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Date:   Wed, 18 Oct 2023 18:38:43 +0530
From:   Manivannan Sadhasivam <mani@kernel.org>
To:     Qiang Yu <quic_qianyu@quicinc.com>
Cc:     Manivannan Sadhasivam <mani@kernel.org>, quic_jhugo@quicinc.com,
        mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org, quic_cang@quicinc.com,
        quic_mrana@quicinc.com
Subject: Re: [PATCH] bus: mhi: host: pci_generic: Add SDX75 based modem
 support
Message-ID: <20231018130843.GB47321@thinkpad>
References: <1691460215-45383-1-git-send-email-quic_qianyu@quicinc.com>
 <20230808075103.GD4990@thinkpad>
 <be205d43-b558-47eb-0250-b7415474b6e9@quicinc.com>
 <20230808105928.GF4990@thinkpad>
 <e3a206e7-f36b-d896-20f7-4e35b9743c1d@quicinc.com>
 <20231017075035.GB5274@thinkpad>
 <b7a35d1e-85e2-4c60-a049-e6234d6431df@quicinc.com>
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On Wed, Oct 18, 2023 at 09:52:55AM +0800, Qiang Yu wrote:
> 
> On 10/17/2023 3:50 PM, Manivannan Sadhasivam wrote:
> > On Wed, Aug 09, 2023 at 11:42:39AM +0800, Qiang Yu wrote:
> > > On 8/8/2023 6:59 PM, Manivannan Sadhasivam wrote:
> > > > On Tue, Aug 08, 2023 at 04:53:32PM +0800, Qiang Yu wrote:
> > > > > On 8/8/2023 3:51 PM, Manivannan Sadhasivam wrote:
> > > > > > On Tue, Aug 08, 2023 at 10:03:35AM +0800, Qiang Yu wrote:
> > > > > > > Add generic info for SDX75 based modems. SDX75 takes longer than expected
> > > > > > > (default, 8 seconds) to set ready after reboot. Hence add optional ready
> > > > > > > timeout parameter to wait enough for device ready as part of power up
> > > > > > > sequence.
> > > > > > > 
> > > > > > > Signed-off-by: Qiang Yu <quic_qianyu@quicinc.com>
> > > > > > > ---
> > > > > > >     drivers/bus/mhi/host/init.c        |  1 +
> > > > > > >     drivers/bus/mhi/host/main.c        |  7 ++++++-
> > > > > > >     drivers/bus/mhi/host/pci_generic.c | 22 ++++++++++++++++++++++
> > > > > > >     drivers/bus/mhi/host/pm.c          |  6 +++++-
> > > > > > >     include/linux/mhi.h                |  4 ++++
> > > > > > >     5 files changed, 38 insertions(+), 2 deletions(-)
> > > > > > > 
> > > > > > > diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c
> > > > > > > index f78aefd..65ceac1 100644
> > > > > > > --- a/drivers/bus/mhi/host/init.c
> > > > > > > +++ b/drivers/bus/mhi/host/init.c
> > > > > > > @@ -881,6 +881,7 @@ static int parse_config(struct mhi_controller *mhi_cntrl,
> > > > > > >     	if (!mhi_cntrl->timeout_ms)
> > > > > > >     		mhi_cntrl->timeout_ms = MHI_TIMEOUT_MS;
> > > > > > > +	mhi_cntrl->ready_timeout_ms = config->ready_timeout_ms;
> > > > > > >     	mhi_cntrl->bounce_buf = config->use_bounce_buf;
> > > > > > >     	mhi_cntrl->buffer_len = config->buf_len;
> > > > > > >     	if (!mhi_cntrl->buffer_len)
> > > > > > > diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
> > > > > > > index 74a7543..8590926 100644
> > > > > > > --- a/drivers/bus/mhi/host/main.c
> > > > > > > +++ b/drivers/bus/mhi/host/main.c
> > > > > > > @@ -43,8 +43,13 @@ int __must_check mhi_poll_reg_field(struct mhi_controller *mhi_cntrl,
> > > > > > >     				    u32 mask, u32 val, u32 delayus)
> > > > > > >     {
> > > > > > >     	int ret;
> > > > > > > -	u32 out, retry = (mhi_cntrl->timeout_ms * 1000) / delayus;
> > > > > > > +	u32 out, retry;
> > > > > > > +	u32 timeout_ms = mhi_cntrl->timeout_ms;
> > > > > > > +	if (mhi_cntrl->ready_timeout_ms && mask == MHISTATUS_READY_MASK)
> > > > > > > +		timeout_ms = mhi_cntrl->ready_timeout_ms;
> > > > > > Instead of handling the timeout inside mhi_poll_reg_field(), you should pass the
> > > > > > appropriate timeout value to this function.
> > > > > OK, will do.
> > > > > > > +
> > > > > > > +	retry = (timeout_ms * 1000) / delayus;
> > > > > > >     	while (retry--) {
> > > > > > >     		ret = mhi_read_reg_field(mhi_cntrl, base, offset, mask, &out);
> > > > > > >     		if (ret)
> > > > > > > diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c
> > > > > > > index fcd80bc..9c601f0 100644
> > > > > > > --- a/drivers/bus/mhi/host/pci_generic.c
> > > > > > > +++ b/drivers/bus/mhi/host/pci_generic.c
> > > > > > > @@ -269,6 +269,16 @@ static struct mhi_event_config modem_qcom_v1_mhi_events[] = {
> > > > > > >     	MHI_EVENT_CONFIG_HW_DATA(5, 2048, 101)
> > > > > > >     };
> > > > > > > +static const struct mhi_controller_config modem_qcom_v2_mhiv_config = {
> > > > > > > +	.max_channels = 128,
> > > > > > > +	.timeout_ms = 8000,
