Re: [PATCH 08/16] bus: mhi: core: Add support for downloading firmware over BHIe

From: Jeffrey Hugo <jhugo@codeaurora.org>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
	gregkh@linuxfoundation.org, arnd@arndb.de
Cc: smohanad@codeaurora.org, kvalo@codeaurora.org,
	bjorn.andersson@linaro.org, hemantk@codeaurora.org,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 08/16] bus: mhi: core: Add support for downloading firmware over BHIe
Date: Tue, 28 Jan 2020 12:36:04 -0700	[thread overview]
Message-ID: <00e3d4f8-89ab-79f0-7094-90cc6d85fa41@codeaurora.org> (raw)
In-Reply-To: <20200123111836.7414-9-manivannan.sadhasivam@linaro.org>

On 1/23/2020 4:18 AM, Manivannan Sadhasivam wrote:
> MHI supports downloading the device firmware over BHI/BHIe (Boot Host
> Interface) protocol. Hence, this commit adds necessary helpers, which
> will be called during device power up stage.
> 
> This is based on the patch submitted by Sujeev Dias:
> https://lkml.org/lkml/2018/7/9/989
> 
> Signed-off-by: Sujeev Dias <sdias@codeaurora.org>
> Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
> [mani: splitted the data transfer patch and cleaned up for upstream]
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
>   drivers/bus/mhi/core/boot.c     | 268 ++++++++++++++++++++++++++++++++
>   drivers/bus/mhi/core/init.c     |   1 +
>   drivers/bus/mhi/core/internal.h |   1 +
>   3 files changed, 270 insertions(+)
> 
> diff --git a/drivers/bus/mhi/core/boot.c b/drivers/bus/mhi/core/boot.c
> index 0996f18c4281..36956fb6eff2 100644
> --- a/drivers/bus/mhi/core/boot.c
> +++ b/drivers/bus/mhi/core/boot.c
> @@ -20,6 +20,121 @@
>   #include <linux/wait.h>
>   #include "internal.h"
>   
> +/* Download AMSS image to device */

Nit: I don't feel like this comment really adds any value.  I feel like 
it either should have more content, or be removed.  What do you think?
> +static int mhi_fw_load_amss(struct mhi_controller *mhi_cntrl,
> +			    const struct mhi_buf *mhi_buf)
> +{

> +/* Download SBL image to device */

Same here.  Comment seems self evident from the function name.
> +static int mhi_fw_load_sbl(struct mhi_controller *mhi_cntrl,
> +			   dma_addr_t dma_addr,
> +			   size_t size)
> +{
> +	u32 tx_status, val, session_id;
> +	int i, ret;
> +	void __iomem *base = mhi_cntrl->bhi;
> +	rwlock_t *pm_lock = &mhi_cntrl->pm_lock;
> +	struct {
> +		char *name;
> +		u32 offset;
> +	} error_reg[] = {
> +		{ "ERROR_CODE", BHI_ERRCODE },
> +		{ "ERROR_DBG1", BHI_ERRDBG1 },
> +		{ "ERROR_DBG2", BHI_ERRDBG2 },
> +		{ "ERROR_DBG3", BHI_ERRDBG3 },
> +		{ NULL },
> +	};
> +
> +	read_lock_bh(pm_lock);
> +	if (!MHI_REG_ACCESS_VALID(mhi_cntrl->pm_state)) {
> +		read_unlock_bh(pm_lock);
> +		goto invalid_pm_state;
> +	}
> +
> +	/* Start SBL download via BHI protocol */

I'm wondering, what do you think about having a debug level message here 
that SBL is being loaded?  I think it would be handy for looking into 
the device state.

> +	mhi_write_reg(mhi_cntrl, base, BHI_STATUS, 0);
> +	mhi_write_reg(mhi_cntrl, base, BHI_IMGADDR_HIGH,
> +		      upper_32_bits(dma_addr));
> +	mhi_write_reg(mhi_cntrl, base, BHI_IMGADDR_LOW,
> +		      lower_32_bits(dma_addr));
> +	mhi_write_reg(mhi_cntrl, base, BHI_IMGSIZE, size);
> +	session_id = prandom_u32() & BHI_TXDB_SEQNUM_BMSK;
> +	mhi_write_reg(mhi_cntrl, base, BHI_IMGTXDB, session_id);
> +	read_unlock_bh(pm_lock);
> +
> +
> +static void mhi_firmware_copy(struct mhi_controller *mhi_cntrl,
> +			      const struct firmware *firmware,
> +			      struct image_info *img_info)

Perhaps its just me, but the parameters on the second and third lines do 
not look aligned in the style used in the rest of the file.

-- 
Jeffrey Hugo
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.