Re: [PATCH v7 4/5] remoteproc: ingenic: Added remoteproc driver

[Suman Anna]

Hi Paul,

On 6/12/20 6:47 AM, Paul Cercueil wrote:
> Hi Suman,
>
> Le jeu. 11 juin 2020 Ã 19:21, Suman Anna <s-anna@xxxxxx> a Ãcrit :
> > Hi Paul,
> >
> > On 6/11/20 5:21 PM, Paul Cercueil wrote:
> > > Hi Suman,
> > >
> > > Le jeu. 11 juin 2020 Ã 16:47, Suman Anna <s-anna@xxxxxx> a Ãcrit :
> > > > Hi Paul,
> > > >
> > > > On 5/15/20 5:43 AM, Paul Cercueil wrote:
> > > > > This driver is used to boot, communicate with and load firmwares to 
> > > > > the
> > > > > MIPS co-processor found in the VPU hardware of the JZ47xx SoCs from
> > > > > Ingenic.
> > > >
> > > > I have a few comments w.r.t pm_runtime usage in this driver.
> > > >
> > > > > Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> > > > > Acked-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> > > > > ---
> > > > >
> > > > > Notes:
> > > > > ÂÂÂÂ v2: Remove exception for always-mapped memories
> > > > > ÂÂÂÂ v3: - Use clk_bulk API
> > > > > ÂÂÂÂÂÂÂÂ - Move device-managed code to its own patch [3/4]
> > > > > ÂÂÂÂÂÂÂÂ - Move devicetree table right above ingenic_rproc_driver
> > > > > ÂÂÂÂÂÂÂÂ - Removed #ifdef CONFIG_OF around devicetree table
> > > > > ÂÂÂÂÂÂÂÂ - Removed .owner = THIS_MODULE in ingenic_rproc_driver
> > > > > ÂÂÂÂÂÂÂÂ - Removed useless platform_set_drvdata()
> > > > > ÂÂÂÂ v4: - Add fix reported by Julia
> > > > > ÂÂÂÂÂÂÂÂ - Change Kconfig symbol to INGENIC_VPU_RPROC
> > > > > ÂÂÂÂÂÂÂÂ - Add documentation to struct vpu
> > > > > ÂÂÂÂÂÂÂÂ - disable_irq_nosync() -> disable_irq()
> > > > > ÂÂÂÂ v5: No change
> > > > > ÂÂÂÂ v6: Instead of prepare/unprepare callbacks, use PM runtime 
> > > > > callbacks
> > > > > ÂÂÂÂ v7: - Remove use of of_match_ptr()
> > > > > ÂÂÂÂÂÂÂÂ - Move Kconfig symbol so that it's in alphabetical order
> > > > > ÂÂÂÂÂÂÂÂ - Add missing doc for private structure field aux_base
> > > > > ÂÂÂÂÂÂÂÂ - Don't check for (len <= 0) in da_to_va()
> > > > > ÂÂÂÂÂÂÂÂ - Add missing \n in dev_info/dev_err messages
> > > > >
> > > > > Â drivers/remoteproc/KconfigÂÂÂÂÂÂÂÂ |ÂÂ 9 +
> > > > > Â drivers/remoteproc/MakefileÂÂÂÂÂÂÂ |ÂÂ 1 +
> > > > > Â drivers/remoteproc/ingenic_rproc.c | 280 
> > > > > +++++++++++++++++++++++++++++
> > > > > Â 3 files changed, 290 insertions(+)
> > > > > Â create mode 100644 drivers/remoteproc/ingenic_rproc.c
> > > > >
> > > > > diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> > > > > index fbaed079b299..c4d1731295eb 100644
> > > > > --- a/drivers/remoteproc/Kconfig
> > > > > +++ b/drivers/remoteproc/Kconfig
> > > > > @@ -23,6 +23,15 @@ config IMX_REMOTEPROC
> > > > > Â ÂÂÂÂÂÂÂ It's safe to say N here.
> > > > > Â +config INGENIC_VPU_RPROC
> > > > > +ÂÂÂ tristate "Ingenic JZ47xx VPU remoteproc support"
> > > > > +ÂÂÂ depends on MIPS || COMPILE_TEST
> > > > > +ÂÂÂ help
> > > > > +ÂÂÂÂÂ Say y or m here to support the VPU in the JZ47xx SoCs 
> > > > > from Ingenic.
> > > > > +
> > > > > +ÂÂÂÂÂ This can be either built-in or a loadable module.
> > > > > +ÂÂÂÂÂ If unsure say N.
> > > > > +
> > > > > Â config MTK_SCP
> > > > > ÂÂÂÂÂ tristate "Mediatek SCP support"
> > > > > ÂÂÂÂÂ depends on ARCH_MEDIATEK
> > > > > diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
> > > > > index 0effd3825035..e8b886e511f0 100644
> > > > > --- a/drivers/remoteproc/Makefile
> > > > > +++ b/drivers/remoteproc/Makefile
> > > > > @@ -10,6 +10,7 @@ remoteproc-yÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ += remoteproc_sysfs.o
> > > > > Â remoteproc-yÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ += remoteproc_virtio.o
> > > > > Â remoteproc-yÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ += remoteproc_elf_loader.o
> > > > > Â obj-$(CONFIG_IMX_REMOTEPROC)ÂÂÂÂÂÂÂ += imx_rproc.o
> > > > > +obj-$(CONFIG_INGENIC_VPU_RPROC)ÂÂÂÂÂÂÂ += ingenic_rproc.o
> > > > > Â obj-$(CONFIG_MTK_SCP)ÂÂÂÂÂÂÂÂÂÂÂ += mtk_scp.o mtk_scp_ipi.o
> > > > > Â obj-$(CONFIG_OMAP_REMOTEPROC)ÂÂÂÂÂÂÂ += omap_remoteproc.o
> > > > > Â obj-$(CONFIG_WKUP_M3_RPROC)ÂÂÂÂÂÂÂ += wkup_m3_rproc.o
> > > > > diff --git a/drivers/remoteproc/ingenic_rproc.c 
> > > > > b/drivers/remoteproc/ingenic_rproc.c
> > > > > new file mode 100644
> > > > > index 000000000000..189020d77b25
> > > > > --- /dev/null
> > > > > +++ b/drivers/remoteproc/ingenic_rproc.c
> > > > > @@ -0,0 +1,280 @@
> > > > > +// SPDX-License-Identifier: GPL-2.0+
> > > > > +/*
> > > > > + * Ingenic JZ47xx remoteproc driver
> > > > > + * Copyright 2019, Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> > > > > + */
> > > > > +
> > > > > +#include <linux/bitops.h>
> > > > > +#include <linux/clk.h>
> > > > > +#include <linux/err.h>
> > > > > +#include <linux/interrupt.h>
> > > > > +#include <linux/io.h>
> > > > > +#include <linux/module.h>
> > > > > +#include <linux/platform_device.h>
> > > > > +#include <linux/pm_runtime.h>
> > > > > +#include <linux/remoteproc.h>
> > > > > +
> > > > > +#include "remoteproc_internal.h"
> > > > > +
> > > > > +#define REG_AUX_CTRLÂÂÂÂÂÂÂ 0x0
> > > > > +#define REG_AUX_MSG_ACKÂÂÂÂÂÂÂ 0x10
> > > > > +#define REG_AUX_MSGÂÂÂÂÂÂÂ 0x14
> > > > > +#define REG_CORE_MSG_ACKÂÂÂ 0x18
> > > > > +#define REG_CORE_MSGÂÂÂÂÂÂÂ 0x1C
> > > > > +
> > > > > +#define AUX_CTRL_SLEEPÂÂÂÂÂÂÂ BIT(31)
> > > > > +#define AUX_CTRL_MSG_IRQ_ENÂÂÂ BIT(3)
> > > > > +#define AUX_CTRL_NMI_RESETSÂÂÂ BIT(2)
> > > > > +#define AUX_CTRL_NMIÂÂÂÂÂÂÂ BIT(1)
> > > > > +#define AUX_CTRL_SW_RESETÂÂÂ BIT(0)
> > > > > +
> > > > > +struct vpu_mem_map {
> > > > > +ÂÂÂ const char *name;
> > > > > +ÂÂÂ unsigned int da;
> > > > > +};
> > > > > +
> > > > > +struct vpu_mem_info {
> > > > > +ÂÂÂ const struct vpu_mem_map *map;
> > > > > +ÂÂÂ unsigned long len;
> > > > > +ÂÂÂ void __iomem *base;
> > > > > +};
> > > > > +
> > > > > +static const struct vpu_mem_map vpu_mem_map[] = {
> > > > > +ÂÂÂ { "tcsm0", 0x132b0000 },
> > > > > +ÂÂÂ { "tcsm1", 0xf4000000 },
> > > > > + { "sram", 0x132f0000 },
> > > > > +};
> > > > > +
> > > > > +/**
> > > > > + * struct vpu - Ingenic VPU remoteproc private structure
> > > > > + * @irq: interrupt number
> > > > > + * @clks: pointers to the VPU and AUX clocks
> > > > > + * @aux_base: raw pointer to the AUX interface registers
> > > > > + * @mem_info: array of struct vpu_mem_info, which contain the 
> > > > > mapping info of
> > > > > + *ÂÂÂÂÂÂÂÂÂÂÂ each of the external memories
