
	setup_ppu_mb(next, spu);	        /* Step 35. */
	setup_ppuint_mb(next, spu);	        /* Step 36. */
	send_restore_code(next, spu);	        /* Step 37. */
	set_ppu_querymask(next, spu);	        /* Step 38. */
	wait_tag_complete(next, spu);	        /* Step 39. */
	wait_spu_stopped(next, spu);	        /* Step 40. */
}

static void restore_csa(struct spu_state *next, struct spu *spu)
{
	/*
	 * Combine steps 41-76 of SPU context restore sequence, which
	 * restore regions of the privileged & problem state areas.
	 */

	restore_spu_privcntl(next, spu);	/* Step 41. */
	restore_status_part1(next, spu);	/* Step 42. */
	restore_status_part2(next, spu);	/* Step 43. */
	restore_ls_16kb(next, spu);	        /* Step 44. */
	wait_tag_complete(next, spu);	        /* Step 45. */
	suspend_mfc(next, spu);	                /* Step 46. */
	wait_suspend_mfc_complete(next, spu);	/* Step 47. */
	issue_mfc_tlbie(next, spu);	        /* Step 48. */
	clear_interrupts(next, spu);	        /* Step 49. */
	restore_mfc_queues(next, spu);	        /* Step 50. */
	restore_ppu_querymask(next, spu);	/* Step 51. */
	restore_ppu_querytype(next, spu);	/* Step 52. */
	restore_mfc_csr_tsq(next, spu);	        /* Step 53. */
	restore_mfc_csr_cmd(next, spu);	        /* Step 54. */
	restore_mfc_csr_ato(next, spu);	        /* Step 55. */
	restore_mfc_tclass_id(next, spu);	/* Step 56. */
	set_llr_event(next, spu);	        /* Step 57. */
	restore_decr_wrapped(next, spu);	/* Step 58. */
	restore_ch_part1(next, spu);	        /* Step 59. */
	restore_ch_part2(next, spu);	        /* Step 60. */
	restore_spu_lslr(next, spu);	        /* Step 61. */
	restore_spu_cfg(next, spu);	        /* Step 62. */
	restore_pm_trace(next, spu);	        /* Step 63. */
	restore_spu_npc(next, spu);	        /* Step 64. */
	restore_spu_mb(next, spu);	        /* Step 65. */
	check_ppu_mb_stat(next, spu);	        /* Step 66. */
	check_ppuint_mb_stat(next, spu);	/* Step 67. */
	restore_mfc_slbs(next, spu);	        /* Step 68. */
	restore_mfc_sr1(next, spu);	        /* Step 69. */
	restore_other_spu_access(next, spu);	/* Step 70. */
	restore_spu_runcntl(next, spu);	        /* Step 71. */
	restore_mfc_cntl(next, spu);	        /* Step 72. */
	enable_user_access(next, spu);	        /* Step 73. */
	reset_switch_active(next, spu);	        /* Step 74. */
	reenable_interrupts(next, spu);	        /* Step 75. */
}

static int __do_spu_save(struct spu_state *prev, struct spu *spu)
{
	int rc;

	/*
	 * SPU context save can be broken into three phases:
	 *
	 *     (a) quiesce [steps 2-16].
	 *     (b) save of CSA, performed by PPE [steps 17-42]
	 *     (c) save of LSCSA, mostly performed by SPU [steps 43-52].
	 *
	 * Returns      0 on success.
	 *              2,6 if failed to quiece SPU
	 *              53 if SPU-side of save failed.
	 */

	rc = quiece_spu(prev, spu);	        /* Steps 2-16. */
	switch (rc) {
	default:
	case 2:
	case 6:
		harvest(prev, spu);
		return rc;
		break;
	case 0:
		break;
	}
	save_csa(prev, spu);	                /* Steps 17-43. */
	save_lscsa(prev, spu);	                /* Steps 44-53. */
	return check_save_status(prev, spu);	/* Step 54.     */
}

static int __do_spu_restore(struct spu_state *next, struct spu *spu)
{
	int rc;

	/*
	 * SPU context restore can be broken into three phases:
	 *
	 *    (a) harvest (or reset) SPU [steps 2-24].
	 *    (b) restore LSCSA [steps 25-40], mostly performed by SPU.
	 *    (c) restore CSA [steps 41-76], performed by PPE.
	 *
	 * The 'harvest' step is not performed here, but rather
	 * as needed below.
	 */

	restore_lscsa(next, spu);	        /* Steps 24-39. */
	rc = check_restore_status(next, spu);	/* Step 40.     */
	switch (rc) {
	default:
		/* Failed. Return now. */
		return rc;
		break;
	case 0:
		/* Fall through to next step. */
		break;
	}
	restore_csa(next, spu);

	return 0;
}

/**
 * spu_save - SPU context save, with locking.
 * @prev: pointer to SPU context save area, to be saved.
 * @spu: pointer to SPU iomem structure.
 *
 * Acquire locks, perform the save operation then return.
 */
int spu_save(struct spu_state *prev, struct spu *spu)
{
	int rc;

	acquire_spu_lock(spu);	        /* Step 1.     */
	rc = __do_spu_save(prev, spu);	/* Steps 2-53. */
	release_spu_lock(spu);
	if (rc) {
		panic("%s failed on SPU[%d], rc=%d.\n",
		      __func__, spu->number, rc);
	}
	return rc;
}