> > > > > > > +	.ready_timeout_ms = 50000,
> > > > > > > +	.num_channels = ARRAY_SIZE(modem_qcom_v1_mhi_channels),
> > > > > > > +	.ch_cfg = modem_qcom_v1_mhi_channels,
> > > > > > > +	.num_events = ARRAY_SIZE(modem_qcom_v1_mhi_events),
> > > > > > > +	.event_cfg = modem_qcom_v1_mhi_events,
> > > > > > > +};
> > > > > > > +
> > > > > > >     static const struct mhi_controller_config modem_qcom_v1_mhiv_config = {
> > > > > > >     	.max_channels = 128,
> > > > > > >     	.timeout_ms = 8000,
> > > > > > > @@ -278,6 +288,16 @@ static const struct mhi_controller_config modem_qcom_v1_mhiv_config = {
> > > > > > >     	.event_cfg = modem_qcom_v1_mhi_events,
> > > > > > >     };
> > > > > > > +static const struct mhi_pci_dev_info mhi_qcom_sdx75_info = {
> > > > > > > +	.name = "qcom-sdx75m",
> > > > > > > +	.fw = "qcom/sdx75m/xbl.elf",
> > > > > > > +	.edl = "qcom/sdx75m/edl.mbn",
> > > > > > > +	.config = &modem_qcom_v2_mhiv_config,
> > > > > > > +	.bar_num = MHI_PCI_DEFAULT_BAR_NUM,
> > > > > > > +	.dma_data_width = 32,
> > > > > > > +	.sideband_wake = false,
> > > > > > > +};
> > > > > > > +
> > > > > > >     static const struct mhi_pci_dev_info mhi_qcom_sdx65_info = {
> > > > > > >     	.name = "qcom-sdx65m",
> > > > > > >     	.fw = "qcom/sdx65m/xbl.elf",
> > > > > > > @@ -597,6 +617,8 @@ static const struct pci_device_id mhi_pci_id_table[] = {
> > > > > > >     		.driver_data = (kernel_ulong_t) &mhi_telit_fn990_info },
> > > > > > >     	{ PCI_DEVICE(PCI_VENDOR_ID_QCOM, 0x0308),
> > > > > > >     		.driver_data = (kernel_ulong_t) &mhi_qcom_sdx65_info },
> > > > > > > +	{ PCI_DEVICE(PCI_VENDOR_ID_QCOM, 0x0309),
> > > > > > > +		.driver_data = (kernel_ulong_t) &mhi_qcom_sdx75_info },
> > > > > > >     	{ PCI_DEVICE(PCI_VENDOR_ID_QUECTEL, 0x1001), /* EM120R-GL (sdx24) */
> > > > > > >     		.driver_data = (kernel_ulong_t) &mhi_quectel_em1xx_info },
> > > > > > >     	{ PCI_DEVICE(PCI_VENDOR_ID_QUECTEL, 0x1002), /* EM160R-GL (sdx24) */
> > > > > > > diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c
> > > > > > > index 8a4362d..6f049e0 100644
> > > > > > > --- a/drivers/bus/mhi/host/pm.c
> > > > > > > +++ b/drivers/bus/mhi/host/pm.c
> > > > > > > @@ -1202,14 +1202,18 @@ EXPORT_SYMBOL_GPL(mhi_power_down);
> > > > > > >     int mhi_sync_power_up(struct mhi_controller *mhi_cntrl)
> > > > > > >     {
> > > > > > >     	int ret = mhi_async_power_up(mhi_cntrl);
> > > > > > > +	u32 timeout_ms;
> > > > > > >     	if (ret)
> > > > > > >     		return ret;
> > > > > > > +	/* Some devices need more time to set ready during power up */
> > > > > > > +	timeout_ms = mhi_cntrl->ready_timeout_ms ?
> > > > > > > +		mhi_cntrl->ready_timeout_ms : mhi_cntrl->timeout_ms;
> > > > > > Since you are using this extended timeout value in a couple of places (not just
> > > > > > for checking READY_STATE), it is better to use the existing "timeout_ms"
> > > > > > parameter.
> > > > > > 
> > > > > > - Mani
> > > > > We use ready_timeout_ms here is because READY_STATE is polled in a
> > > > > workqueue,  in parallel with waiting valid EE.
> > > > > 
> > > > > That means we start to wait valid EE and poll ready like at same time
> > > > > instead of starting to wait EE after ready state.
> > > > > 
> > > > > Thus the total time it takes to wait valid EE is about the time for polling
> > > > > ready.
> > > > > 
> > > > Yes, but why can't you still increase "timeout_ms" for SDX75 and use the same?
> > > > 
> > > > Btw, please do not send another version while the discussion is going on for the
> > > > current one.
> > > > 
> > > > - Mani
> > > SDX75 only needs 50 seconds when setting ready for the first time after
> > > power on. Other state transitions
> > > 
> > > is expected to wait only 8 seconds. If we use 50s for every state
> > > transition, it's OK but not friendly in some cases.
> > > 
> > > 
> > > For example, host is resuming from suspend, but device has already crashed
> > > and tansferred to Sahara mode when
> > > 
> > > in suspended state. Thus host must wait M0 event timeout, and then reinit
> > > mhi and tranfer to SBL state in recovery
> > > 
> > > process. If we set mhi_cntrl->timeout_ms=50s, we have to wait 50s to collect
> > > crash dump after seeing resume fail log.
> > > 
> > Hmm. Can't you fix the firmware? Taking 50s to bootup doesn't look good from
> > user perspective.
> > 
> > - Mani
>  It is a firmware limitation and we can't fix it now.