> > > > > + * @dev: private pointer to the device
> > > > > + */
> > > > > +struct vpu {
> > > > > +ÂÂÂ int irq;
> > > > > +ÂÂÂ struct clk_bulk_data clks[2];
> > > > > +ÂÂÂ void __iomem *aux_base;
> > > > > +ÂÂÂ struct vpu_mem_info mem_info[ARRAY_SIZE(vpu_mem_map)];
> > > > > +ÂÂÂ struct device *dev;
> > > > > +};
> > > > > +
> > > > > +static int ingenic_rproc_start(struct rproc *rproc)
> > > > > +{
> > > > > +ÂÂÂ struct vpu *vpu = rproc->priv;
> > > > > +ÂÂÂ u32 ctrl;
> > > > > +
> > > > > +ÂÂÂ enable_irq(vpu->irq);
> > > > > +
> > > > > +ÂÂÂ /* Reset the AUX and enable message IRQ */
> > > > > +ÂÂÂ ctrl = AUX_CTRL_NMI_RESETS | AUX_CTRL_NMI | AUX_CTRL_MSG_IRQ_EN;
> > > > > +ÂÂÂ writel(ctrl, vpu->aux_base + REG_AUX_CTRL);
> > > > > +
> > > > > +ÂÂÂ return 0;
> > > > > +}
> > > > > +
> > > > > +static int ingenic_rproc_stop(struct rproc *rproc)
> > > > > +{
> > > > > +ÂÂÂ struct vpu *vpu = rproc->priv;
> > > > > +
> > > > > +ÂÂÂ disable_irq(vpu->irq);
> > > > > +
> > > > > +ÂÂÂ /* Keep AUX in reset mode */
> > > > > +ÂÂÂ writel(AUX_CTRL_SW_RESET, vpu->aux_base + REG_AUX_CTRL);
> > > > > +
> > > > > +ÂÂÂ return 0;
> > > > > +}
> > > > > +
> > > > > +static void ingenic_rproc_kick(struct rproc *rproc, int vqid)
> > > > > +{
> > > > > +ÂÂÂ struct vpu *vpu = rproc->priv;
> > > > > +
> > > > > +ÂÂÂ writel(vqid, vpu->aux_base + REG_CORE_MSG);
> > > > > +}
> > > > > +
> > > > > +static void *ingenic_rproc_da_to_va(struct rproc *rproc, u64 
> > > > > da, size_t len)
> > > > > +{
> > > > > +ÂÂÂ struct vpu *vpu = rproc->priv;
> > > > > +ÂÂÂ void __iomem *va = NULL;
> > > > > +ÂÂÂ unsigned int i;
> > > > > +
> > > > > +ÂÂÂ for (i = 0; i < ARRAY_SIZE(vpu_mem_map); i++) {
> > > > > +ÂÂÂÂÂÂÂ const struct vpu_mem_info *info = &vpu->mem_info[i];
> > > > > +ÂÂÂÂÂÂÂ const struct vpu_mem_map *map = info->map;
> > > > > +
> > > > > +ÂÂÂÂÂÂÂ if (da >= map->da && (da + len) < (map->da + info->len)) {
> > > > > +ÂÂÂÂÂÂÂÂÂÂÂ va = info->base + (da - map->da);
> > > > > +ÂÂÂÂÂÂÂÂÂÂÂ break;
> > > > > +ÂÂÂÂÂÂÂ }
> > > > > +ÂÂÂ }
> > > > > +
> > > > > +ÂÂÂ return (__force void *)va;
> > > > > +}
> > > > > +
> > > > > +static struct rproc_ops ingenic_rproc_ops = {
> > > > > +ÂÂÂ .start = ingenic_rproc_start,
> > > > > +ÂÂÂ .stop = ingenic_rproc_stop,
> > > > > +ÂÂÂ .kick = ingenic_rproc_kick,
> > > > > +ÂÂÂ .da_to_va = ingenic_rproc_da_to_va,
> > > > > +};
> > > > > +
> > > > > +static irqreturn_t vpu_interrupt(int irq, void *data)
> > > > > +{
> > > > > +ÂÂÂ struct rproc *rproc = data;
> > > > > +ÂÂÂ struct vpu *vpu = rproc->priv;
> > > > > +ÂÂÂ u32 vring;
> > > > > +
> > > > > +ÂÂÂ vring = readl(vpu->aux_base + REG_AUX_MSG);
> > > > > +
> > > > > +ÂÂÂ /* Ack the interrupt */
> > > > > +ÂÂÂ writel(0, vpu->aux_base + REG_AUX_MSG_ACK);
> > > > > +
> > > > > +ÂÂÂ return rproc_vq_interrupt(rproc, vring);
> > > > > +}
> > > > > +
> > > > > +static void ingenic_rproc_disable_clks(void *data)
> > > > > +{
> > > > > +ÂÂÂ struct vpu *vpu = data;
> > > > > +
> > > > > +ÂÂÂ pm_runtime_resume(vpu->dev);
> > > > > +ÂÂÂ pm_runtime_disable(vpu->dev);
> > > > > +
> > > > > +ÂÂÂ clk_bulk_disable_unprepare(ARRAY_SIZE(vpu->clks), vpu->clks);
> > > > > +}
> > > > > +
