[PATCH v3] mhi: pci_generic: Ensure device readiness before starting MHI

[PATCH v3] mhi: pci_generic: Ensure device readiness before starting MHI

[Loic Poulain]

The PCI device may have not been bound from cold boot and be in
undefined state, or simply not yet ready for MHI operations. This
change ensures that the MHI layer is reset to initial state and
ready for MHI initialization and power up.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
---
 v2: reset only if necessary
 v3: do not wait for MHI readiness in PBL context

 drivers/bus/mhi/pci_generic.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c
index c20f59e..87abd7c 100644
--- a/drivers/bus/mhi/pci_generic.c
+++ b/drivers/bus/mhi/pci_generic.c
@@ -17,6 +17,8 @@
 #include <linux/timer.h>
 #include <linux/workqueue.h>
 
+#include "core/internal.h"
+
 #define MHI_PCI_DEFAULT_BAR_NUM 0
 
 #define MHI_POST_RESET_DELAY_MS 500
@@ -256,6 +258,7 @@ static int mhi_pci_claim(struct mhi_controller *mhi_cntrl,
 		return err;
 	}
 	mhi_cntrl->regs = pcim_iomap_table(pdev)[bar_num];
+	mhi_cntrl->bhi = mhi_cntrl->regs + readl(mhi_cntrl->regs + BHIOFF);
 
 	err = pci_set_dma_mask(pdev, dma_mask);
 	if (err) {
@@ -391,6 +394,31 @@ static void health_check(struct timer_list *t)
 	mod_timer(&mhi_pdev->health_check_timer, jiffies + HEALTH_CHECK_PERIOD);
 }
 
+static void __mhi_sw_reset(struct mhi_controller *mhi_cntrl)
+{
+	unsigned int max_wait_ready = 100;
+
+	if (MHI_IN_PBL(mhi_get_exec_env(mhi_cntrl))) {
+		/* nothing to do, ready for BHI */
+		return;
+	}
+
+	if (mhi_get_mhi_state(mhi_cntrl) >= MHI_STATE_M0) {
+		dev_warn(mhi_cntrl->cntrl_dev, "Need reset\n");
+		writel(MHICTRL_RESET_MASK, mhi_cntrl->regs + MHICTRL);
+		msleep(10);
+	}
+
+	while (mhi_get_mhi_state(mhi_cntrl) != MHI_STATE_READY) {
+		if (!max_wait_ready--) {
+			dev_warn(mhi_cntrl->cntrl_dev, "Not ready (state %u)\n",
+				 mhi_get_mhi_state(mhi_cntrl));
+			break;
+		}
+		msleep(50);
+	}
+}
+
 static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	const struct mhi_pci_dev_info *info = (struct mhi_pci_dev_info *) id->driver_data;
@@ -451,6 +479,9 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		goto err_unregister;
 	}
 
+	/* Before starting MHI, ensure device is in good initial state */
+	__mhi_sw_reset(mhi_cntrl);
+
 	err = mhi_sync_power_up(mhi_cntrl);
 	if (err) {
 		dev_err(&pdev->dev, "failed to power up MHI controller\n");
@@ -532,6 +563,8 @@ static void mhi_pci_reset_done(struct pci_dev *pdev)
 		return;
 	}
 
+	__mhi_sw_reset(mhi_cntrl);
+
 	err = mhi_sync_power_up(mhi_cntrl);
 	if (err) {
 		dev_err(&pdev->dev, "failed to power up MHI controller\n");
-- 
2.7.4

Re: [PATCH v3] mhi: pci_generic: Ensure device readiness before starting MHI

[Bhaumik Bhatt]

