From b9c993aaf8962a99bc6da80918e30d582912c863 Mon Sep 17 00:00:00 2001 From: Axel Heider Date: Tue, 25 Oct 2022 17:33:43 +0200 Subject: hw/timer/imx_epit: improve comments Fix typos, add background information Signed-off-by: Axel Heider Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- hw/timer/imx_epit.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) (limited to 'hw/timer') diff --git a/hw/timer/imx_epit.c b/hw/timer/imx_epit.c index ec0fa44..2841fba 100644 --- a/hw/timer/imx_epit.c +++ b/hw/timer/imx_epit.c @@ -96,13 +96,14 @@ static void imx_epit_set_freq(IMXEPITState *s) } } +/* + * This is called both on hardware (device) reset and software reset. + */ static void imx_epit_reset(DeviceState *dev) { IMXEPITState *s = IMX_EPIT(dev); - /* - * Soft reset doesn't touch some bits; hard reset clears them - */ + /* Soft reset doesn't touch some bits; hard reset clears them */ s->cr &= (CR_EN|CR_ENMOD|CR_STOPEN|CR_DOZEN|CR_WAITEN|CR_DBGEN); s->sr = 0; s->lr = EPIT_TIMER_MAX; @@ -214,6 +215,7 @@ static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value, ptimer_transaction_begin(s->timer_cmp); ptimer_transaction_begin(s->timer_reload); + /* Update the frequency. Has been done already in case of a reset. */ if (!(s->cr & CR_SWR)) { imx_epit_set_freq(s); } @@ -254,7 +256,7 @@ static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value, break; case 1: /* SR - ACK*/ - /* writing 1 to OCIF clear the OCIF bit */ + /* writing 1 to OCIF clears the OCIF bit */ if (value & 0x01) { s->sr = 0; imx_epit_update_int(s); @@ -352,8 +354,18 @@ static void imx_epit_realize(DeviceState *dev, Error **errp) 0x00001000); sysbus_init_mmio(sbd, &s->iomem); + /* + * The reload timer keeps running when the peripheral is enabled. It is a + * kind of wall clock that does not generate any interrupts. The callback + * needs to be provided, but it does nothing as the ptimer already supports + * all necessary reloading functionality. + */ s->timer_reload = ptimer_init(imx_epit_reload, s, PTIMER_POLICY_LEGACY); + /* + * The compare timer is running only when the peripheral configuration is + * in a state that will generate compare interrupts. + */ s->timer_cmp = ptimer_init(imx_epit_cmp, s, PTIMER_POLICY_LEGACY); } -- cgit v1.1 From 018ee7948ff1df9cd98efee6e9d117eadb630cff Mon Sep 17 00:00:00 2001 From: Axel Heider Date: Mon, 31 Oct 2022 00:59:29 +0100 Subject: hw/timer/imx_epit: cleanup CR defines remove unused defines, add needed defines Signed-off-by: Axel Heider Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- hw/timer/imx_epit.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'hw/timer') diff --git a/hw/timer/imx_epit.c b/hw/timer/imx_epit.c index 2841fba..661e915 100644 --- a/hw/timer/imx_epit.c +++ b/hw/timer/imx_epit.c @@ -82,8 +82,8 @@ static void imx_epit_set_freq(IMXEPITState *s) uint32_t clksrc; uint32_t prescaler; - clksrc = extract32(s->cr, CR_CLKSRC_SHIFT, 2); - prescaler = 1 + extract32(s->cr, CR_PRESCALE_SHIFT, 12); + clksrc = extract32(s->cr, CR_CLKSRC_SHIFT, CR_CLKSRC_BITS); + prescaler = 1 + extract32(s->cr, CR_PRESCALE_SHIFT, CR_PRESCALE_BITS); s->freq = imx_ccm_get_clock_frequency(s->ccm, imx_epit_clocks[clksrc]) / prescaler; -- cgit v1.1 From 1ead962edf1297e223a039167429d4c986bfb90e Mon Sep 17 00:00:00 2001 From: Axel Heider Date: Sat, 19 Nov 2022 15:59:40 +0100 Subject: hw/timer/imx_epit: define SR_OCIF Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- hw/timer/imx_epit.