Subject: Re: [PATCH v1 07/12] soc: mediatek: cmdq: add write_s function

From: CK Hu <[email-masked]>
Date: Fri, 22 Nov 2019 16:56:37 +0800

Hi, Dennis:

On Thu, 2019-11-21 at 17:12 +0800, Dennis YC Hsieh wrote:
> add write_s function in cmdq helper functions which
> support large dma access.
> 
> Signed-off-by: Dennis YC Hsieh <[email-masked]>
> ---
>  drivers/soc/mediatek/mtk-cmdq-helper.c   |   34 ++++++++++++++++++++++++++++++
>  include/linux/mailbox/mtk-cmdq-mailbox.h |    2 ++
>  include/linux/soc/mediatek/mtk-cmdq.h    |   13 ++++++++++++
>  3 files changed, 49 insertions(+)
> 
> diff --git a/drivers/soc/mediatek/mtk-cmdq-helper.c b/drivers/soc/mediatek/mtk-cmdq-helper.c
> index d419e99..1b074a9 100644
> --- a/drivers/soc/mediatek/mtk-cmdq-helper.c
> +++ b/drivers/soc/mediatek/mtk-cmdq-helper.c
> @@ -15,6 +15,9 @@
>  #define CMDQ_EOC_CMD		((u64)((CMDQ_CODE_EOC << CMDQ_OP_CODE_SHIFT)) \
>  				<< 32 | CMDQ_EOC_IRQ_EN)
>  #define CMDQ_REG_TYPE		1
> +#define CMDQ_ADDR_HIGH(addr)	((u32)(((addr) >> 16) & GENMASK(31, 0)))
> +#define CMDQ_ADDR_LOW_BIT	BIT(1)
> +#define CMDQ_ADDR_LOW(addr)	((u16)(addr) | CMDQ_ADDR_LOW_BIT)
>  
>  struct cmdq_instruction {
>  	union {
> @@ -224,6 +227,37 @@ int cmdq_pkt_write_mask(struct cmdq_pkt *pkt, u8 subsys,
>  }
>  EXPORT_SYMBOL(cmdq_pkt_write_mask);
>  
> +int cmdq_pkt_write_s(struct cmdq_pkt *pkt, dma_addr_t addr,
> +		     u32 value, u32 mask)
> +{
> +	struct cmdq_instruction inst = { {0} };
> +	int err;
> +	const u16 dst_reg_idx = CMDQ_SPR_TEMP;
> +
> +	err = cmdq_pkt_assign(pkt, dst_reg_idx, CMDQ_ADDR_HIGH(addr));
> +	if (err < 0)
> +		return err;
> +
> +	if (mask != U32_MAX) {
> +		inst.op = CMDQ_CODE_MASK;
> +		inst.mask = ~mask;
> +		err = cmdq_pkt_append_command(pkt, inst);
> +		if (err < 0)
> +			return err;
> +
> +		inst.op = CMDQ_CODE_WRITE_S_MASK;
> +	} else {
> +		inst.op = CMDQ_CODE_WRITE_S;
> +	}
> +
> +	inst.sop = dst_reg_idx;
> +	inst.offset = CMDQ_ADDR_LOW(addr);
> +	inst.value = value;
> +
> +	return cmdq_pkt_append_command(pkt, inst);
> +}
> +EXPORT_SYMBOL(cmdq_pkt_write_s);
> +
>  int cmdq_pkt_wfe(struct cmdq_pkt *pkt, u16 event)
>  {
>  	struct cmdq_instruction inst = { {0} };
> diff --git a/include/linux/mailbox/mtk-cmdq-mailbox.h b/include/linux/mailbox/mtk-cmdq-mailbox.h
> index 121c3bb..8ef87e1 100644
> --- a/include/linux/mailbox/mtk-cmdq-mailbox.h
> +++ b/include/linux/mailbox/mtk-cmdq-mailbox.h
> @@ -59,6 +59,8 @@ enum cmdq_code {
>  	CMDQ_CODE_JUMP = 0x10,
>  	CMDQ_CODE_WFE = 0x20,
>  	CMDQ_CODE_EOC = 0x40,
> +	CMDQ_CODE_WRITE_S = 0x90,
> +	CMDQ_CODE_WRITE_S_MASK = 0x91,
>  	CMDQ_CODE_LOGIC = 0xa0,
>  };
>  
> diff --git a/include/linux/soc/mediatek/mtk-cmdq.h b/include/linux/soc/mediatek/mtk-cmdq.h
> index 8334021..8dbd046 100644
> --- a/include/linux/soc/mediatek/mtk-cmdq.h
> +++ b/include/linux/soc/mediatek/mtk-cmdq.h
> @@ -12,6 +12,7 @@
>  #include <linux/timer.h>
>  
>  #define CMDQ_NO_TIMEOUT		0xffffffffu
> +#define CMDQ_SPR_TEMP		0
>  
>  struct cmdq_pkt;
>  
> @@ -103,6 +104,18 @@ int cmdq_pkt_write_mask(struct cmdq_pkt *pkt, u8 subsys,
>  			u16 offset, u32 value, u32 mask);
>  
>  /**
> + * cmdq_pkt_write_s() - append write_s command with mask to the CMDQ packet
> + * @pkt:	the CMDQ packet
> + * @addr:	the physical address of register or dma
> + * @value:	the specified target value
> + * @mask:	the specified target mask
> + *
> + * Return: 0 for success; else the error code is returned
> + */
> +int cmdq_pkt_write_s(struct cmdq_pkt *pkt, dma_addr_t addr,
> +		     u32 value, u32 mask);

You have an API cmdq_pkt_read_s() which read data into gce internal
register, so I expect that cmdq_pkt_write_s() is an API which write data
from gce internal register, the expected prototype is

int cmdq_pkt_write_s(struct cmdq_pkt *pkt, phys_addr_t addr, u16
reg_idx);

Your version would confuse the user because you hide the internal
register parameter. If you want to provide this service, I would like
you to change the function name so that user would not be confused and
easily to understand what you want to do in this function.

Another choice is: cmdq_pkt_write_s() is implemented in my definition,
and user could call cmdq_pkt_assign() and cmdq_pkt_write_s() to achieve
this function.

Regards,
CK

> +
> +/**
>   * cmdq_pkt_wfe() - append wait for event command to the CMDQ packet
>   * @pkt:	the CMDQ packet
>   * @event:	the desired event type to "wait and CLEAR"

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