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Date:   Mon, 01 Mar 2021 10:17:10 -0800
From:   Bhaumik Bhatt <bbhatt@codeaurora.org>
To:     Kalle Valo <kvalo@codeaurora.org>
Cc:     Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
        Gokul Sriram Palanisamy <gokulsri@codeaurora.org>,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        jhugo@codeaurora.org, hemantk@codeaurora.org,
        sricharan@codeaurora.org, ath11k@lists.infradead.org,
        kvalo=codeaurora.org@codeaurora.org
Subject: Re: [PATCH v2] bus: mhi: core: Add unique qrtr node id support
Organization: Qualcomm Innovation Center, Inc.
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On 2021-03-01 03:14 AM, Kalle Valo wrote:
> + ath11k list
> 
> Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> writes:
> 
>> 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@OpenWrt:/# 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@codeaurora.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?
> 
> I'm not sure what QCN9000 means but I'm guessing it's QCN9074. We have
> initial QCN9074 support in ath11k but there are some issues still so
> it's not enabled by default (yet):
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git/commit/?h=ath-next&id=4e80946197a83a6115e308334618449b77696d6a
> 
> And I suspect we have this same qrtr issue with any ath11k PCI device,
> including QCA6390, so this is not a QCN9074 specific problem.
> 
> BTW Gokul, please always CC the ath11k list when submitting patches
> which are related to ath11k.

QRTR sits on top of MHI so shouldn't this be handled outside of MHI 
after
MHI is operational? We cannot allow PCI code in MHI core driver but this
can be handled pre or post MHI power-up in whatever way you desire that 
does
not have to directly involve MHI.

Thanks,
Bhaumik
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