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

Jeffrey Hugo
2020-01-28T19:36:18Z

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.