[PATCH v4] mtd: devices: m25p80: Use the spi-mem dirmap API

[Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>]

From: Boris Brezillon <boris.brezillon@bootlin.com>

Make use of the spi-mem direct mapping API to let advanced controllers
optimize read/write operations when they support direct mapping.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Tested-by: Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com>

---
This is a leftover unmerged patch of the "spi: spi-mem: Add a direct mapping
API" series, atop of the 'mtd/next' branch of the MTD 'linux.git' repo.

Changes in v4:
- Add Yogesh's T-b and my S-o-b

Changes in v3:
- Make nor->read/write() functional before the direct mappings have been
  created
- Add Miquel's R-b

Changes in v2:
- Rename the dirmap fields
- Return directly after calling dirmap_read/write() and let the spi-nor
  framework call us again if those functions returned less than the
  requested length

 drivers/mtd/devices/m25p80.c |  102 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 99 insertions(+), 3 deletions(-)

Index: linux/drivers/mtd/devices/m25p80.c
===================================================================
--- linux.orig/drivers/mtd/devices/m25p80.c
+++ linux/drivers/mtd/devices/m25p80.c
@@ -31,8 +31,70 @@
 struct m25p {
 	struct spi_mem		*spimem;
 	struct spi_nor		spi_nor;
+	struct {
+		struct spi_mem_dirmap_desc *rdesc;
+		struct spi_mem_dirmap_desc *wdesc;
+	} dirmap;
 };
 
+static int m25p_create_write_dirmap(struct m25p *flash)
+{
+	struct spi_nor *nor = &flash->spi_nor;
+	struct spi_mem_dirmap_info info = {
+		.op_tmpl = SPI_MEM_OP(SPI_MEM_OP_CMD(nor->program_opcode, 1),
+				      SPI_MEM_OP_ADDR(nor->addr_width, 0, 1),
+				      SPI_MEM_OP_NO_DUMMY,
+				      SPI_MEM_OP_DATA_OUT(0, NULL, 1)),
+		.offset = 0,
+		.length = flash->spi_nor.mtd.size,
+	};
+	struct spi_mem_op *op = &info.op_tmpl;
+
+	/* get transfer protocols. */
+	op->cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->write_proto);
+	op->addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->write_proto);
+	op->dummy.buswidth = op->addr.buswidth;
+	op->data.buswidth = spi_nor_get_protocol_data_nbits(nor->write_proto);
+
+	if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)
+		op->addr.nbytes = 0;
+
+	flash->dirmap.wdesc = spi_mem_dirmap_create(flash->spimem, &info);
+	if (IS_ERR(flash->dirmap.wdesc))
+		return PTR_ERR(flash->dirmap.wdesc);
+
+	return 0;
+}
+
+static int m25p_create_read_dirmap(struct m25p *flash)
+{
+	struct spi_nor *nor = &flash->spi_nor;
+	struct spi_mem_dirmap_info info = {
+		.op_tmpl = SPI_MEM_OP(SPI_MEM_OP_CMD(nor->read_opcode, 1),
+				      SPI_MEM_OP_ADDR(nor->addr_width, 0, 1),
+				      SPI_MEM_OP_DUMMY(nor->read_dummy, 1),
+				      SPI_MEM_OP_DATA_IN(0, NULL, 1)),
+		.offset = 0,
+		.length = flash->spi_nor.mtd.size,
+	};
+	struct spi_mem_op *op = &info.op_tmpl;
+
+	/* get transfer protocols. */
+	op->cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->read_proto);
+	op->addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->read_proto);
+	op->dummy.buswidth = op->addr.buswidth;
+	op->data.buswidth = spi_nor_get_protocol_data_nbits(nor->read_proto);
+
+	/* convert the dummy cycles to the number of bytes */
+	op->dummy.nbytes = (nor->read_dummy * op->dummy.buswidth) / 8;
+
+	flash->dirmap.rdesc = spi_mem_dirmap_create(flash->spimem, &info);
+	if (IS_ERR(flash->dirmap.rdesc))
+		return PTR_ERR(flash->dirmap.rdesc);
+
+	return 0;
+}
+
 static int m25p80_read_reg(struct spi_nor *nor, u8 code, u8 *val, int len)
 {
 	struct m25p *flash = nor->priv;
@@ -92,6 +154,9 @@ static ssize_t m25p80_write(struct spi_n
 				   SPI_MEM_OP_DATA_OUT(len, buf, 1));
 	int ret;
 
+	if (flash->dirmap.wdesc)
+		return spi_mem_dirmap_write(flash->dirmap.wdesc, to, len, buf);
+
 	/* get transfer protocols. */
 	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->write_proto);
 	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->write_proto);
@@ -128,6 +193,9 @@ static ssize_t m25p80_read(struct spi_no
 	size_t remaining = len;
 	int ret;
 
+	if (flash->dirmap.rdesc)
+		return spi_mem_dirmap_read(flash->dirmap.rdesc, from, len, buf);
+
 	/* get transfer protocols. */
 	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->read_proto);
 	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->read_proto);
@@ -238,19 +306,47 @@ static int m25p_probe(struct spi_mem *sp
 	if (ret)
 		return ret;
 
-	return mtd_device_register(&nor->mtd, data ? data->parts : NULL,
-				   data ? data->nr_parts : 0);
+	ret = m25p_create_write_dirmap(flash);
+	if (ret)
+		return ret;
+
+	ret = m25p_create_read_dirmap(flash);
+	if (ret)
+		goto err_destroy_write_dirmap;
+
+	ret = mtd_device_register(&nor->mtd, data ? data->parts : NULL,
+				  data ? data->nr_parts : 0);
+	if (ret)
+		goto err_destroy_read_dirmap;
+
+	return 0;
+
+err_destroy_read_dirmap:
+	spi_mem_dirmap_destroy(flash->dirmap.rdesc);
+
+err_destroy_write_dirmap:
+	spi_mem_dirmap_destroy(flash->dirmap.wdesc);
+
+	return ret;
 }
 
 
 static int m25p_remove(struct spi_mem *spimem)
 {
 	struct m25p	*flash = spi_mem_get_drvdata(spimem);
+	int ret;
 
 	spi_nor_restore(&flash->spi_nor);
 
 	/* Clean up MTD stuff. */
-	return mtd_device_unregister(&flash->spi_nor.mtd);
+	ret = mtd_device_unregister(&flash->spi_nor.mtd);
+	if (ret)
+		return ret;
+
+	spi_mem_dirmap_destroy(flash->dirmap.rdesc);
+	spi_mem_dirmap_destroy(flash->dirmap.wdesc);
+
+	return 0;
 }
 
 static void m25p_shutdown(struct spi_mem *spimem)

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