Re: [PATCHv6 12/14] remoteproc/omap: add support for runtime auto-suspend/resume
From: Tero Kristo
Date: Wed Feb 19 2020 - 14:07:40 EST
On 18/02/2020 00:18, Suman Anna wrote:
Hi Tero,
On 2/11/20 9:21 AM, Tero Kristo wrote:
From: Suman Anna <s-anna@xxxxxx>
This patch enhances the PM support in the OMAP remoteproc driver to
support the runtime auto-suspend. A remoteproc may not be required to
be running all the time, and typically will need to be active only
during certain usecases. As such, to save power, it should be turned
off during potential long periods of inactivity between usecases.
This suspend and resume of the device is a relatively heavy process
in terms of latencies, so a remoteproc should be suspended only after
a certain period of prolonged inactivity. The OMAP remoteproc driver
leverages the runtime pm framework's auto_suspend feature to accomplish
this functionality. This feature is automatically enabled when a remote
processor has successfully booted. The 'autosuspend_delay_ms' for each
device dictates the inactivity period/time to wait for before
suspending the device.
The runtime auto-suspend design relies on marking the last busy time
on every communication (virtqueue kick) to and from the remote processor.
When there has been no activity for 'autosuspend_delay_ms' time, the
runtime PM framework invokes the driver's runtime pm suspend callback
to suspend the device. The remote processor will be woken up on the
initiation of the next communication message through the runtime pm
resume callback. The current auto-suspend design also allows a remote
processor to deny a auto-suspend attempt, if it wishes to, by sending a
NACK response to the initial suspend request message sent to the remote
processor as part of the suspend process. The auto-suspend request is
also only attempted if the remote processor is idled and in standby at
the time of inactivity timer expiry. This choice is made to avoid
unnecessary messaging, and the auto-suspend is simply rescheduled to
be attempted again after a further lapse of autosuspend_delay_ms.
The runtime pm callbacks functionality in this patch reuses most of the
core logic from the suspend/resume support code, and make use of an
additional auto_suspend flag to differentiate the logic in common code
from system suspend. The system suspend/resume sequences are also updated
to reflect the proper pm_runtime statuses, and also to really perform a
suspend/resume only if the remoteproc has not been auto-suspended at the
time of request. The remote processor is left in suspended state on a
system resume if it has been auto-suspended before, and will be woken up
only when a usecase needs to run.
The OMAP remoteproc driver currently uses a default value of 10 seconds
for all OMAP remoteprocs, and a different value can be chosen either by
choosing a positive value for the 'ti,autosuspend-delay' under DT or by
This is now ti,autosuspend-delay-ms.
Right, can update that one.
updating the 'autosuspend_delay_ms' field at runtime through the sysfs
interface.
Eg: To use 25 seconds for IPU2 on DRA7xx,
echo 25000 > /sys/bus/platform/devices/55020000.ipu/power/autosuspend_delay_ms
The runtime suspend feature can also be similarly enabled or disabled by
writing 'auto' or 'on' to the device's 'control' power field. The default
is enabled.
Eg: To disable auto-suspend for IPU2 on DRA7xx SoC,
echo on > /sys/bus/platform/devices/55020000.ipu/power/control
Signed-off-by: Suman Anna <s-anna@xxxxxx>
[t-kristo@xxxxxx: converted to use ti-sysc instead of hwmod]
Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
---
drivers/remoteproc/omap_remoteproc.c | 189 +++++++++++++++++++++++++--
1 file changed, 178 insertions(+), 11 deletions(-)
diff --git a/drivers/remoteproc/omap_remoteproc.c b/drivers/remoteproc/omap_remoteproc.c
index e8d3520493e1..490a242130f9 100644
--- a/drivers/remoteproc/omap_remoteproc.c
+++ b/drivers/remoteproc/omap_remoteproc.c
@@ -22,6 +22,7 @@
#include <linux/of_device.h>
#include <linux/of_reserved_mem.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
#include <linux/dma-mapping.h>
#include <linux/remoteproc.h>
#include <linux/mailbox_client.h>
@@ -37,6 +38,9 @@