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'hw/timer') diff --git a/hw/timer/imx_epit.c b/hw/timer/imx_epit.c index 661e915..f148868 100644 --- a/hw/timer/imx_epit.c +++ b/hw/timer/imx_epit.c @@ -66,7 +66,7 @@ static const IMXClk imx_epit_clocks[] = { */ static void imx_epit_update_int(IMXEPITState *s) { - if (s->sr && (s->cr & CR_OCIEN) && (s->cr & CR_EN)) { + if ((s->sr & SR_OCIF) && (s->cr & CR_OCIEN) && (s->cr & CR_EN)) { qemu_irq_raise(s->irq); } else { qemu_irq_lower(s->irq); @@ -256,9 +256,9 @@ static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value, break; case 1: /* SR - ACK*/ - /* writing 1 to OCIF clears the OCIF bit */ - if (value & 0x01) { - s->sr = 0; + /* writing 1 to SR.OCIF clears this bit and turns the interrupt off */ + if (value & SR_OCIF) { + s->sr = 0; /* SR.OCIF is the only bit in this register anyway */ imx_epit_update_int(s); } break; @@ -309,8 +309,8 @@ static void imx_epit_cmp(void *opaque) IMXEPITState *s = IMX_EPIT(opaque); DPRINTF("sr was %d\n", s->sr); - - s->sr = 1; + /* Set interrupt status bit SR.OCIF and update the interrupt state */ + s->sr |= SR_OCIF; imx_epit_update_int(s); } -- cgit v1.1 From 2ca267fd36a275c771528bd5ae50ae8406155ad9 Mon Sep 17 00:00:00 2001 From: Axel Heider Date: Tue, 25 Oct 2022 20:32:30 +0200 Subject: hw/timer/imx_epit: update interrupt state on CR write access The interrupt state can change due to: - reset clears both SR.OCIF and CR.OCIE - write to CR.EN or CR.OCIE Signed-off-by: Axel Heider Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- hw/timer/imx_epit.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) (limited to 'hw/timer') diff --git a/hw/timer/imx_epit.c b/hw/timer/imx_epit.c index f148868..7af3a8b 100644 --- a/hw/timer/imx_epit.c +++ b/hw/timer/imx_epit.c @@ -206,12 +206,20 @@ static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value, if (s->cr & CR_SWR) { /* handle the reset */ imx_epit_reset(DEVICE(s)); - /* - * TODO: could we 'break' here? following operations appear - * to duplicate the work imx_epit_reset() already did. - */ } + /* + * The interrupt state can change due to: + * - reset clears both SR.OCIF and CR.OCIE + * - write to CR.EN or CR.OCIE + */ + imx_epit_update_int(s); + + /* + * TODO: could we 'break' here for reset? following operations appear + * to duplicate the work imx_epit_reset() already did. + */ + ptimer_transaction_begin(s->timer_cmp); ptimer_transaction_begin(s->timer_reload); -- cgit v1.1 From 3d4615812578ca9f120e6e42237c90f56ca6db87 Mon Sep 17 00:00:00 2001 From: Axel Heider Date: Sat, 19 Nov 2022 17:09:59 +0100 Subject: hw/timer/imx_epit: hard reset initializes CR with 0 Signed-off-by: Axel Heider Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- hw/timer/imx_epit.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) (limited to 'hw/timer') diff --git a/hw/timer/imx_epit.c b/hw/timer/imx_epit.c index 7af3a8b..39f4722 100644 --- a/hw/timer/imx_epit.c +++ b/hw/timer/imx_epit.c @@ -99,12 +99,14 @@ static void imx_epit_set_freq(IMXEPITState *s) /* * This is called both on hardware (device) reset and software reset. */ -static void imx_epit_reset(DeviceState *dev) +static void imx_epit_reset(IMXEPITState *s, bool is_hard_reset) { - IMXEPITState *s = IMX_EPIT(dev); - /* Soft reset doesn't touch some bits; hard reset clears them */ - s->cr &= (CR_EN|CR_ENMOD|CR_STOPEN|CR_DOZEN|CR_WAITEN|CR_DBGEN); + if (is_hard_reset) { + s->cr = 0; + } else { + s->cr &= (CR_EN|CR_ENMOD|CR_STOPEN|CR_DOZEN|CR_WAITEN|CR_DBGEN); + } s->sr = 0; s->lr = EPIT_TIMER_MAX; s->cmp = 0; @@ -205,7 +207,7 @@ static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value, s->cr = value & 0x03ffffff; if (s->cr & CR_SWR) { /* handle the reset */ - imx_epit_reset(DEVICE(s)); + imx_epit_reset(s, false); } /* @@ -377,12 +379,18 @@ static void imx_epit_realize(DeviceState *dev, Error **errp) s->timer_cmp = ptimer_init(imx_epit_cmp, s, PTIMER_POLICY_LEGACY); } +static void imx_epit_dev_reset(DeviceState *dev) +{ + IMXEPITState *s = IMX_EPIT(dev); + imx_epit_reset(s, true); +} + static void imx_epit_class_init(ObjectClass *klass, void *data) { DeviceClass *dc = DEVICE_CLASS(klass); dc->realize = imx_epit_realize; - dc->reset = imx_epit_reset; + dc->reset = imx_epit_dev_reset; dc->vmsd = &vmstate_imx_timer_epit; dc->desc = "i.MX periodic timer"; } -- cgit v1.1 From 793a6ea0753562ab74ef86617415d3b50b9ec308 Mon Sep 17 00:00:00 