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Date:   Fri, 26 Feb 2021 20:22:45 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To:     Gokul Sriram Palanisamy <gokulsri@codeaurora.org>
Cc:     linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        jhugo@codeaurora.org, hemantk@codeaurora.org,
        sricharan@codeaurora.org
Subject: Re: [PATCH v2] bus: mhi: core: Add unique qrtr node id support
Message-ID: <20210226145245.GB70936@thinkpad>
References: <1614336169-31467-1-git-send-email-gokulsri@codeaurora.org>
 <1614336169-31467-2-git-send-email-gokulsri@codeaurora.org>
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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?

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
>