linux-kernel - Re: [PATCH v2] bus: mhi: core: Add unique qrtr node id support

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Message-ID: <444e646b9781e24f9e2f95f7db85fcbd@codeaurora.org>
Date:   Sat, 27 Feb 2021 13:55:12 +0530
From:   gokulsri@...eaurora.org
To:     bbhatt@...eaurora.org,
        Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
        jhugo@...eaurora.org
Cc:     linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        hemantk@...eaurora.org, sricharan@...eaurora.org,
        bjorn.andersson@...aro.org
Subject: Re: [PATCH v2] bus: mhi: core: Add unique qrtr node id support

  Hi
On 2021-02-26 23:01, Bhaumik Bhatt wrote:
> On 2021-02-26 06:52 AM, Manivannan Sadhasivam wrote:
>> On Fri, Feb 26, 2021 at 04:12:49PM +0530, Gokul Sriram Palanisamy 
>> wrote:
>>> On platforms with two or more identical mhi
>>> devices, qmi service will run with identical
>>> qrtr-node-id. Because of this identical ID,
>>> host qrtr-lookup cannot register more than one
>>> qmi service with identical node ID. Ultimately,
>>> only one qmi service will be avilable for the
>>> underlying drivers to communicate with.
>>> 
>>> On QCN9000, it implements a unique qrtr-node-id
>>> and qmi instance ID using a unique instance ID
>>> written to a debug register from host driver
>>> soon after SBL is loaded.
>>> 
>>> This change generates a unique instance ID from
>>> PCIe domain number and bus number, writes to the
>>> given debug register just after SBL is loaded so
>>> that it is available for FW when the QMI service
>>> is spawned.
>>> 
>>> sample:
>>> root@...nWrt:/# qrtr-lookup
>>>   Service Version Instance Node  Port
>>>        15       1        0    8     1 Test service
>>>        69       1        8    8     2 ATH10k WLAN firmware service
>>>        15       1        0   24     1 Test service
>>>        69       1       24   24     2 ATH10k WLAN firmware service
>>> 
>>> Here 8 and 24 on column 3 (QMI Instance ID)
>>> and 4 (QRTR Node ID) are the node IDs that
>>> is unique per mhi device.
>>> 
>>> Signed-off-by: Gokul Sriram Palanisamy <gokulsri@...eaurora.org>
>>> ---
>>>  drivers/bus/mhi/core/boot.c | 14 ++++++++++++++
>>>  1 file changed, 14 insertions(+)
>>> 
>>> diff --git a/drivers/bus/mhi/core/boot.c 
>>> b/drivers/bus/mhi/core/boot.c
>>> index c2546bf..5e5dad5 100644
>>> --- a/drivers/bus/mhi/core/boot.c
>>> +++ b/drivers/bus/mhi/core/boot.c
>>> @@ -16,8 +16,12 @@
>>>  #include <linux/random.h>
>>>  #include <linux/slab.h>
>>>  #include <linux/wait.h>
>>> +#include <linux/pci.h>
>>>  #include "internal.h"
>>> 
>>> +#define QRTR_INSTANCE_MASK	0x000000FF
>>> +#define QRTR_INSTANCE_SHIFT	0
>>> +
>>>  /* Setup RDDM vector table for RDDM transfer and program RXVEC */
>>>  void mhi_rddm_prepare(struct mhi_controller *mhi_cntrl,
>>>  		      struct image_info *img_info)
>>> @@ -391,6 +395,9 @@ void mhi_fw_load_handler(struct mhi_controller 
>>> *mhi_cntrl)
>>>  	const struct firmware *firmware = NULL;
>>>  	struct image_info *image_info;
>>>  	struct device *dev = &mhi_cntrl->mhi_dev->dev;
>>> +	struct pci_dev *pci_dev = to_pci_dev(mhi_cntrl->cntrl_dev);
>>> +	struct pci_bus *bus = pci_dev->bus;
>>> +	uint32_t instance;
>>>  	const char *fw_name;
>>>  	void *buf;
>>>  	dma_addr_t dma_addr;
>>> @@ -466,6 +473,13 @@ void mhi_fw_load_handler(struct mhi_controller 
>>> *mhi_cntrl)
>>>  		return;
>>>  	}
>>> 
>>> +	instance = ((pci_domain_nr(bus) & 0xF) << 4) | (bus->number & 0xF);
>>> +	instance &= QRTR_INSTANCE_MASK;
>>> +
>>> +	mhi_write_reg_field(mhi_cntrl, mhi_cntrl->bhi,
>>> +			    BHI_ERRDBG2, QRTR_INSTANCE_MASK,
>>> +			    QRTR_INSTANCE_SHIFT, instance);
>> 
>> You cannot not do this in MHI stack. Why can't you do this in the MHI 
>> controller
>> specific to QCN9000? And btw, is QCN9000 supported in mainline?
>> 
>> Thanks,
>> Mani
>> 
>>> +
>>>  	write_lock_irq(&mhi_cntrl->pm_lock);
>>>  	mhi_cntrl->dev_state = MHI_STATE_RESET;
>>>  	write_unlock_irq(&mhi_cntrl->pm_lock);
>>> --
>>> 2.7.4
>>> 
> 
> As others have stated, please refrain from adding protocol specific
> code (such as PCIe)
> in the MHI core driver. Please have this change in your controller.
> 
> If there is access to BHI registers required prior to power up from
> MHI core, it is not
> exposed right now. We can talk about how you can  achieve that, so you
> can do this write
> in your controller after mhi_prepare_for_power_up().
> 
> Thanks,
> Bhaumik
> ---
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora 
> Forum,
> a Linux Foundation Collaborative Project
  Thank you Jeffrey, Manivannan and Bhaumik.
  Adding Bjorn for his review and suggestions.

  Thanks,
  Gokul