Hi Loic,

On 2021-02-11 11:25 AM, Loic Poulain wrote:
> The PCI device may have not been bound from cold boot and be in
> undefined state, or simply not yet ready for MHI operations. This
> change ensures that the MHI layer is reset to initial state and
> ready for MHI initialization and power up.
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> ---
>  v2: reset only if necessary
>  v3: do not wait for MHI readiness in PBL context
> 
>  drivers/bus/mhi/pci_generic.c | 33 +++++++++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
> 
> diff --git a/drivers/bus/mhi/pci_generic.c 
> b/drivers/bus/mhi/pci_generic.c
> index c20f59e..87abd7c 100644
> --- a/drivers/bus/mhi/pci_generic.c
> +++ b/drivers/bus/mhi/pci_generic.c
> @@ -17,6 +17,8 @@
>  #include <linux/timer.h>
>  #include <linux/workqueue.h>
> 
> +#include "core/internal.h"
> +
>  #define MHI_PCI_DEFAULT_BAR_NUM 0
> 
>  #define MHI_POST_RESET_DELAY_MS 500
> @@ -256,6 +258,7 @@ static int mhi_pci_claim(struct mhi_controller 
> *mhi_cntrl,
>  		return err;
>  	}
>  	mhi_cntrl->regs = pcim_iomap_table(pdev)[bar_num];
> +	mhi_cntrl->bhi = mhi_cntrl->regs + readl(mhi_cntrl->regs + BHIOFF);
> 
>  	err = pci_set_dma_mask(pdev, dma_mask);
>  	if (err) {
> @@ -391,6 +394,31 @@ static void health_check(struct timer_list *t)
>  	mod_timer(&mhi_pdev->health_check_timer, jiffies + 
> HEALTH_CHECK_PERIOD);
>  }
> 
> +static void __mhi_sw_reset(struct mhi_controller *mhi_cntrl)
> +{
> +	unsigned int max_wait_ready = 100;
> +
> +	if (MHI_IN_PBL(mhi_get_exec_env(mhi_cntrl))) {
> +		/* nothing to do, ready for BHI */
> +		return;
> +	}
> +
> +	if (mhi_get_mhi_state(mhi_cntrl) >= MHI_STATE_M0) {
> +		dev_warn(mhi_cntrl->cntrl_dev, "Need reset\n");
> +		writel(MHICTRL_RESET_MASK, mhi_cntrl->regs + MHICTRL);
> +		msleep(10);
> +	}
> +
> +	while (mhi_get_mhi_state(mhi_cntrl) != MHI_STATE_READY) {
> +		if (!max_wait_ready--) {
> +			dev_warn(mhi_cntrl->cntrl_dev, "Not ready (state %u)\n",
> +				 mhi_get_mhi_state(mhi_cntrl));
> +			break;
> +		}
> +		msleep(50);
> +	}
> +}
> +
>  static int mhi_pci_probe(struct pci_dev *pdev, const struct 
> pci_device_id *id)
>  {
>  	const struct mhi_pci_dev_info *info = (struct mhi_pci_dev_info *)
> id->driver_data;
> @@ -451,6 +479,9 @@ static int mhi_pci_probe(struct pci_dev *pdev,
> const struct pci_device_id *id)
>  		goto err_unregister;
>  	}
> 
> +	/* Before starting MHI, ensure device is in good initial state */
> +	__mhi_sw_reset(mhi_cntrl);
> +
>  	err = mhi_sync_power_up(mhi_cntrl);
>  	if (err) {
>  		dev_err(&pdev->dev, "failed to power up MHI controller\n");
> @@ -532,6 +563,8 @@ static void mhi_pci_reset_done(struct pci_dev 
> *pdev)
>  		return;
>  	}
> 
> +	__mhi_sw_reset(mhi_cntrl);
> +
>  	err = mhi_sync_power_up(mhi_cntrl);
>  	if (err) {
>  		dev_err(&pdev->dev, "failed to power up MHI controller\n");

I have a set of changes coming in where you don't need to set BHI before 
the
mhi_sync_power_up() call. I will be moving it to 
mhi_prepare_for_power_up().

I will share the changes in the next patch series so you don't have to 
set it.

Another thing I was thinking: we could expose a function to issue an MHI 
RESET
so controllers have the freedom to use it if EE makes it possible.

This way we avoid the +#include "core/internal.h" and maintain a clear 
distinction
between controller and core.