#include "omap_remoteproc.h"
#include "remoteproc_internal.h"
+/* default auto-suspend delay (ms) */
+#define DEFAULT_AUTOSUSPEND_DELAY 10000
+
/**
* struct omap_rproc_boot_data - boot data structure for the DSP omap rprocs
* @syscon: regmap handle for the system control configuration module
@@ -83,11 +87,14 @@ struct omap_rproc_timer {
* @num_mems: number of internal memory regions
* @num_timers: number of rproc timer(s)
* @timers: timer(s) info used by rproc
+ * @autosuspend_delay: auto-suspend delay value to be used for runtime pm
+ * @need_resume: if true a resume is needed in the system resume callback
* @rproc: rproc handle
* @reset: reset handle
* @pm_comp: completion primitive to sync for suspend response
* @fck: functional clock for the remoteproc
* @suspend_acked: state machine flag to store the suspend request ack
+ * @in_reset: if remoteproc is in reset or not
*/
struct omap_rproc {
struct mbox_chan *mbox;
@@ -97,11 +104,14 @@ struct omap_rproc {
int num_mems;
int num_timers;
struct omap_rproc_timer *timers;
+ int autosuspend_delay;
+ bool need_resume;
struct rproc *rproc;
struct reset_control *reset;
struct completion pm_comp;
struct clk *fck;
bool suspend_acked;
+ bool in_reset;
};
/**
@@ -403,11 +413,23 @@ static void omap_rproc_kick(struct rproc *rproc, int vqid)
struct device *dev = rproc->dev.parent;
int ret;
+ /* wake up the rproc before kicking it */
+ ret = pm_runtime_get_sync(dev);
+ if (WARN_ON(ret < 0)) {
+ dev_err(dev, "pm_runtime_get_sync() failed during kick, ret = %d\n",
+ ret);
+ pm_runtime_put_noidle(dev);
+ return;
+ }
+
/* send the index of the triggered virtqueue in the mailbox payload */
ret = mbox_send_message(oproc->mbox, (void *)vqid);
if (ret < 0)
dev_err(dev, "failed to send mailbox message, status = %d\n",
ret);
+
+ pm_runtime_mark_last_busy(dev);
+ pm_runtime_put_autosuspend(dev);
}
/**
@@ -498,6 +520,12 @@ static int omap_rproc_start(struct rproc *rproc)
goto disable_timers;
}
+ oproc->in_reset = false;
+
+ pm_runtime_get_sync(dev);
There are still some issues with this patch, namely the timers are not
shut down cleanly. I also prefer to keep the pm_runtime API usage
symmetric between start() and stop() and not use two different styles
(essentially follow the style from the downstream version). This should
help us in eliminating the in_reset variable
For timers, I did craft the internal patch fixing the runtime handling
couple of days back, so I can squash that into this one and post v7.
I don't quite get what you mean by the different styles / symmetricity
of the pm_runtime API usage, but it seems impossible to get rid of the
in_reset variable. Reset core does not have usecounting if the
reset_control_*_get_*_exclusive() variant is used, so we must handle the
usecounting of it internally within driver; otherwise we get timeouts.
Also, another issue is that driver removal calls pm_runtime_get() and
that causes a crash with omap_rproc_remove (rproc keep running while we
kill iommu etc.)
+ pm_runtime_mark_last_busy(dev);
+ pm_runtime_put_autosuspend(dev);
+
return 0;
disable_timers:
@@ -510,6 +538,7 @@ static int omap_rproc_start(struct rproc *rproc)
/* power off the remote processor */
static int omap_rproc_stop(struct rproc *rproc)
{
+ struct device *dev = rproc->dev.parent;
struct omap_rproc *oproc = rproc->priv;
int ret;
@@ -517,12 +546,20 @@ static int omap_rproc_stop(struct rproc *rproc)
if (ret)
return ret;
+ oproc->in_reset = true;
+
ret = omap_rproc_disable_timers(rproc, true);
if (ret)
return ret;
mbox_free_channel(oproc->mbox);
+ /*
+ * update the runtime pm states and status now that the remoteproc
+ * has stopped
+ */
+ pm_runtime_put_noidle(dev);
+
return 0;
}
@@ -579,17 +616,19 @@ static bool _is_rproc_in_standby(struct omap_rproc *oproc)
/* 1 sec is long enough time to let the remoteproc side suspend the device */
#define DEF_SUSPEND_TIMEOUT 1000
-static int _omap_rproc_suspend(struct rproc *rproc)
+static int _omap_rproc_suspend(struct rproc *rproc, bool auto_suspend)
{
struct device *dev = rproc->dev.parent;
struct omap_rproc *oproc = rproc->priv;
unsigned long to = msecs_to_jiffies(DEF_SUSPEND_TIMEOUT);
unsigned long ta = jiffies + to;
+ u32 suspend_msg = auto_suspend ?
