Unverified Commit e7edd2cf authored by Chuanhong Guo's avatar Chuanhong Guo Committed by Mark Brown
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spi: spi-mtk-nor: make use of full capability of prg mode 



"program" mode on this controller can trigger up to 56 bits of data
shifting. During the operation, data in PRGDATA[0-5] will be
shifted out from MOSI, and data from MISO will be continuously filling
SHREG[0-9].
Currently this mode is used to implement transfer_one_message for 6-byte
full-duplex transfer, but it can execute a transfer for up-to 7 bytes
as long as the last byte is read only.
transfer_one_message is expected to perform full-duplex transfer,
instead of transfer with specific format. mtk_nor_spi_mem_prg is
added here to use this extra byte.

Newer version of this controller can trigger longer data shifting with
shift bytes more than PRGDATA_MAX + SHREG_MAX. This patch is implemented
with that in mind and it checks against both SHREG_MAX and PRG_CNT_MAX
for future support of new controllers.

Signed-off-by: default avatarChuanhong Guo <gch981213@gmail.com>
Link: https://lore.kernel.org/r/20200924152730.733243-2-gch981213@gmail.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 9d362152

drivers/spi/spi-mtk-nor.c

+80 −2
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#define MTK_NOR_CMD_MASK		GENMASK(5, 0)



#define MTK_NOR_REG_PRG_CNT		0x04

#define MTK_NOR_PRG_CNT_MAX		56

#define MTK_NOR_REG_RDATA		0x0c



#define MTK_NOR_REG_RADR0		0x10
@@ -404,6 +405,83 @@ static int mtk_nor_pp_unbuffered(struct mtk_nor *sp, 
	return mtk_nor_cmd_exec(sp, MTK_NOR_CMD_WRITE, 6 * BITS_PER_BYTE);

}



static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)

{

	int rx_len = 0;

	int reg_offset = MTK_NOR_REG_PRGDATA_MAX;

	int tx_len, prg_len;

	int i, ret;

	void __iomem *reg;

	u8 bufbyte;



	tx_len = op->cmd.nbytes + op->addr.nbytes;



	// count dummy bytes only if we need to write data after it

	if (op->data.dir == SPI_MEM_DATA_OUT)

		tx_len += op->dummy.nbytes + op->data.nbytes;

	else if (op->data.dir == SPI_MEM_DATA_IN)

		rx_len = op->data.nbytes;



	prg_len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes +

		  op->data.nbytes;



	// an invalid op may reach here if the caller calls exec_op without

	// adjust_op_size. return -EINVAL instead of -ENOTSUPP so that

	// spi-mem won't try this op again with generic spi transfers.

	if ((tx_len > MTK_NOR_REG_PRGDATA_MAX + 1) ||

	    (rx_len > MTK_NOR_REG_SHIFT_MAX + 1) ||

	    (prg_len > MTK_NOR_PRG_CNT_MAX / 8))

		return -EINVAL;



	// fill tx data

	for (i = op->cmd.nbytes; i > 0; i--, reg_offset--) {

		reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);

		bufbyte = (op->cmd.opcode >> ((i - 1) * BITS_PER_BYTE)) & 0xff;

		writeb(bufbyte, reg);

	}



	for (i = op->addr.nbytes; i > 0; i--, reg_offset--) {

		reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);

		bufbyte = (op->addr.val >> ((i - 1) * BITS_PER_BYTE)) & 0xff;

		writeb(bufbyte, reg);

	}



	if (op->data.dir == SPI_MEM_DATA_OUT) {

		for (i = 0; i < op->dummy.nbytes; i++, reg_offset--) {

			reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);

			writeb(0, reg);

		}



		for (i = 0; i < op->data.nbytes; i++, reg_offset--) {

			reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);

			writeb(((const u8 *)(op->data.buf.out))[i], reg);

		}

	}



	for (; reg_offset >= 0; reg_offset--) {

		reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);

		writeb(0, reg);

	}



	// trigger op

	writel(prg_len * BITS_PER_BYTE, sp->base + MTK_NOR_REG_PRG_CNT);

	ret = mtk_nor_cmd_exec(sp, MTK_NOR_CMD_PROGRAM,

			       prg_len * BITS_PER_BYTE);

	if (ret)

		return ret;



	// fetch read data

	reg_offset = 0;

	if (op->data.dir == SPI_MEM_DATA_IN) {

		for (i = op->data.nbytes - 1; i >= 0; i--, reg_offset++) {

			reg = sp->base + MTK_NOR_REG_SHIFT(reg_offset);

			((u8 *)(op->data.buf.in))[i] = readb(reg);

		}

	}



	return 0;

}



static int mtk_nor_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)

{

	struct mtk_nor *sp = spi_controller_get_devdata(mem->spi->master);
@@ -411,7 +489,7 @@ static int mtk_nor_exec_op(struct spi_mem *mem, const struct spi_mem_op *op) 


	if ((op->data.nbytes == 0) ||

	    ((op->addr.nbytes != 3) && (op->addr.nbytes != 4)))

		return -ENOTSUPP;

		return mtk_nor_spi_mem_prg(sp, op);



	if (op->data.dir == SPI_MEM_DATA_OUT) {

		mtk_nor_set_addr(sp, op);
@@ -441,7 +519,7 @@ static int mtk_nor_exec_op(struct spi_mem *mem, const struct spi_mem_op *op) 
		}

	}



	return -ENOTSUPP;

	return mtk_nor_spi_mem_prg(sp, op);

}



static int mtk_nor_setup(struct spi_device *spi)

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