2001 From: Axel Heider Date: Thu, 27 Oct 2022 15:09:58 +0200 Subject: hw/timer/imx_epit: factor out register write handlers Signed-off-by: Axel Heider Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- hw/timer/imx_epit.c | 207 ++++++++++++++++++++++++++++------------------------ 1 file changed, 113 insertions(+), 94 deletions(-) (limited to 'hw/timer') diff --git a/hw/timer/imx_epit.c b/hw/timer/imx_epit.c index 39f4722..e044275 100644 --- a/hw/timer/imx_epit.c +++ b/hw/timer/imx_epit.c @@ -191,129 +191,148 @@ static void imx_epit_reload_compare_timer(IMXEPITState *s) } } -static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value, - unsigned size) +static void imx_epit_write_cr(IMXEPITState *s, uint32_t value) { - IMXEPITState *s = IMX_EPIT(opaque); - uint64_t oldcr; - - DPRINTF("(%s, value = 0x%08x)\n", imx_epit_reg_name(offset >> 2), - (uint32_t)value); + uint32_t oldcr = s->cr; - switch (offset >> 2) { - case 0: /* CR */ - - oldcr = s->cr; - s->cr = value & 0x03ffffff; - if (s->cr & CR_SWR) { - /* handle the reset */ - imx_epit_reset(s, false); - } + s->cr = value & 0x03ffffff; - /* - * The interrupt state can change due to: - * - reset clears both SR.OCIF and CR.OCIE - * - write to CR.EN or CR.OCIE - */ - imx_epit_update_int(s); + if (s->cr & CR_SWR) { + /* handle the reset */ + imx_epit_reset(s, false); + } - /* - * TODO: could we 'break' here for reset? following operations appear - * to duplicate the work imx_epit_reset() already did. - */ + /* + * The interrupt state can change due to: + * - reset clears both SR.OCIF and CR.OCIE + * - write to CR.EN or CR.OCIE + */ + imx_epit_update_int(s); - ptimer_transaction_begin(s->timer_cmp); - ptimer_transaction_begin(s->timer_reload); + /* + * TODO: could we 'break' here for reset? following operations appear + * to duplicate the work imx_epit_reset() already did. + */ - /* Update the frequency. Has been done already in case of a reset. */ - if (!(s->cr & CR_SWR)) { - imx_epit_set_freq(s); - } + ptimer_transaction_begin(s->timer_cmp); + ptimer_transaction_begin(s->timer_reload); - if (s->freq && (s->cr & CR_EN) && !(oldcr & CR_EN)) { - if (s->cr & CR_ENMOD) { - if (s->cr & CR_RLD) { - ptimer_set_limit(s->timer_reload, s->lr, 1); - ptimer_set_limit(s->timer_cmp, s->lr, 1); - } else { - ptimer_set_limit(s->timer_reload, EPIT_TIMER_MAX, 1); - ptimer_set_limit(s->timer_cmp, EPIT_TIMER_MAX, 1); - } - } + /* Update the frequency. Has been done already in case of a reset. */ + if (!(s->cr & CR_SWR)) { + imx_epit_set_freq(s); + } - imx_epit_reload_compare_timer(s); - ptimer_run(s->timer_reload, 0); - if (s->cr & CR_OCIEN) { - ptimer_run(s->timer_cmp, 0); + if (s->freq && (s->cr & CR_EN) && !(oldcr & CR_EN)) { + if (s->cr & CR_ENMOD) { + if (s->cr & CR_RLD) { + ptimer_set_limit(s->timer_reload, s->lr, 1); + ptimer_set_limit(s->timer_cmp, s->lr, 1); } else { - ptimer_stop(s->timer_cmp); - } - } else if (!(s->cr & CR_EN)) { - /* stop both timers */ - ptimer_stop(s->timer_reload); - ptimer_stop(s->timer_cmp); - } else if (s->cr & CR_OCIEN) { - if (!(oldcr & CR_OCIEN)) { - imx_epit_reload_compare_timer(s); - ptimer_run(s->timer_cmp, 0); + ptimer_set_limit(s->timer_reload, EPIT_TIMER_MAX, 1); + ptimer_set_limit(s->timer_cmp, EPIT_TIMER_MAX, 1); } + } + + imx_epit_reload_compare_timer(s); + ptimer_run(s->timer_reload, 0); + if (s->cr & CR_OCIEN) { + ptimer_run(s->timer_cmp, 0); } else { ptimer_stop(s->timer_cmp); } + } else if (!(s->cr & CR_EN)) { + /* stop both timers */ + ptimer_stop(s->timer_reload); + ptimer_stop(s->timer_cmp); + } else if (s->cr & CR_OCIEN) { + if (!