/**
 * spu_restore - SPU context restore, with harvest and locking.
 * @new: pointer to SPU context save area, to be restored.
 * @spu: pointer to SPU iomem structure.
 *
 * Perform harvest + restore, as we may not be coming
 * from a previous succesful save operation, and the
 * hardware state is unknown.
 */
int spu_restore(struct spu_state *new, struct spu *spu)
{
	int rc;

	acquire_spu_lock(spu);
	harvest(NULL, spu);
	spu->stop_code = 0;
	spu->dar = 0;
	spu->dsisr = 0;
	spu->slb_replace = 0;
	spu->class_0_pending = 0;
	rc = __do_spu_restore(new, spu);
	release_spu_lock(spu);
	if (rc) {
		panic("%s failed on SPU[%d] rc=%d.\n",
		       __func__, spu->number, rc);
	}
	return rc;
}

/**
 * spu_harvest - SPU harvest (reset) operation
 * @spu: pointer to SPU iomem structure.
 *
 * Perform SPU harvest (reset) operation.
 */
void spu_harvest(struct spu *spu)
{
	acquire_spu_lock(spu);
	harvest(NULL, spu);
	release_spu_lock(spu);
}

static void init_prob(struct spu_state *csa)
{
	csa->spu_chnlcnt_RW[9] = 1;
	csa->spu_chnlcnt_RW[21] = 16;
	csa->spu_chnlcnt_RW[23] = 1;
	csa->spu_chnlcnt_RW[28] = 1;
	csa->spu_chnlcnt_RW[30] = 1;
	csa->prob.spu_runcntl_RW = SPU_RUNCNTL_STOP;
}

static void init_priv1(struct spu_state *csa)
{
	/* Enable decode, relocate, tlbie response, master runcntl. */
	csa->priv1.mfc_sr1_RW = MFC_STATE1_LOCAL_STORAGE_DECODE_MASK |
	    MFC_STATE1_MASTER_RUN_CONTROL_MASK |
	    MFC_STATE1_PROBLEM_STATE_MASK |
	    MFC_STATE1_RELOCATE_MASK | MFC_STATE1_BUS_TLBIE_MASK;

	/* Set storage description.  */
	csa->priv1.mfc_sdr_RW = mfspr(SPRN_SDR1);

	/* Enable OS-specific set of interrupts. */
	csa->priv1.int_mask_class0_RW = CLASS0_ENABLE_DMA_ALIGNMENT_INTR |
	    CLASS0_ENABLE_INVALID_DMA_COMMAND_INTR |
	    CLASS0_ENABLE_SPU_ERROR_INTR;
	csa->priv1.int_mask_class1_RW = CLASS1_ENABLE_SEGMENT_FAULT_INTR |
	    CLASS1_ENABLE_STORAGE_FAULT_INTR;
	csa->priv1.int_mask_class2_RW = CLASS2_ENABLE_SPU_STOP_INTR |
	    CLASS2_ENABLE_SPU_HALT_INTR |
	    CLASS2_ENABLE_SPU_DMA_TAG_GROUP_COMPLETE_INTR;
}

static void init_priv2(struct spu_state *csa)
{
	csa->priv2.spu_lslr_RW = LS_ADDR_MASK;
	csa->priv2.mfc_control_RW = MFC_CNTL_RESUME_DMA_QUEUE |
	    MFC_CNTL_NORMAL_DMA_QUEUE_OPERATION |
	    MFC_CNTL_DMA_QUEUES_EMPTY_MASK;
}

/**
 * spu_alloc_csa - allocate and initialize an SPU context save area.
 *
 * Allocate and initialize the contents of an SPU context save area.
 * This includes enabling address translation, interrupt masks, etc.,
 * as appropriate for the given OS environment.
 *
 * Note that storage for the 'lscsa' is allocated separately,
 * as it is by far the largest of the context save regions,
 * and may need to be pinned or otherwise specially aligned.
 */
void spu_init_csa(struct spu_state *csa)
{
	struct spu_lscsa *lscsa;
	unsigned char *p;

	if (!csa)
		return;
	memset(csa, 0, sizeof(struct spu_state));

	lscsa = vmalloc(sizeof(struct spu_lscsa));
	if (!lscsa)
		return;

	memset(lscsa, 0, sizeof(struct spu_lscsa));
	csa->lscsa = lscsa;
	csa->register_lock = SPIN_LOCK_UNLOCKED;

	/* Set LS pages reserved to allow for user-space mapping. */
	for (p = lscsa->ls; p < lscsa->ls + LS_SIZE; p += PAGE_SIZE)
		SetPageReserved(vmalloc_to_page(p));

	init_prob(csa);
	init_priv1(csa);
	init_priv2(csa);
}

void spu_fini_csa(struct spu_state *csa)
{
	/* Clear reserved bit before vfree. */
	unsigned char *p;
	for (p = csa->lscsa->ls; p < csa->lscsa->ls + LS_SIZE; p += PAGE_SIZE)
		ClearPageReserved(vmalloc_to_page(p));

	vfree(csa->lscsa);
}