> > > > > +static int ingenic_rproc_probe(struct platform_device *pdev)
> > > > > +{
> > > > > +ÂÂÂ struct device *dev = &pdev->dev;
> > > > > +ÂÂÂ struct resource *mem;
> > > > > +ÂÂÂ struct rproc *rproc;
> > > > > +ÂÂÂ struct vpu *vpu;
> > > > > +ÂÂÂ unsigned int i;
> > > > > +ÂÂÂ int ret;
> > > > > +
> > > > > +ÂÂÂ rproc = devm_rproc_alloc(dev, "ingenic-vpu",
> > > > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ &ingenic_rproc_ops, NULL, sizeof(*vpu));
> > > > > +ÂÂÂ if (!rproc)
> > > > > +ÂÂÂÂÂÂÂ return -ENOMEM;
> > > > > +
> > > > > +ÂÂÂ vpu = rproc->priv;
> > > > > +ÂÂÂ vpu->dev = &pdev->dev;
> > > > > +ÂÂÂ platform_set_drvdata(pdev, vpu);
> > > > > +
> > > > > +ÂÂÂ mem = platform_get_resource_byname(pdev, IORESOURCE_MEM, "aux");
> > > > > +ÂÂÂ vpu->aux_base = devm_ioremap_resource(dev, mem);
> > > > > +ÂÂÂ if (IS_ERR(vpu->aux_base)) {
> > > > > +ÂÂÂÂÂÂÂ dev_err(dev, "Failed to ioremap\n");
> > > > > +ÂÂÂÂÂÂÂ return PTR_ERR(vpu->aux_base);
> > > > > +ÂÂÂ }
> > > > > +
> > > > > +ÂÂÂ for (i = 0; i < ARRAY_SIZE(vpu_mem_map); i++) {
> > > > > +ÂÂÂÂÂÂÂ mem = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > > > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ vpu_mem_map[i].name);
> > > > > +
> > > > > +ÂÂÂÂÂÂÂ vpu->mem_info[i].base = devm_ioremap_resource(dev, mem);
> > > > > +ÂÂÂÂÂÂÂ if (IS_ERR(vpu->mem_info[i].base)) {
> > > > > +ÂÂÂÂÂÂÂÂÂÂÂ ret = PTR_ERR(vpu->mem_info[i].base);
> > > > > +ÂÂÂÂÂÂÂÂÂÂÂ dev_err(dev, "Failed to ioremap\n");
> > > > > +ÂÂÂÂÂÂÂÂÂÂÂ return ret;
> > > > > +ÂÂÂÂÂÂÂ }
> > > > > +
> > > > > +ÂÂÂÂÂÂÂ vpu->mem_info[i].len = resource_size(mem);
> > > > > +ÂÂÂÂÂÂÂ vpu->mem_info[i].map = &vpu_mem_map[i];
> > > > > +ÂÂÂ }
> > > > > +
> > > > > +ÂÂÂ vpu->clks[0].id = "vpu";
> > > > > +ÂÂÂ vpu->clks[1].id = "aux";
> > > > > +
> > > > > +ÂÂÂ ret = devm_clk_bulk_get(dev, ARRAY_SIZE(vpu->clks), vpu->clks);
> > > > > +ÂÂÂ if (ret) {
> > > > > +ÂÂÂÂÂÂÂ dev_err(dev, "Failed to get clocks\n");
> > > > > +ÂÂÂÂÂÂÂ return ret;
> > > > > +ÂÂÂ }
> > > > > +
> > > > > +ÂÂÂ vpu->irq = platform_get_irq(pdev, 0);
> > > > > +ÂÂÂ if (vpu->irq < 0)
> > > > > +ÂÂÂÂÂÂÂ return vpu->irq;
> > > > > +
> > > > > +ÂÂÂ ret = devm_request_irq(dev, vpu->irq, vpu_interrupt, 0, 
> > > > > "VPU", rproc);
> > > > > +ÂÂÂ if (ret < 0) {
> > > > > +ÂÂÂÂÂÂÂ dev_err(dev, "Failed to request IRQ\n");
> > > > > +ÂÂÂÂÂÂÂ return ret;
> > > > > +ÂÂÂ }
> > > > > +
> > > > > +ÂÂÂ disable_irq(vpu->irq);
> > > > > +
> > > > > +ÂÂÂ /* The clocks must be enabled for the firmware to be 
> > > > > loaded in TCSM */
> > > > > +ÂÂÂ ret = clk_bulk_prepare_enable(ARRAY_SIZE(vpu->clks), vpu->clks);
> > > > > +ÂÂÂ if (ret) {
> > > > > +ÂÂÂÂÂÂÂ dev_err(dev, "Unable to start clocks\n");
> > > > > +ÂÂÂÂÂÂÂ return ret;
> > > > > +ÂÂÂ }
> > > >
> > > > You are enabling the clocks directly here and also trying to 
> > > > manage them through pm_runtime callbacks again.
> > >
> > > Yes. The clocks need to be enabled in the probe.
> >
> > For the preferred non CONFIG_PM case now and lack of prepare/unprepare().
>
> I want to make it clear that I'm not against having .prepare/.unprepare, 
> but I want to see what maintainers have to say.