(oldcr & CR_OCIEN)) { + imx_epit_reload_compare_timer(s); + ptimer_run(s->timer_cmp, 0); + } + } else { + ptimer_stop(s->timer_cmp); + } - ptimer_transaction_commit(s->timer_cmp); - ptimer_transaction_commit(s->timer_reload); + ptimer_transaction_commit(s->timer_cmp); + ptimer_transaction_commit(s->timer_reload); +} + +static void imx_epit_write_sr(IMXEPITState *s, uint32_t value) +{ + /* writing 1 to SR.OCIF clears this bit and turns the interrupt off */ + if (value & SR_OCIF) { + s->sr = 0; /* SR.OCIF is the only bit in this register anyway */ + imx_epit_update_int(s); + } +} + +static void imx_epit_write_lr(IMXEPITState *s, uint32_t value) +{ + s->lr = value; + + ptimer_transaction_begin(s->timer_cmp); + ptimer_transaction_begin(s->timer_reload); + if (s->cr & CR_RLD) { + /* Also set the limit if the LRD bit is set */ + /* If IOVW bit is set then set the timer value */ + ptimer_set_limit(s->timer_reload, s->lr, s->cr & CR_IOVW); + ptimer_set_limit(s->timer_cmp, s->lr, 0); + } else if (s->cr & CR_IOVW) { + /* If IOVW bit is set then set the timer value */ + ptimer_set_count(s->timer_reload, s->lr); + } + /* + * Commit the change to s->timer_reload, so it can propagate. Otherwise + * the timer interrupt may not fire properly. The commit must happen + * before calling imx_epit_reload_compare_timer(), which reads + * s->timer_reload internally again. + */ + ptimer_transaction_commit(s->timer_reload); + imx_epit_reload_compare_timer(s); + ptimer_transaction_commit(s->timer_cmp); +} + +static void imx_epit_write_cmp(IMXEPITState *s, uint32_t value) +{ + s->cmp = value; + + ptimer_transaction_begin(s->timer_cmp); + imx_epit_reload_compare_timer(s); + ptimer_transaction_commit(s->timer_cmp); +} + +static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value, + unsigned size) +{ + IMXEPITState *s = IMX_EPIT(opaque); + + DPRINTF("(%s, value = 0x%08x)\n", imx_epit_reg_name(offset >> 2), + (uint32_t)value); + + switch (offset >> 2) { + case 0: /* CR */ + imx_epit_write_cr(s, (uint32_t)value); break; - case 1: /* SR - ACK*/ - /* writing 1 to SR.OCIF clears this bit and turns the interrupt off */ - if (value & SR_OCIF) { - s->sr = 0; /* SR.OCIF is the only bit in this register anyway */ - imx_epit_update_int(s); - } + case 1: /* SR */ + imx_epit_write_sr(s, (uint32_t)value); break; - case 2: /* LR - set ticks */ - s->lr = value; - - ptimer_transaction_begin(s->timer_cmp); - ptimer_transaction_begin(s->timer_reload); - if (s->cr & CR_RLD) { - /* Also set the limit if the LRD bit is set */ - /* If IOVW bit is set then set the timer value */ - ptimer_set_limit(s->timer_reload, s->lr, s->cr & CR_IOVW); - ptimer_set_limit(s->timer_cmp, s->lr, 0); - } else if (s->cr & CR_IOVW) { - /* If IOVW bit is set then set the timer value */ - ptimer_set_count(s->timer_reload, s->lr); - } - /* - * Commit the change to s->timer_reload, so it can propagate. Otherwise - * the timer interrupt may not fire properly. The commit must happen - * before calling imx_epit_reload_compare_timer(), which reads - * s->timer_reload internally again. - */ - ptimer_transaction_commit(s->timer_reload); - imx_epit_reload_compare_timer(s); - ptimer_transaction_commit(s->timer_cmp); + case 2: /* LR */ + imx_epit_write_lr(s, (uint32_t)value); break; case 3: /* CMP */ - s->cmp = value; - - ptimer_transaction_begin(s->timer_cmp); - imx_epit_reload_compare_timer(s); - ptimer_transaction_commit(s->timer_cmp); - + imx_epit_write_cmp(s, (uint32_t)value); break; default: qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%" HWADDR_PRIx "\n", TYPE_IMX_EPIT, __func__, offset); - break; } } + static void imx_epit_cmp(void *opaque) { IMXEPITState *s = IMX_EPIT(opaque); -- cgit v1.1 From e662449aa670bff938a011220593dd059b75e84b Mon Sep 17 00:00:00 2001 From: Axel Heider Date: Tue, 25 Oct 2022 12:33:42 +0200 Subject: hw/timer/imx_epit: remove explicit fields cnt and freq The CNT register is a read-only register. There is no need to store it's value, it can be calculated on demand. The calculated frequency is needed temporarily only. Note that this is a migration compatibility break for all boards types that use the EPIT peripheral. Signed-off-by: Axel Heider Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- hw/timer/imx_epit.c | 73 ++++++++++++++++++++--------------------------------- 1 file changed, 28 insertions(+), 45 deletions(-) (limited to 'hw/timer') diff --git a/hw/timer/imx_epit.c b/hw/timer/imx_epit.c index e044275..cf13496 100644 --- a/hw/timer/imx_epit.c +++ b/hw/timer/imx_epit.c @@ -73,27 +73,14 @@ static void imx_epit_update_int(IMXEPITState *s) } } -/* - * Must be called from within a ptimer_transaction_begin/commit block - * for both s->timer_cmp and s->timer_reload. - */ -static void imx_epit_set_freq(IMXEPITState *s) +static uint32_t imx_epit_get_freq(IMXEPITState *s) { - uint32_t clksrc; - uint32_t prescaler; - - clksrc = extract32(s->cr, CR_CLKSRC_SHIFT, CR_CLKSRC_BITS); - prescaler = 1 + extract32(s->cr, CR_PRESCALE_SHIFT, CR_PRESCALE_BITS); - - s->freq = imx_ccm_get_clock_frequency(s->ccm, - imx_epit_clocks[clksrc]) / prescaler; - - DPRINTF("Setting ptimer frequency to %u\n", s->freq); - - if (s->freq) { - ptimer_set_freq(s->timer_reload, s->freq); - ptimer_set_freq(s->timer_cmp, s->freq); - } + uint32_t clksrc = extract32(s->cr, CR_CLKSRC_SHIFT, CR_CLKSRC_BITS); + uint32_t prescaler = 1 + extract32(s->cr, CR_PRESCALE_SHIFT, CR_PRESCALE_BITS); + uint32_t f_in = imx_ccm_get_clock_frequency(s->ccm, imx_epit_clocks[clksrc]); + uint32_t freq = f_in / prescaler; + DPRINTF("ptimer frequency is %u\n", freq); + return freq; } /* @@ -110,32 +97,23 @@ static void imx_epit_reset(IMXEPITState *s, bool is_hard_reset) s->sr = 0; s->lr = EPIT_TIMER_MAX; s->cmp = 0; - s->cnt = 0; ptimer_transaction_begin(s->timer_cmp); ptimer_transaction_begin(s->timer_reload); - /* stop both timers */ + + /* + * The reset switches off the input clock, so even if the CR.EN is still + * set, the timers are no longer running. + */ + assert(imx_epit_get_freq(s) == 0); ptimer_stop(s->timer_cmp); ptimer_stop(s->timer_reload); - /* compute new frequency */ - imx_epit_set_freq(s); /* init both timers to EPIT_TIMER_MAX */ ptimer_set_limit(s->timer_cmp, EPIT_TIMER_MAX, 1); ptimer_set_limit(s->timer_reload, EPIT_TIMER_MAX, 1); - if (s->freq && (s->cr & CR_EN)) { - /* if the timer is still enabled, restart it */ - ptimer_run(s->timer_reload, 0); - } ptimer_transaction_commit(s->timer_cmp); ptimer_transaction_commit(s->timer_reload); } -static uint32_t imx_epit_update_count(IMXEPITState *s) -{ - s->cnt = ptimer_get_count(s->timer_reload); - - return s->cnt; -} - static uint64_t imx_epit_read(void *opaque, hwaddr offset, unsigned size) { IMXEPITState *s = IMX_EPIT(opaque); @@ -159,8 +137,7 @@ static uint64_t imx_epit_read(void *opaque, hwaddr offset, unsigned size) break; case 4: /* CNT */ - imx_epit_update_count(s); - reg_value = s->cnt; + reg_value = ptimer_get_count(s->timer_reload); break; default: @@ -179,7 +156,7 @@ static void imx_epit_reload_compare_timer(IMXEPITState *s) { if ((s->cr & (CR_EN | CR_OCIEN)) == (CR_EN | CR_OCIEN)) { /* if the compare feature is on and timers are running */ - uint32_t tmp = imx_epit_update_count(s); + uint32_t tmp = ptimer_get_count(s->timer_reload); uint64_t next; if (tmp > s->cmp) { /* It'll fire in this round of the timer */ @@ -193,6 +170,7 @@ static void imx_epit_reload_compare_timer(IMXEPITState *s) static void imx_epit_write_cr(IMXEPITState *s, uint32_t value) { + uint32_t freq = 0; uint32_t oldcr = s->cr; s->cr = value & 0x03ffffff; @@ -217,12 +195,19 @@ static void imx_epit_write_cr(IMXEPITState *s, uint32_t value) ptimer_transaction_begin(s->timer_cmp); ptimer_transaction_begin(s->timer_reload); - /* Update the frequency. Has been done already in case of a reset. */ + /* + * Update the frequency. In case of a reset the input clock was + * switched off, so this can be skipped. + */ if (!(s->cr & CR_SWR)) { - imx_epit_set_freq(s); + freq = imx_epit_get_freq(s); + if (freq) { + ptimer_set_freq(s->timer_reload, freq); + ptimer_set_freq(s->timer_cmp, freq); + } } - if (s->freq && (s->cr & CR_EN) && !(oldcr & CR_EN)) { + if (freq && (s->cr & CR_EN) && !