Thanks,
Bhaumik
---
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Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v3] mhi: pci_generic: Ensure device readiness before starting MHI

[Bhaumik Bhatt]

Hi Loic,

On 2021-02-11 11:25 AM, Loic Poulain wrote:
> The PCI device may have not been bound from cold boot and be in
> undefined state, or simply not yet ready for MHI operations. This
> change ensures that the MHI layer is reset to initial state and
> ready for MHI initialization and power up.
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> ---
>  v2: reset only if necessary
>  v3: do not wait for MHI readiness in PBL context
> 
>  drivers/bus/mhi/pci_generic.c | 33 +++++++++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
> 
> diff --git a/drivers/bus/mhi/pci_generic.c 
> b/drivers/bus/mhi/pci_generic.c
> index c20f59e..87abd7c 100644
> --- a/drivers/bus/mhi/pci_generic.c
> +++ b/drivers/bus/mhi/pci_generic.c
> @@ -17,6 +17,8 @@
>  #include <linux/timer.h>
>  #include <linux/workqueue.h>
> 
> +#include "core/internal.h"
> +
>  #define MHI_PCI_DEFAULT_BAR_NUM 0
> 
>  #define MHI_POST_RESET_DELAY_MS 500
> @@ -256,6 +258,7 @@ static int mhi_pci_claim(struct mhi_controller 
> *mhi_cntrl,
>  		return err;
>  	}
>  	mhi_cntrl->regs = pcim_iomap_table(pdev)[bar_num];
> +	mhi_cntrl->bhi = mhi_cntrl->regs + readl(mhi_cntrl->regs + BHIOFF);
> 
>  	err = pci_set_dma_mask(pdev, dma_mask);
>  	if (err) {
> @@ -391,6 +394,31 @@ static void health_check(struct timer_list *t)
>  	mod_timer(&mhi_pdev->health_check_timer, jiffies + 
> HEALTH_CHECK_PERIOD);
>  }
> 
> +static void __mhi_sw_reset(struct mhi_controller *mhi_cntrl)
> +{
> +	unsigned int max_wait_ready = 100;
> +
> +	if (MHI_IN_PBL(mhi_get_exec_env(mhi_cntrl))) {
> +		/* nothing to do, ready for BHI */
> +		return;
> +	}
> +
> +	if (mhi_get_mhi_state(mhi_cntrl) >= MHI_STATE_M0) {
> +		dev_warn(mhi_cntrl->cntrl_dev, "Need reset\n");
> +		writel(MHICTRL_RESET_MASK, mhi_cntrl->regs + MHICTRL);
> +		msleep(10);
> +	}
> +
> +	while (mhi_get_mhi_state(mhi_cntrl) != MHI_STATE_READY) {
> +		if (!max_wait_ready--) {
> +			dev_warn(mhi_cntrl->cntrl_dev, "Not ready (state %u)\n",
> +				 mhi_get_mhi_state(mhi_cntrl));
> +			break;
> +		}
> +		msleep(50);
> +	}
> +}
> +
>  static int mhi_pci_probe(struct pci_dev *pdev, const struct 
> pci_device_id *id)
>  {
>  	const struct mhi_pci_dev_info *info = (struct mhi_pci_dev_info *)
> id->driver_data;
> @@ -451,6 +479,9 @@ static int mhi_pci_probe(struct pci_dev *pdev,
> const struct pci_device_id *id)
>  		goto err_unregister;
>  	}
> 
> +	/* Before starting MHI, ensure device is in good initial state */
> +	__mhi_sw_reset(mhi_cntrl);
> +
>  	err = mhi_sync_power_up(mhi_cntrl);
>  	if (err) {
>  		dev_err(&pdev->dev, "failed to power up MHI controller\n");
> @@ -532,6 +563,8 @@ static void mhi_pci_reset_done(struct pci_dev 
> *pdev)
>  		return;
>  	}
> 
> +	__mhi_sw_reset(mhi_cntrl);
> +
>  	err = mhi_sync_power_up(mhi_cntrl);
>  	if (err) {
>  		dev_err(&pdev->dev, "failed to power up MHI controller\n");

Can you share logs of what you're seeing as it is not clear why you 
would need
this patch.

