Re: [PATCH v4 1/5] mtd: rawnand: qcom: Implement exec_op()

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi,

quic_mdalam@quicinc.com wrote on Thu, 15 Jun 2023 13:01:39 +0530:

> Implement exec_op() so we can later get rid of the legacy interface
> implementation.
> 
> Co-developed-by: Sricharan Ramabadhran <quic_srichara@quicinc.com>
> Signed-off-by: Sricharan Ramabadhran <quic_srichara@quicinc.com>
> Signed-off-by: Md Sadre Alam <quic_mdalam@quicinc.com>
> ---
> Change in [v4]
> 
> * No change for this patch, since this is part of exec_op
>   series posting new patch.
> 
> Change in [v3]
> 
> * Removed NAND_CMD_STATUS check in pre_command and move
>   it to status exec_op.
> 
> * Removed min() , since this check not needed
> 
> * Removed all the dummy APIs of exec_ops, and added it
>   into same patch where its getting added.
> 
> * Added qcom_check_op() API to check for unsupported feature
>   by controller in check_only path.
> 
> Change in [v2]
> 
> * Missed to post Cover-letter, so posting v2 patch with cover-letter
> 
> Change in [v1]
> 
> * Added initial support for exec_ops.
> 
>  drivers/mtd/nand/raw/qcom_nandc.c | 159 ++++++++++++++++++++++++++++++
>  1 file changed, 159 insertions(+)
> 
> diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
> index 72d6168d8a1b..d9c4c9fe2fe8 100644
> --- a/drivers/mtd/nand/raw/qcom_nandc.c
> +++ b/drivers/mtd/nand/raw/qcom_nandc.c
> @@ -157,6 +157,7 @@
>  #define	OP_PAGE_PROGRAM_WITH_ECC	0x7
>  #define	OP_PROGRAM_PAGE_SPARE		0x9
>  #define	OP_BLOCK_ERASE			0xa
> +#define	OP_CHECK_STATUS			0xc
>  #define	OP_FETCH_ID			0xb
>  #define	OP_RESET_DEVICE			0xd
>  
> @@ -235,6 +236,8 @@ nandc_set_reg(chip, reg,			\
>   */
>  #define NAND_ERASED_CW_SET		BIT(4)
>  
> +#define MAX_ADDRESS_CYCLE		5
> +#define MAX_CHUNK_SIZE			SZ_8K

New line.

>  /*
>   * This data type corresponds to the BAM transaction which will be used for all
>   * NAND transfers.
> @@ -447,6 +450,29 @@ struct qcom_nand_boot_partition {
>  	u32 page_size;
>  };
>  
> +/*
> + * Qcom op for each exec_op transfer
> + *
> + * @data_instr:			data instruction pointer
> + * @data_instr_idx:		data instruction index
> + * @rdy_timeout_ms:		wait ready timeout in ms
> + * @rdy_delay_ns:		Additional delay in ns
> + * @addr1_reg:			Address1 register value
> + * @addr2_reg:			Address2 register value
> + * @cmd_reg:			CMD register value
> + * @flag:			flag for misc instruction
> + */
> +struct qcom_op {
> +	const struct nand_op_instr *data_instr;
> +	unsigned int data_instr_idx;
> +	unsigned int rdy_timeout_ms;
> +	unsigned int rdy_delay_ns;
> +	u32 addr1_reg;
> +	u32 addr2_reg;
> +	u32 cmd_reg;
> +	u8 flag;
> +};
> +
>  /*
>   * NAND chip structure
>   *
> @@ -2867,8 +2893,141 @@ static int qcom_nand_attach_chip(struct nand_chip *chip)
>  	return 0;
>  }
>  
> +static int qcom_op_cmd_mapping(struct qcom_nand_controller *nandc, u8 cmd,
> +			       struct qcom_op *q_op)
> +{
> +	int ret;
> +
> +	switch (cmd) {
> +	case NAND_CMD_RESET:
> +		ret = OP_RESET_DEVICE;
> +		break;
> +	case NAND_CMD_READID:
> +		ret = OP_FETCH_ID;
> +		break;
> +	case NAND_CMD_PARAM:
> +		if (nandc->props->qpic_v2)
> +			ret = OP_PAGE_READ_ONFI_READ;
> +		else
> +			ret = OP_PAGE_READ;
> +		break;
> +	case NAND_CMD_ERASE1:
> +	case NAND_CMD_ERASE2:
> +		ret = OP_BLOCK_ERASE;
> +		break;
> +	case NAND_CMD_STATUS:
> +		ret = OP_CHECK_STATUS;
> +		break;
> +	case NAND_CMD_PAGEPROG:
> +		ret = OP_PROGRAM_PAGE;
> +		break;
> +	default:

Again, this is not a supported case, you should handle it. And this
must be checked upon check_only conditions as well.

> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +/* NAND framework ->exec_op() hooks and related helpers */
> +static void qcom_parse_instructions(struct nand_chip *chip,
> +				    const struct nand_subop *subop,
> +					struct qcom_op *q_op)
> +{
> +	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
> +	const struct nand_op_instr *instr = NULL;
> +	unsigned int op_id;
> +	int i;
> +
> +	memset(q_op, 0, sizeof(*q_op));
> +
> +	for (op_id = 0; op_id < subop->ninstrs; op_id++) {
> +		unsigned int offset, naddrs;
> +		const u8 *addrs;
> +
> +		instr = &subop->instrs[op_id];
> +
> +		switch (instr->type) {
> +		case NAND_OP_CMD_INSTR:
> +			q_op->cmd_reg = qcom_op_cmd_mapping(nandc, instr->ctx.cmd.opcode, q_op);
> +			q_op->rdy_delay_ns = instr->delay_ns;
> +			break;
> +
> +		case NAND_OP_ADDR_INSTR:
> +			offset = nand_subop_get_addr_start_off(subop, op_id);
> +			naddrs = nand_subop_get_num_addr_cyc(subop, op_id);
> +			addrs = &instr->ctx.addr.addrs[offset];
> +			for (i = 0; i < MAX_ADDRESS_CYCLE; i++) {
> +				if (i < 4)
> +					q_op->addr1_reg |= (u32)addrs[i] << i * 8;
> +				else
> +					q_op->addr2_reg |= addrs[i];
> +			}
> +			q_op->rdy_delay_ns = instr->delay_ns;
> +			break;
> +
> +		case NAND_OP_DATA_IN_INSTR:
> +			q_op->data_instr = instr;
> +			q_op->data_instr_idx = op_id;
> +			q_op->rdy_delay_ns = instr->delay_ns;
> +			fallthrough;
> +		case NAND_OP_DATA_OUT_INSTR:
> +			q_op->rdy_delay_ns = instr->delay_ns;
> +			break;
> +
> +		case NAND_OP_WAITRDY_INSTR:
> +			q_op->rdy_timeout_ms = instr->ctx.waitrdy.timeout_ms;
> +			q_op->rdy_delay_ns = instr->delay_ns;
> +			break;
> +		}
> +	}
> +}
> +
> +static int qcom_check_op(struct nand_chip *chip,
> +			 const struct nand_operation *op)
> +{
> +	const struct nand_op_instr *instr;
> +	int op_id;
> +
> +	for (op_id = 0; op_id < op->ninstrs; op_id++) {
> +		instr = &op->instrs[op_id];
> +
> +		switch (instr->type) {
> +		case NAND_OP_CMD_INSTR:
> +			if (instr->ctx.cmd.opcode == NAND_CMD_READCACHESEQ ||
> +			    instr->ctx.cmd.opcode == NAND_CMD_READCACHEEND)
> +				return -ENOTSUPP;

Do you really need this check? These operations have specific pattern,
no? I believe you should not need this check.
> +			break;
> +		case NAND_OP_ADDR_INSTR:
> +			if (instr->ctx.addr.naddrs > MAX_ADDRESS_CYCLE)
> +				return -ENOTSUPP;

This one is not needed either, as long as you properly define the
patterns.

> +
> +			break;
> +		case NAND_OP_DATA_IN_INSTR:
> +		case NAND_OP_DATA_OUT_INSTR:
> +			if (instr->ctx.data.len > MAX_CHUNK_SIZE)

Same.
> +				return -ENOTSUPP;
> +			break;
> +		default:
> +			break;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int qcom_nand_exec_op(struct nand_chip *chip,
> +			     const struct nand_operation *op,
> +			bool check_only)
> +{
> +	if (check_only)
> +		return qcom_check_op(chip, op);
> +
> +	return 0;
> +}
> +
>  static const struct nand_controller_ops qcom_nandc_ops = {
>  	.attach_chip = qcom_nand_attach_chip,
> +	.exec_op = qcom_nand_exec_op,

I understand the idea of making the series easier to review, and I
thank you for that, but in practice the series is not bisectable. I
doubt the driver works right after patch 1.

You will likely need two patches, one to add exec_op, one to remove the
legacy implementation.

>  };
>  
>  static void qcom_nandc_unalloc(struct qcom_nand_controller *nandc)


Thanks,
Miquèl