(oldcr & CR_EN)) { if (s->cr & CR_ENMOD) { if (s->cr & CR_RLD) { ptimer_set_limit(s->timer_reload, s->lr, 1); @@ -356,15 +341,13 @@ static const MemoryRegionOps imx_epit_ops = { static const VMStateDescription vmstate_imx_timer_epit = { .name = TYPE_IMX_EPIT, - .version_id = 2, - .minimum_version_id = 2, + .version_id = 3, + .minimum_version_id = 3, .fields = (VMStateField[]) { VMSTATE_UINT32(cr, IMXEPITState), VMSTATE_UINT32(sr, IMXEPITState), VMSTATE_UINT32(lr, IMXEPITState), VMSTATE_UINT32(cmp, IMXEPITState), - VMSTATE_UINT32(cnt, IMXEPITState), - VMSTATE_UINT32(freq, IMXEPITState), VMSTATE_PTIMER(timer_reload, IMXEPITState), VMSTATE_PTIMER(timer_cmp, IMXEPITState), VMSTATE_END_OF_LIST() -- cgit v1.1 From 8d71beaf1e6b49266c4d98286f4ce6c874c998ae Mon Sep 17 00:00:00 2001 From: Axel Heider Date: Sun, 20 Nov 2022 20:05:25 +0100 Subject: hw/timer/imx_epit: fix compare timer handling - fix #1263 for CR writes - rework compare time handling - The compare timer has to run even if CR.OCIEN is not set, as SR.OCIF must be updated. - The compare timer fires exactly once when the compare value is less than the current value, but the reload values is less than the compare value. - The compare timer will never fire if the reload value is less than the compare value. Disable it in this case. Signed-off-by: Axel Heider [PMM: fixed minor style nits] Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- hw/timer/imx_epit.c | 184 ++++++++++++++++++++++++++++++++-------------------- 1 file changed, 112 insertions(+), 72 deletions(-) (limited to 'hw/timer') diff --git a/hw/timer/imx_epit.c b/hw/timer/imx_epit.c index cf13496..3a86978 100644 --- a/hw/timer/imx_epit.c +++ b/hw/timer/imx_epit.c @@ -6,6 +6,7 @@ * Originally written by Hans Jiang * Updated by Peter Chubb * Updated by Jean-Christophe Dubois + * Updated by Axel Heider * * This code is licensed under GPL version 2 or later. See * the COPYING file in the top-level directory. @@ -151,95 +152,134 @@ static uint64_t imx_epit_read(void *opaque, hwaddr offset, unsigned size) return reg_value; } -/* Must be called from ptimer_transaction_begin/commit block for s->timer_cmp */ -static void imx_epit_reload_compare_timer(IMXEPITState *s) +/* + * Must be called from a ptimer_transaction_begin/commit block for + * s->timer_cmp, but outside of a transaction block of s->timer_reload, + * so the proper counter value is read. + */ +static void imx_epit_update_compare_timer(IMXEPITState *s) { - if ((s->cr & (CR_EN | CR_OCIEN)) == (CR_EN | CR_OCIEN)) { - /* if the compare feature is on and timers are running */ - uint32_t tmp = ptimer_get_count(s->timer_reload); - uint64_t next; - if (tmp > s->cmp) { - /* It'll fire in this round of the timer */ - next = tmp - s->cmp; - } else { /* catch it next time around */ - next = tmp - s->cmp + ((s->cr & CR_RLD) ? EPIT_TIMER_MAX : s->lr); + uint64_t counter = 0; + bool is_oneshot = false; + /* + * The compare timer only has to run if the timer peripheral is active + * and there is an input clock, Otherwise it can be switched off. + */ + bool is_active = (s->cr & CR_EN) && imx_epit_get_freq(s); + if (is_active) { + /* + * Calculate next timeout for compare timer. Reading the reload + * counter returns proper results only if pending transactions + * on it are committed here. Otherwise stale values are be read. + */ + counter = ptimer_get_count(s->timer_reload); + uint64_t limit = ptimer_get_limit(s->timer_cmp); + /* + * The compare timer is a periodic timer if the limit is at least + * the compare value. Otherwise it may fire at most once in the + * current round. + */ + bool is_oneshot = (limit >= s->cmp); + if (counter >= s->cmp) { + /* The compare timer fires in the current round. */ + counter -= s->cmp; + } else if (!is_oneshot) { + /* + * The compare timer fires after a reload, as it is below the + * compare value already in this round. Note that the counter + * value calculated below can be above the 32-bit