Okay. Then I'm fine with this workaround.

Please post the next version incorporating other comments.

- Mani

> > > > > > >     	wait_event_timeout(mhi_cntrl->state_event,
> > > > > > >     			   MHI_IN_MISSION_MODE(mhi_cntrl->ee) ||
> > > > > > >     			   MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state),
> > > > > > > -			   msecs_to_jiffies(mhi_cntrl->timeout_ms));
> > > > > > > +			   msecs_to_jiffies(timeout_ms));
> > > > > > >     	ret = (MHI_IN_MISSION_MODE(mhi_cntrl->ee)) ? 0 : -ETIMEDOUT;
> > > > > > >     	if (ret)
> > > > > > > diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> > > > > > > index f6de4b6..a43e5f8 100644
> > > > > > > --- a/include/linux/mhi.h
> > > > > > > +++ b/include/linux/mhi.h
> > > > > > > @@ -266,6 +266,7 @@ struct mhi_event_config {
> > > > > > >      * struct mhi_controller_config - Root MHI controller configuration
> > > > > > >      * @max_channels: Maximum number of channels supported
> > > > > > >      * @timeout_ms: Timeout value for operations. 0 means use default
> > > > > > > + * @ready_timeout_ms: Timeout value for waiting device to be ready (optional)
> > > > > > >      * @buf_len: Size of automatically allocated buffers. 0 means use default
> > > > > > >      * @num_channels: Number of channels defined in @ch_cfg
> > > > > > >      * @ch_cfg: Array of defined channels
> > > > > > > @@ -277,6 +278,7 @@ struct mhi_event_config {
> > > > > > >     struct mhi_controller_config {
> > > > > > >     	u32 max_channels;
> > > > > > >     	u32 timeout_ms;
> > > > > > > +	u32 ready_timeout_ms;
> > > > > > >     	u32 buf_len;
> > > > > > >     	u32 num_channels;
> > > > > > >     	const struct mhi_channel_config *ch_cfg;
> > > > > > > @@ -326,6 +328,7 @@ struct mhi_controller_config {
> > > > > > >      * @pm_mutex: Mutex for suspend/resume operation
> > > > > > >      * @pm_lock: Lock for protecting MHI power management state
> > > > > > >      * @timeout_ms: Timeout in ms for state transitions
> > > > > > > + * @ready_timeout_ms: Timeout in ms for waiting device to be ready (optional)
> > > > > > >      * @pm_state: MHI power management state
> > > > > > >      * @db_access: DB access states
> > > > > > >      * @ee: MHI device execution environment
> > > > > > > @@ -413,6 +416,7 @@ struct mhi_controller {
> > > > > > >     	struct mutex pm_mutex;
> > > > > > >     	rwlock_t pm_lock;
> > > > > > >     	u32 timeout_ms;
> > > > > > > +	u32 ready_timeout_ms;
> > > > > > >     	u32 pm_state;
> > > > > > >     	u32 db_access;
> > > > > > >     	enum mhi_ee_type ee;
> > > > > > > -- 
> > > > > > > 2.7.4
> > > > > > > 

-- 
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