We have a mechanism in place that Jeff added a while back [1], to check 
if device
is in SYS_ERROR state and do the same: issue reset and later, wait for 
ready from
within mhi_sync_power_up() API.

Note that the MHI_IN_PBL() macro includes EDL and Pass Through modes as 
well and
we do expect an MHI READY state move after Pass Through.

Thanks,
Bhaumik

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/bus/mhi/core?h=v5.11-rc7&id=e18d4e9fa79bb27de6447c0c172bb1c428a52bb2
---
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora 
Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v3] mhi: pci_generic: Ensure device readiness before starting MHI

[Loic Poulain]

Hi Bhaumik,

On Fri, 12 Feb 2021 at 02:41, Bhaumik Bhatt <bbhatt@codeaurora.org> wrote:
>
> Hi Loic,
>
> On 2021-02-11 11:25 AM, Loic Poulain wrote:
> > The PCI device may have not been bound from cold boot and be in
> > undefined state, or simply not yet ready for MHI operations. This
> > change ensures that the MHI layer is reset to initial state and
> > ready for MHI initialization and power up.
> >
> > Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
[...]
> > +
> >       err = mhi_sync_power_up(mhi_cntrl);
> >       if (err) {
> >               dev_err(&pdev->dev, "failed to power up MHI controller\n");
>
> Can you share logs of what you're seeing as it is not clear why you
> would need
> this patch.
>
> We have a mechanism in place that Jeff added a while back [1], to check
> if device
> is in SYS_ERROR state and do the same: issue reset and later, wait for
> ready from
> within mhi_sync_power_up() API.
>
> Note that the MHI_IN_PBL() macro includes EDL and Pass Through modes as
> well and
> we do expect an MHI READY state move after Pass Through.

I think this is a mix of several issues, that could be fixed by latest
Jeffrey's patch and
this one: "mhi: core: Move to polling method to wait for MHI ready".

I assume it would be easier if you send this last one as standalone
fix, for review and merge.

Regards,
Loic

Re: [PATCH v3] mhi: pci_generic: Ensure device readiness before starting MHI

[Bhaumik Bhatt]

On 2021-02-14 11:30 PM, Loic Poulain wrote:
> Hi Bhaumik,
> 
> On Fri, 12 Feb 2021 at 02:41, Bhaumik Bhatt <bbhatt@codeaurora.org> 
> wrote:
>> 
>> Hi Loic,
>> 
>> On 2021-02-11 11:25 AM, Loic Poulain wrote:
>> > The PCI device may have not been bound from cold boot and be in
>> > undefined state, or simply not yet ready for MHI operations. This
>> > change ensures that the MHI layer is reset to initial state and
>> > ready for MHI initialization and power up.
>> >
>> > Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> [...]
>> > +
>> >       err = mhi_sync_power_up(mhi_cntrl);
>> >       if (err) {
>> >               dev_err(&pdev->dev, "failed to power up MHI controller\n");
>> 
>> Can you share logs of what you're seeing as it is not clear why you
>> would need
>> this patch.
>> 
>> We have a mechanism in place that Jeff added a while back [1], to 
>> check
>> if device
>> is in SYS_ERROR state and do the same: issue reset and later, wait for
>> ready from
>> within mhi_sync_power_up() API.
>> 
>> Note that the MHI_IN_PBL() macro includes EDL and Pass Through modes 
>> as
>> well and
>> we do expect an MHI READY state move after Pass Through.
> 
> I think this is a mix of several issues, that could be fixed by latest
> Jeffrey's patch and
> this one: "mhi: core: Move to polling method to wait for MHI ready".
> 
> I assume it would be easier if you send this last one as standalone
> fix, for review and merge.
> 
Will do.
> Regards,
> Loic

Thanks,
Bhaumik
---
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora 
Forum,
a Linux Foundation Collaborative Project