limit, which + * is legal here because the compare timer is an internal + * helper ptimer only. + */ + counter += limit - s->cmp; + } else { + /* + * The compare timer won't fire in this round, and the limit is + * set to a value below the compare value. This practically means + * it will never fire, so it can be switched off. + */ + is_active = false; } - ptimer_set_count(s->timer_cmp, next); } + + /* + * Set the compare timer and let it run, or stop it. This is agnostic + * of CR.OCIEN bit, as this bit affects interrupt generation only. The + * compare timer needs to run even if no interrupts are to be generated, + * because the SR.OCIF bit must be updated also. + * Note that the timer might already be stopped or be running with + * counter values. However, finding out when an update is needed and + * when not is not trivial. It's much easier applying the setting again, + * as this does not harm either and the overhead is negligible. + */ + if (is_active) { + ptimer_set_count(s->timer_cmp, counter); + ptimer_run(s->timer_cmp, is_oneshot ? 1 : 0); + } else { + ptimer_stop(s->timer_cmp); + } + } static void imx_epit_write_cr(IMXEPITState *s, uint32_t value) { - uint32_t freq = 0; uint32_t oldcr = s->cr; s->cr = value & 0x03ffffff; if (s->cr & CR_SWR) { - /* handle the reset */ + /* + * Reset clears CR.SWR again. It does not touch CR.EN, but the timers + * are still stopped because the input clock is disabled. + */ imx_epit_reset(s, false); - } - - /* - * The interrupt state can change due to: - * - reset clears both SR.OCIF and CR.OCIE - * - write to CR.EN or CR.OCIE - */ - imx_epit_update_int(s); - - /* - * TODO: could we 'break' here for reset? following operations appear - * to duplicate the work imx_epit_reset() already did. - */ - - ptimer_transaction_begin(s->timer_cmp); - ptimer_transaction_begin(s->timer_reload); - - /* - * Update the frequency. In case of a reset the input clock was - * switched off, so this can be skipped. - */ - if (!(s->cr & CR_SWR)) { + } else { + uint32_t freq; + uint32_t toggled_cr_bits = oldcr ^ s->cr; + /* re-initialize the limits if CR.RLD has changed */ + bool set_limit = toggled_cr_bits & CR_RLD; + /* set the counter if the timer got just enabled and CR.ENMOD is set */ + bool is_switched_on = (toggled_cr_bits & s->cr) & CR_EN; + bool set_counter = is_switched_on && (s->cr & CR_ENMOD); + + ptimer_transaction_begin(s->timer_cmp); + ptimer_transaction_begin(s->timer_reload); freq = imx_epit_get_freq(s); if (freq) { ptimer_set_freq(s->timer_reload, freq); ptimer_set_freq(s->timer_cmp, freq); } - } - if (freq && (s->cr & CR_EN) && !(oldcr & CR_EN)) { - if (s->cr & CR_ENMOD) { - if (s->cr & CR_RLD) { - ptimer_set_limit(s->timer_reload, s->lr, 1); - ptimer_set_limit(s->timer_cmp, s->lr, 1); - } else { - ptimer_set_limit(s->timer_reload, EPIT_TIMER_MAX, 1); - ptimer_set_limit(s->timer_cmp, EPIT_TIMER_MAX, 1); + if (set_limit || set_counter) { + uint64_t limit = (s->cr & CR_RLD) ? s->lr : EPIT_TIMER_MAX; + ptimer_set_limit(s->timer_reload, limit, set_counter ? 1 : 0); + if (set_limit) { + ptimer_set_limit(s->timer_cmp, limit, 0); } } - - imx_epit_reload_compare_timer(s); - ptimer_run(s->timer_reload, 0); - if (s->cr & CR_OCIEN) { - ptimer_run(s->timer_cmp, 0); + /* + * If there is an input clock and the peripheral is enabled, then + * ensure the wall clock timer is ticking. Otherwise stop the timers. + * The compare timer will be updated later. + */ + if (freq && (s->cr & CR_EN)) { + ptimer_run(s->timer_reload, 0); } else { - ptimer_stop(s->timer_cmp); - } - } else if (!(s->cr & CR_EN)) { - /* stop both timers */ - ptimer_stop(s->timer_reload); - ptimer_stop(s->timer_cmp); - } else if (s->cr & CR_OCIEN) { - if (!