Yes, it is the solution though to meet all your needs if CONFIG_PM is 
not used in general.

> > > > > +
> > > > > +ÂÂÂ pm_runtime_irq_safe(dev);
> > > >
> > > > Nothing wrong with this, but this does take an additional 
> > > > reference count on the parent device (a bus device for you??), and 
> > > > also implies that your clk driver code can all run in atomic 
> > > > context so unless you have a strong reason, it is safe to drop this.
> > >
> > > The clock driver code can run in atomic context, it is guaranteed 
> > > by the clk API.
> >
> > OK.
> >
> > > > > +ÂÂÂ pm_runtime_set_active(dev);
> > > >
> > > > The get_sync below would have been sufficient if you had either 
> > > > limited the clk API above to just clk_prepare, or you could have 
> > > > moved the whole clk API above into your runtime resume callback.
> > >
> > > You assume that pm_runtime_get() will enable the clocks, but that's 
> > > only true if CONFIG_PM is set.
> > >
> > > The reason the clocks are enabled in the probe, and 
> > > pm_runtime_set_active() is called, is that it works whether or not 
> > > CONFIG_PM is set.
> >
> > As I said, if the intention is to reflect the clocks active state in 
> > rpm status, then pm_runtime_get_noresume() does the job for you 
> > instead of get_sync(). pm_runtime_get_sync() typically does 3 things - 
> > increment the usage count, invoke your callbacks (enable clocks for 
> > you), and sets the status to active, with the last two steps optional 
> > depending on usage count.
>
> So pm_runtime_get_noresume() instead of pm_runtime_set_active() + 
> pm_runtime_get_sync()?