+ RP_MBOX_SUSPEND_AUTO : RP_MBOX_SUSPEND_SYSTEM;
int ret;
reinit_completion(&oproc->pm_comp);
oproc->suspend_acked = false;
- ret = mbox_send_message(oproc->mbox, (void *)RP_MBOX_SUSPEND_SYSTEM);
+ ret = mbox_send_message(oproc->mbox, (void *)suspend_msg);
if (ret < 0) {
dev_err(dev, "PM mbox_send_message failed: %d\n", ret);
return ret;
@@ -622,6 +661,8 @@ static int _omap_rproc_suspend(struct rproc *rproc)
reset_control_assert(oproc->reset);
+ oproc->in_reset = true;
+
ret = omap_rproc_disable_timers(rproc, false);
if (ret) {
dev_err(dev, "disabling timers during suspend failed %d\n",
@@ -629,42 +670,79 @@ static int _omap_rproc_suspend(struct rproc *rproc)
goto enable_device;
}
+ /*
+ * IOMMUs would have to be disabled specifically for runtime suspend.
+ * They are handled automatically through System PM callbacks for
+ * regular system suspend
+ */
+ if (auto_suspend) {
+ ret = omap_iommu_domain_deactivate(rproc->domain);
+ if (ret) {
+ dev_err(dev, "iommu domain deactivate failed %d\n",
+ ret);
+ goto enable_timers;
+ }
+ }
+
return 0;
+enable_timers:
+ /* ignore errors on re-enabling code */
+ omap_rproc_enable_timers(rproc, false);
enable_device:
reset_control_deassert(oproc->reset);
return ret;
}
-static int _omap_rproc_resume(struct rproc *rproc)
+static int _omap_rproc_resume(struct rproc *rproc, bool auto_suspend)
{
struct device *dev = rproc->dev.parent;
struct omap_rproc *oproc = rproc->priv;
int ret;
+ /*
+ * IOMMUs would have to be enabled specifically for runtime resume.
+ * They would have been already enabled automatically through System
+ * PM callbacks for regular system resume
+ */
+ if (auto_suspend) {
+ ret = omap_iommu_domain_activate(rproc->domain);
+ if (ret) {
+ dev_err(dev, "omap_iommu activate failed %d\n", ret);
+ goto out;
+ }
+ }
+
/* boot address could be lost after suspend, so restore it */
if (oproc->boot_data) {
ret = omap_rproc_write_dsp_boot_addr(rproc);
if (ret) {
dev_err(dev, "boot address restore failed %d\n", ret);
- goto out;
+ goto suspend_iommu;
}
}
ret = omap_rproc_enable_timers(rproc, false);
if (ret) {
dev_err(dev, "enabling timers during resume failed %d\n", ret);
- goto out;
+ goto suspend_iommu;
}
- ret = reset_control_deassert(oproc->reset);
- if (ret) {
- dev_err(dev, "reset deassert failed %d\n", ret);
- goto disable_timers;
+ if (oproc->in_reset) {
+ ret = reset_control_deassert(oproc->reset);
+ if (ret) {
+ dev_err(dev, "reset deassert failed %d\n", ret);
+ goto disable_timers;
+ }
+
+ oproc->in_reset = false;
}
return 0;
+suspend_iommu:
+ if (auto_suspend)
+ omap_iommu_domain_deactivate(rproc->domain);
disable_timers:
omap_rproc_disable_timers(rproc, false);
@@ -676,6 +754,7 @@ static int __maybe_unused omap_rproc_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct rproc *rproc = platform_get_drvdata(pdev);
+ struct omap_rproc *oproc = rproc->priv;
int ret = 0;
mutex_lock(&rproc->lock);
@@ -690,13 +769,19 @@ static int __maybe_unused omap_rproc_suspend(struct device *dev)
goto out;
}
- ret = _omap_rproc_suspend(rproc);
+ ret = _omap_rproc_suspend(rproc, false);
if (ret) {
dev_err(dev, "suspend failed %d\n", ret);
goto out;
}
+ /*
+ * remoteproc is running at the time of system suspend, so remember
+ * it so as to wake it up during system resume
+ */
+ oproc->need_resume = true;
rproc->state = RPROC_SUSPENDED;
+
out:
mutex_unlock(&rproc->lock);
return ret;
@@ -706,6 +791,7 @@ static int __maybe_unused omap_rproc_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct rproc *rproc = platform_get_drvdata(pdev);