(oldcr & CR_OCIEN)) { - imx_epit_reload_compare_timer(s); - ptimer_run(s->timer_cmp, 0); + ptimer_stop(s->timer_reload); } - } else { - ptimer_stop(s->timer_cmp); + /* Commit changes to reload timer, so they can propagate. */ + ptimer_transaction_commit(s->timer_reload); + /* Update compare timer based on the committed reload timer value. */ + imx_epit_update_compare_timer(s); + ptimer_transaction_commit(s->timer_cmp); } - ptimer_transaction_commit(s->timer_cmp); - ptimer_transaction_commit(s->timer_reload); + /* + * The interrupt state can change due to: + * - reset clears both SR.OCIF and CR.OCIE + * - write to CR.EN or CR.OCIE + */ + imx_epit_update_int(s); } static void imx_epit_write_sr(IMXEPITState *s, uint32_t value) @@ -266,14 +306,10 @@ static void imx_epit_write_lr(IMXEPITState *s, uint32_t value) /* If IOVW bit is set then set the timer value */ ptimer_set_count(s->timer_reload, s->lr); } - /* - * Commit the change to s->timer_reload, so it can propagate. Otherwise - * the timer interrupt may not fire properly. The commit must happen - * before calling imx_epit_reload_compare_timer(), which reads - * s->timer_reload internally again. - */ + /* Commit the changes to s->timer_reload, so they can propagate. */ ptimer_transaction_commit(s->timer_reload); - imx_epit_reload_compare_timer(s); + /* Update the compare timer based on the committed reload timer value. */ + imx_epit_update_compare_timer(s); ptimer_transaction_commit(s->timer_cmp); } @@ -281,8 +317,9 @@ static void imx_epit_write_cmp(IMXEPITState *s, uint32_t value) { s->cmp = value; + /* Update the compare timer based on the committed reload timer value. */ ptimer_transaction_begin(s->timer_cmp); - imx_epit_reload_compare_timer(s); + imx_epit_update_compare_timer(s); ptimer_transaction_commit(s->timer_cmp); } @@ -322,6 +359,9 @@ static void imx_epit_cmp(void *opaque) { IMXEPITState *s = IMX_EPIT(opaque); + /* The cmp ptimer can't be running when the peripheral is disabled */ + assert(s->cr & CR_EN); + DPRINTF("sr was %d\n", s->sr); /* Set interrupt status bit SR.OCIF and update the interrupt state */ s->sr |= SR_OCIF; -- cgit v1.1 From a1e03956f4fb355d33a8a4d9f23ed35ccbed9ec9 Mon Sep 17 00:00:00 2001 From: Jean-Christophe Dubois Date: Tue, 20 Dec 2022 18:27:43 +0100 Subject: i.MX6UL: Add a specific GPT timer instance for the i.MX6UL The i.MX6UL doesn't support CLK_HIGH ou CLK_HIGH_DIV clock source. Signed-off-by: Jean-Christophe Dubois Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- hw/timer/imx_gpt.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'hw/timer') diff --git a/hw/timer/imx_gpt.c b/hw/timer/imx_gpt.c index 80b8302..7222b1b 100644 --- a/hw/timer/imx_gpt.c +++ b/hw/timer/imx_gpt.c @@ -115,6 +115,17 @@ static const IMXClk imx6_gpt_clocks[] = { CLK_HIGH, /* 111 reference clock */ }; +static const IMXClk imx6ul_gpt_clocks[] = { + CLK_NONE, /* 000 No clock source */ + CLK_IPG, /* 001 ipg_clk, 532MHz*/ + CLK_IPG_HIGH, /* 010 ipg_clk_highfreq */ + CLK_EXT, /* 011 External clock */ + CLK_32k, /* 100 ipg_clk_32k */ + CLK_NONE, /* 101 not defined */ + CLK_NONE, /* 110 not defined */ + CLK_NONE, /* 111 not defined */ +}; + static const IMXClk imx7_gpt_clocks[] = { CLK_NONE, /* 000 No clock source */ CLK_IPG, /* 001 ipg_clk, 532MHz*/ @@ -539,6 +550,13 @@ static void imx6_gpt_init(Object *obj) s->clocks = imx6_gpt_clocks; } +static void imx6ul_gpt_init(Object *obj) +{ + IMXGPTState *s = IMX_GPT(obj); + + s->clocks = imx6ul_gpt_clocks; +} + static void imx7_gpt_init(Object *obj) { IMXGPTState *s = IMX_GPT(obj); @@ -566,6 +584,12 @@ static const TypeInfo imx6_gpt_info = { .instance_init = imx6_gpt_init, }; +static const TypeInfo imx6ul_gpt_info = { + .name = TYPE_IMX6UL_GPT, + .parent = TYPE_IMX25_GPT, + .instance_init = imx6ul_gpt_init, +}; + static const TypeInfo imx7_gpt_info = { .name = TYPE_IMX7_GPT, .parent = TYPE_IMX25_GPT, @@ -577,6 +601,7 @@ static void imx_gpt_register_types(void) type_register_static(&imx25_gpt_info); type_register_static(&imx31_gpt_info); type_register_static(&imx6_gpt_info); + type_register_static(&imx6ul_gpt_info); type_register_static(&imx7_gpt_info); } -- cgit v1.1