Its, pm_runtime_set_active() + pm_runtime_get_noresume().

They do exactly what you desire in the sequence, clocks are already 
enabled, so you set the status and increment the rpm usage count.

> > > > > +ÂÂÂ pm_runtime_enable(dev);
> > > > > +ÂÂÂ pm_runtime_get_sync(dev);
> > > >
> > > > If the intention was to increment the usage count with the above 
> > > > sequence, pm_runtime_get_noresume() is better. But dropping all of 
> > > > the above and just using get_sync would have been sufficient.
> > > >
> > > > > +ÂÂÂ pm_runtime_use_autosuspend(dev);
> > > >
> > > > I don't see any setting of the autosuspend delay (default value 
> > > > is 0). So, you might have as well just not used this at all, and 
> > > > just used pm_runtime_put() below.
> > >
> > > Autosuspend delay value can be set from userspace.
> >
> > Yes, but I don't see a specific purpose for it in your driver. Either 
> > you have remoteproc running (and so clocks enabled always), or you 
> > don't have a firmware loaded and want clocks disabled (not sure you 
> > would want to waste power for certain of amount of time).
>
> What I had in mind is that it would prevent the hardware from being 
> quickly disabled then re-enabled when switching firmwares. But it's not 
> like it takes a long time to stop/start the clock, so this could go 
> away, yes.

Also note that pm_runtime_put() is already asynchronous, so it doesn't 
happen right away.

> > > > > +
> > > > > +ÂÂÂ ret = devm_add_action_or_reset(dev, 
> > > > > ingenic_rproc_disable_clks, vpu);
> > > > > +ÂÂÂ if (ret) {
> > > > > +ÂÂÂÂÂÂÂ dev_err(dev, "Unable to register action\n");
> > > > > +ÂÂÂÂÂÂÂ goto out_pm_put;
> > > > > +ÂÂÂ }
> > > > > +
> > > > > +ÂÂÂ ret = devm_rproc_add(dev, rproc);
> > > > > +ÂÂÂ if (ret) {
> > > > > +ÂÂÂÂÂÂÂ dev_err(dev, "Failed to register remote processor\n");
> > > > > +ÂÂÂÂÂÂÂ goto out_pm_put;
> > > > > +ÂÂÂ }
> > > >
> > > > You are using auto-boot, so the firmware loading is an 
> > > > asynchronous event and most probably you would run through below 
> > > > sequence first, and end up disabling the clocks with an incorrect 
> > > > rpm status.
> > >
> > > The driver can auto-load the firmware, but that does not mean it 
> > > will. We actually don't do that, and load a task-specific firmware 
> > > onto the remote processor on demand.
> >
> > Yeah OK, depends on what is preferred by default. If it is more 
> > standard practise that the remoteproc is booted by userspace always, 
> > then I suggest setting auto_boot as false. But nothing wrong with 
> > expecting to boot by default with a starting firmware.
>
> Ok, I didn't know there was a way to disable auto-boot.

Yes, you can just set the rproc->auto_boot = false after rproc_alloc() 
and before rproc_add(). Again, it depends on what you desire. I have 
seen some rproc drivers set this actually based on a DT flag.

