Re: [PATCH v4 15/20] mtd: nand: qcom: support for command descriptor formation

[Archit Taneja]

On 08/11/2017 05:09 PM, Abhishek Sahu wrote:
> 1. Add the function for command descriptor preparation which will
>     be used only by BAM DMA and it will form the DMA descriptors
>     containing command elements
> 2. DMA_PREP_CMD flag should be used for forming command DMA
>     descriptors


Reviewed-by: Archit Taneja <architt@xxxxxxxxxxxxxx>

Thanks,
Archit

> Signed-off-by: Abhishek Sahu <absahu@xxxxxxxxxxxxxx>
> ---
>   drivers/mtd/nand/qcom_nandc.c | 108 +++++++++++++++++++++++++++++++++++-------
>   1 file changed, 92 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/mtd/nand/qcom_nandc.c b/drivers/mtd/nand/qcom_nandc.c
> index d17c466..f2cb696 100644
> --- a/drivers/mtd/nand/qcom_nandc.c
> +++ b/drivers/mtd/nand/qcom_nandc.c
> @@ -194,6 +194,14 @@
>   	      ((size) << READ_LOCATION_SIZE) |			\
>   	      ((is_last) << READ_LOCATION_LAST))
>   
> +/* Returns the NAND register physical address */
> +#define nandc_reg_phys(chip, offset) ((chip)->base_phys + (offset))
> +
> +/* Returns the dma address for reg read buffer */
> +#define reg_buf_dma_addr(chip, vaddr) \
> +	((chip)->reg_read_dma + \
> +	((uint8_t *)(vaddr) - (uint8_t *)(chip)->reg_read_buf))
> +
>   /* Returns the actual register address for NAND_FLASH_DEV_* */
>   #define nandc_dev_addr(nandc, reg) ((nandc)->props->flash_dev_offset + (reg))
>   
> @@ -311,7 +319,8 @@ struct nandc_regs {
>    *				controller
>    * @dev:			parent device
>    * @base:			MMIO base
> - * @base_dma:			physical base address of controller registers
> + * @base_phys:			physical base address of controller registers
> + * @base_dma:			dma base address of controller registers
>    * @core_clk:			controller clock
>    * @aon_clk:			another controller clock
>    *
> @@ -344,6 +353,7 @@ struct qcom_nand_controller {
>   	struct device *dev;
>   
>   	void __iomem *base;
> +	phys_addr_t base_phys;
>   	dma_addr_t base_dma;
>   
>   	struct clk *core_clk;
> @@ -745,6 +755,66 @@ static int prepare_bam_async_desc(struct qcom_nand_controller *nandc,
>   }
>   
>   /*
> + * Prepares the command descriptor for BAM DMA which will be used for NAND
> + * register reads and writes. The command descriptor requires the command
> + * to be formed in command element type so this function uses the command
> + * element from bam transaction ce array and fills the same with required
> + * data. A single SGL can contain multiple command elements so
> + * NAND_BAM_NEXT_SGL will be used for starting the separate SGL
> + * after the current command element.
> + */
> +static int prep_bam_dma_desc_cmd(struct qcom_nand_controller *nandc, bool read,
> +				 int reg_off, const void *vaddr,
> +				 int size, unsigned int flags)
> +{
> +	int bam_ce_size;
> +	int i, ret;
> +	struct bam_cmd_element *bam_ce_buffer;
> +	struct bam_transaction *bam_txn = nandc->bam_txn;
> +
> +	bam_ce_buffer = &bam_txn->bam_ce[bam_txn->bam_ce_pos];
> +
> +	/* fill the command desc */
> +	for (i = 0; i < size; i++) {
> +		if (read)
> +			bam_prep_ce(&bam_ce_buffer[i],
> +				    nandc_reg_phys(nandc, reg_off + 4 * i),
> +				    BAM_READ_COMMAND,
> +				    reg_buf_dma_addr(nandc,
> +						     (__le32 *)vaddr + i));
> +		else
> +			bam_prep_ce_le32(&bam_ce_buffer[i],
> +					 nandc_reg_phys(nandc, reg_off + 4 * i),
> +					 BAM_WRITE_COMMAND,
> +					 *((__le32 *)vaddr + i));
> +	}
> +
> +	bam_txn->bam_ce_pos += size;
> +
> +	/* use the separate sgl after this command */
> +	if (flags & NAND_BAM_NEXT_SGL) {
