mtd: spinand: Drop ECC dirmaps

Direct mappings are very static concepts, which allow us to reuse a
template to perform reads or writes in a very efficient manner after a
single initialization. With the introduction of pipelined ECC engines
for SPI controllers, the need to differentiate between an operation with
and without correction has arised. The chosen solution at that time has
been to create new direct mappings for these operations, jumping from 2
to 4 dirmaps per target. Enabling ECC was done by choosing the correct
dirmap.

Today, we need to further parametrize dirmaps. With the goal to enable
continuous reads on a wider range of devices, we will need more
flexibility regarding the read from cache operation template to pick at
run time, for instance to use shorter "continuous read from cache"
variants.

We could create other direct mappings, but it would increase the matrix
by a power of two, bringing the theoretical number of dirmaps to
8 (read/write, ecc, shorter read variants) per target. This grow is not
sustainable, so let's change how dirmaps work - a little bit.

Operations already carry an ECC parameter, use it to indicate whether
error correction is required or not. In practice this change happens
only at the core level, SPI controller drivers do not care about the
direct mapping structure in this case, they just pick whatever is in the
template as a base. As a result, we allow the core to dynamically change
the content of the templates.

He who can do more can do less, so during the checking steps, make sure
to enable the ECC requirement just for the time of the checks.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index a8247e5720c39c433fddf8819fbc1e2a1ccce538..0f154260e70fce6e941548b0346f764dd703e71c 100644 (file)
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -487,10 +487,13 @@ static int spinand_read_from_cache_op(struct spinand_device *spinand,
                }
        }
 
-       if (req->mode == MTD_OPS_RAW)
-               rdesc = spinand->dirmaps[req->pos.plane].rdesc;
+       rdesc = spinand->dirmaps[req->pos.plane].rdesc;
+
+       if (nand->ecc.engine->integration == NAND_ECC_ENGINE_INTEGRATION_PIPELINED &&
+           req->mode != MTD_OPS_RAW)
+               rdesc->info.op_tmpl.data.ecc = true;
        else
-               rdesc = spinand->dirmaps[req->pos.plane].rdesc_ecc;
+               rdesc->info.op_tmpl.data.ecc = false;
 
        if (spinand->flags & SPINAND_HAS_READ_PLANE_SELECT_BIT)
                column |= req->pos.plane << fls(nanddev_page_size(nand));
@@ -579,10 +582,13 @@ static int spinand_write_to_cache_op(struct spinand_device *spinand,
                               req->ooblen);
        }
 
-       if (req->mode == MTD_OPS_RAW)
-               wdesc = spinand->dirmaps[req->pos.plane].wdesc;
+       wdesc = spinand->dirmaps[req->pos.plane].wdesc;
+
+       if (nand->ecc.engine->integration == NAND_ECC_ENGINE_INTEGRATION_PIPELINED &&
+           req->mode != MTD_OPS_RAW)
+               wdesc->info.op_tmpl.data.ecc = true;
        else
-               wdesc = spinand->dirmaps[req->pos.plane].wdesc_ecc;
+               wdesc->info.op_tmpl.data.ecc = false;
 
        if (spinand->flags & SPINAND_HAS_PROG_PLANE_SELECT_BIT)
                column |= req->pos.plane << fls(nanddev_page_size(nand));
@@ -1231,12 +1237,17 @@ static int spinand_create_dirmap(struct spinand_device *spinand,
        struct nand_device *nand = spinand_to_nand(spinand);
        struct spi_mem_dirmap_info info = { 0 };
        struct spi_mem_dirmap_desc *desc;
+       bool enable_ecc = false;
+
+       if (nand->ecc.engine->integration == NAND_ECC_ENGINE_INTEGRATION_PIPELINED)
+               enable_ecc = true;
 
        /* The plane number is passed in MSB just above the column address */
        info.offset = plane << fls(nand->memorg.pagesize);
 
+       /* Write descriptor */
        info.length = nanddev_page_size(nand) + nanddev_per_page_oobsize(nand);
-       info.op_tmpl = *spinand->op_templates->update_cache;
+       info.op_tmpl.data.ecc = enable_ecc;
        desc = devm_spi_mem_dirmap_create(&spinand->spimem->spi->dev,
                                          spinand->spimem, &info);
        if (IS_ERR(desc))
@@ -1244,38 +1255,15 @@ static int spinand_create_dirmap(struct spinand_device *spinand,
 
        spinand->dirmaps[plane].wdesc = desc;
 
+       /* Read descriptor */
        info.op_tmpl = *spinand->op_templates->read_cache;
+       info.op_tmpl.data.ecc = enable_ecc;
        desc = spinand_create_rdesc(spinand, &info);
        if (IS_ERR(desc))
                return PTR_ERR(desc);
 
        spinand->dirmaps[plane].rdesc = desc;
 
-       if (nand->ecc.engine->integration != NAND_ECC_ENGINE_INTEGRATION_PIPELINED) {
-               spinand->dirmaps[plane].wdesc_ecc = spinand->dirmaps[plane].wdesc;
-               spinand->dirmaps[plane].rdesc_ecc = spinand->dirmaps[plane].rdesc;
-
-               return 0;
-       }
-
-       info.length = nanddev_page_size(nand) + nanddev_per_page_oobsize(nand);
-       info.op_tmpl = *spinand->op_templates->update_cache;
-       info.op_tmpl.data.ecc = true;
-       desc = devm_spi_mem_dirmap_create(&spinand->spimem->spi->dev,
-                                         spinand->spimem, &info);
-       if (IS_ERR(desc))
-               return PTR_ERR(desc);
-
-       spinand->dirmaps[plane].wdesc_ecc = desc;
-
-       info.op_tmpl = *spinand->op_templates->read_cache;
-       info.op_tmpl.data.ecc = true;
-       desc = spinand_create_rdesc(spinand, &info);
-       if (IS_ERR(desc))
-               return PTR_ERR(desc);
-
-       spinand->dirmaps[plane].rdesc_ecc = desc;
-
        return 0;
 }
 

diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
index e1f19664bb2541d2ff6eaa4a0c0d1665afb6d478..896e9b5de0c41f95b3a3da7811b2557a5678b130 100644 (file)
--- a/include/linux/mtd/spinand.h
+++ b/include/linux/mtd/spinand.h
@@ -684,8 +684,6 @@ struct spinand_info {
 struct spinand_dirmap {
        struct spi_mem_dirmap_desc *wdesc;
        struct spi_mem_dirmap_desc *rdesc;
-       struct spi_mem_dirmap_desc *wdesc_ecc;
-       struct spi_mem_dirmap_desc *rdesc_ecc;
 };
 
 /**