> > > > > +
> > > > > +out_pm_put:
> > > > > +ÂÂÂ pm_runtime_put_autosuspend(dev);
> > > >
> > > > And finally, with the remoteproc core rpm patch, this would all 
> > > > have been unnecessary.
> > > >
> > > > > +
> > > > > +ÂÂÂ return ret;
> > > > > +}
> > > > > +
> > > > > +static const struct of_device_id ingenic_rproc_of_matches[] = {
> > > > > +ÂÂÂ { .compatible = "ingenic,jz4770-vpu-rproc", },
> > > > > +ÂÂÂ {}
> > > > > +};
> > > > > +MODULE_DEVICE_TABLE(of, ingenic_rproc_of_matches);
> > > > > +
> > > > > +static int __maybe_unused ingenic_rproc_suspend(struct device *dev)
> > > > > +{
> > > > > +ÂÂÂ struct vpu *vpu = dev_get_drvdata(dev);
> > > > > +
> > > > > +ÂÂÂ clk_bulk_disable(ARRAY_SIZE(vpu->clks), vpu->clks);
> > > > > +
> > > > > +ÂÂÂ return 0;
> > > > > +}
> > > > > +
> > > > > +static int __maybe_unused ingenic_rproc_resume(struct device *dev)
> > > > > +{
> > > > > +ÂÂÂ struct vpu *vpu = dev_get_drvdata(dev);
> > > > > +
> > > > > +ÂÂÂ return clk_bulk_enable(ARRAY_SIZE(vpu->clks), vpu->clks);
> > > > > +}
> > > > > +
> > > > > +static const struct dev_pm_ops __maybe_unused ingenic_rproc_pm = {
> > > > > +ÂÂÂ SET_RUNTIME_PM_OPS(ingenic_rproc_suspend, 
> > > > > ingenic_rproc_resume, NULL)
> > > > > +};
> > > > > +
> > > > > +static struct platform_driver ingenic_rproc_driver = {
> > > > > +ÂÂÂ .probe = ingenic_rproc_probe,
> > > > > +ÂÂÂ .driver = {
> > > > > +ÂÂÂÂÂÂÂ .name = "ingenic-vpu",
> > > > > +#ifdef CONFIG_PM
> > > >
> > > > Not sure why you would want to maintain this conditional, because 
> > > > runtime_pm is a core dependency now for your driver to work properly.
> > >
> > > No, it is not - the driver works perfectly fine with CONFIG_PM 
> > > being disabled, and having a hardcoded dependency on CONFIG_PM is 
> > > not something we want.
> >
> > OK, so if IIUC, in general CONFIG_PM is not a typical usage for your 
> > MIPS platforms. Your driver is the first non-ARM remoteproc driver :), 
> > CONFIG_PM is almost a given on most ARM platforms.
> >
> > So, I fail to see how your clocks can stay disabled then when 
> > CONFIG_PM=n if the remoteproc fails to load with the current code, 
> > which was your primary argument for using prepare/unprepare (based on 
> > comments on prior versions). It looks to me that your needs are indeed 
> > better suited with the prepare/unprepare ops as in your initial series.
>
> Yes, I find the rpm in remoteproc core solution more elegant, but that 
> doesn't work as well for me in the CONFIG_PM=n case.
>
> > And in the case of CONFIG_PM=y, you have three levels of code that 
> > enables the clocks (the bare clk API, the pm_runtime_get in probe, and 
> > the pm_runtime_get in the remoteproc core). Depending on the rpm 
> > status, it may or may not invoke the callbacks.
>
> pm_runtime_get() in the probe won't call pm_resume, since the rpm status 
> is marked as active with pm_runtime_set_active(), so the clocks are 
> enabled only once in the probe. 

Right, that's what I meant by last sentence above.

And even if the remoteproc core calls
> pm_runtime_get() in the middle of the probe (why would it?) it would 
> still work fine since the clock enable/disable API is reference-counted.

Yeah, mostly it won't happen because of the firmware_class loading, and 
you will run through the end of your probe before you get loaded.

So, how critical is this disabling clocks feature, because it doesn't 
work in your preferred CONFIG_PM=n case. And if the most common way for 
you is to load and unload from userspace anyway, you can just manage the 
clocks in probe and remove, and rely on modprobe or sysfs bind/unbind to 
ensure the clocks stay disabled.

regards
Suman

> Cheers,
> -Paul
>
> > regards
> > Suman
> >
> > > Cheers,
> > > -Paul
> > >
> > > > regards
> > > > Suman
> > > >
> > > > > +ÂÂÂÂÂÂÂ .pm = &ingenic_rproc_pm,
> > > > > +#endif
> > > > > +ÂÂÂÂÂÂÂ .of_match_table = ingenic_rproc_of_matches,
> > > > > +ÂÂÂ },
> > > > > +};
> > > > > +module_platform_driver(ingenic_rproc_driver);
> > > > > +
> > > > > +MODULE_LICENSE("GPL");
> > > > > +MODULE_AUTHOR("Paul Cercueil <paul@xxxxxxxxxxxxxxx>");
> > > > > +MODULE_DESCRIPTION("Ingenic JZ47xx Remote Processor control driver");