> +		bam_ce_buffer = &bam_txn->bam_ce[bam_txn->bam_ce_start];
> +		bam_ce_size = (bam_txn->bam_ce_pos -
> +				bam_txn->bam_ce_start) *
> +				sizeof(struct bam_cmd_element);
> +		sg_set_buf(&bam_txn->cmd_sgl[bam_txn->cmd_sgl_pos],
> +			   bam_ce_buffer, bam_ce_size);
> +		bam_txn->cmd_sgl_pos++;
> +		bam_txn->bam_ce_start = bam_txn->bam_ce_pos;
> +
> +		if (flags & NAND_BAM_NWD) {
> +			ret = prepare_bam_async_desc(nandc, nandc->cmd_chan,
> +						     DMA_PREP_FENCE |
> +						     DMA_PREP_CMD);
> +			if (ret)
> +				return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +/*
>    * Prepares the data descriptor for BAM DMA which will be used for NAND
>    * data reads and writes.
>    */
> @@ -861,19 +931,22 @@ static int read_reg_dma(struct qcom_nand_controller *nandc, int first,
>   {
>   	bool flow_control = false;
>   	void *vaddr;
> -	int size;
>   
> -	if (first == NAND_READ_ID || first == NAND_FLASH_STATUS)
> -		flow_control = true;
> +	vaddr = nandc->reg_read_buf + nandc->reg_read_pos;
> +	nandc->reg_read_pos += num_regs;
>   
>   	if (first == NAND_DEV_CMD_VLD || first == NAND_DEV_CMD1)
>   		first = nandc_dev_addr(nandc, first);
>   
> -	size = num_regs * sizeof(u32);
> -	vaddr = nandc->reg_read_buf + nandc->reg_read_pos;
> -	nandc->reg_read_pos += num_regs;
> +	if (nandc->props->is_bam)
> +		return prep_bam_dma_desc_cmd(nandc, true, first, vaddr,
> +					     num_regs, flags);
>   
> -	return prep_adm_dma_desc(nandc, true, first, vaddr, size, flow_control);
> +	if (first == NAND_READ_ID || first == NAND_FLASH_STATUS)
> +		flow_control = true;
> +
> +	return prep_adm_dma_desc(nandc, true, first, vaddr,
> +				 num_regs * sizeof(u32), flow_control);
>   }
>   
>   /*
> @@ -889,13 +962,9 @@ static int write_reg_dma(struct qcom_nand_controller *nandc, int first,
>   	bool flow_control = false;
>   	struct nandc_regs *regs = nandc->regs;
>   	void *vaddr;
> -	int size;
>   
>   	vaddr = offset_to_nandc_reg(regs, first);
>   
> -	if (first == NAND_FLASH_CMD)
> -		flow_control = true;
> -
>   	if (first == NAND_ERASED_CW_DETECT_CFG) {
>   		if (flags & NAND_ERASED_CW_SET)
>   			vaddr = &regs->erased_cw_detect_cfg_set;
> @@ -912,10 +981,15 @@ static int write_reg_dma(struct qcom_nand_controller *nandc, int first,
>   	if (first == NAND_DEV_CMD_VLD_RESTORE || first == NAND_DEV_CMD_VLD)
>   		first = nandc_dev_addr(nandc, NAND_DEV_CMD_VLD);
>   
> -	size = num_regs * sizeof(u32);
> +	if (nandc->props->is_bam)
> +		return prep_bam_dma_desc_cmd(nandc, false, first, vaddr,
> +					     num_regs, flags);
> +
> +	if (first == NAND_FLASH_CMD)
> +		flow_control = true;
>   
> -	return prep_adm_dma_desc(nandc, false, first, vaddr, size,
> -				 flow_control);
> +	return prep_adm_dma_desc(nandc, false, first, vaddr,
> +				 num_regs * sizeof(u32), flow_control);
>   }
>   
>   /*
> @@ -1177,7 +1251,8 @@ static int submit_descs(struct qcom_nand_controller *nandc)
>   		}
>   
>   		if (bam_txn->cmd_sgl_pos > bam_txn->cmd_sgl_start) {
> -			r = prepare_bam_async_desc(nandc, nandc->cmd_chan, 0);
> +			r = prepare_bam_async_desc(nandc, nandc->cmd_chan,
> +						   DMA_PREP_CMD);
>   			if (r)
>   				return r;
>   		}
> @@ -2713,6 +2788,7 @@ static int qcom_nandc_probe(struct platform_device *pdev)
>   	if (IS_ERR(nandc->base))
>   		return PTR_ERR(nandc->base);
>   
> +	nandc->base_phys = res->start;
>   	nandc->base_dma = phys_to_dma(dev, (phys_addr_t)res->start);
>   
>   	nandc->core_clk = devm_clk_get(dev, "core");

--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project