+ struct omap_rproc *oproc = rproc->priv;
int ret = 0;
mutex_lock(&rproc->lock);
@@ -717,17 +803,87 @@ static int __maybe_unused omap_rproc_resume(struct device *dev)
goto out;
}
- ret = _omap_rproc_resume(rproc);
+ /*
+ * remoteproc was auto-suspended at the time of system suspend,
+ * so no need to wake-up the processor (leave it in suspended
+ * state, will be woken up during a subsequent runtime_resume)
+ */
+ if (!oproc->need_resume)
+ goto out;
+
+ ret = _omap_rproc_resume(rproc, false);
if (ret) {
dev_err(dev, "resume failed %d\n", ret);
goto out;
}
+ oproc->need_resume = false;
rproc->state = RPROC_RUNNING;
+
+ pm_runtime_mark_last_busy(dev);
out:
mutex_unlock(&rproc->lock);
return ret;
}
+
+static int omap_rproc_runtime_suspend(struct device *dev)
+{
+ struct rproc *rproc = dev_get_drvdata(dev);
+ struct omap_rproc *oproc = rproc->priv;
+ int ret;
+
+ if (rproc->state == RPROC_CRASHED) {
+ dev_dbg(dev, "rproc cannot be runtime suspended when crashed!\n");
+ return -EBUSY;
+ }
+
+ if (WARN_ON(rproc->state != RPROC_RUNNING)) {
+ dev_err(dev, "rproc cannot be runtime suspended when not running!\n");
+ return -EBUSY;
+ }
+
+ /*
+ * do not even attempt suspend if the remote processor is not
+ * idled for runtime auto-suspend
+ */
+ if (!_is_rproc_in_standby(oproc)) {
+ ret = -EBUSY;
+ goto abort;
+ }
+
+ ret = _omap_rproc_suspend(rproc, true);
+ if (ret)
+ goto abort;
+
+ rproc->state = RPROC_SUSPENDED;
+ return 0;
+
+abort:
+ pm_runtime_mark_last_busy(dev);
+ return ret;
+}
+
+static int omap_rproc_runtime_resume(struct device *dev)
+{
+ struct rproc *rproc = dev_get_drvdata(dev);
+ int ret;
+
+ if (WARN_ON(rproc->state != RPROC_SUSPENDED &&
+ rproc->state != RPROC_OFFLINE)) {
+ dev_err(dev, "rproc cannot be runtime resumed if not suspended! state=%d\n", rproc->state);
+ return -EBUSY;
+ }
+
+ ret = _omap_rproc_resume(rproc, rproc->state == RPROC_SUSPENDED);
+ if (ret) {
+ dev_err(dev, "runtime resume failed %d\n", ret);
+ return ret;
+ }
+
+ rproc->state = RPROC_RUNNING;
+
+ return 0;
+}
#endif /* CONFIG_PM */
static const struct omap_rproc_mem_data ipu_mems[] = {
@@ -973,6 +1129,14 @@ static int omap_rproc_probe(struct platform_device *pdev)
}
init_completion(&oproc->pm_comp);
+ oproc->autosuspend_delay = DEFAULT_AUTOSUSPEND_DELAY;
+
+ of_property_read_u32(pdev->dev.of_node, "ti,autosuspend-delay-ms",
+ &oproc->autosuspend_delay);
+
+ pm_runtime_set_autosuspend_delay(&pdev->dev, oproc->autosuspend_delay);
+ pm_runtime_use_autosuspend(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
These are not unwound if there were failures in the code paths below.
Also, this gives a false status in sysfs as "suspended" in the case
where firmware is missing from the FS, and the device is never started.
This should be possible to fix.
-Tero
regards
Suman
oproc->fck = devm_clk_get(&pdev->dev, 0);
if (IS_ERR(oproc->fck)) {
@@ -1009,12 +1173,15 @@ static int omap_rproc_remove(struct platform_device *pdev)
rproc_del(rproc);
rproc_free(rproc);
of_reserved_mem_device_release(&pdev->dev);
+ pm_runtime_disable(&pdev->dev);
return 0;
}
static const struct dev_pm_ops omap_rproc_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(omap_rproc_suspend, omap_rproc_resume)
+ SET_RUNTIME_PM_OPS(omap_rproc_runtime_suspend,
+ omap_rproc_runtime_resume, NULL)
};
static struct platform_driver omap_rproc_driver = {
--
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