[PATCH v4 13/16] mtd: spinand: extract variant ranking logic into spinand_op_find_best()

[Santhosh Kumar K <s-k6@ti.com>]

spinand_select_op_variant() open-codes a loop that finds the fastest
eligible op variant by transfer duration. Extract this into a shared
helper spinand_op_find_best() that accepts a skip_mask bitmask of
already-tried variant indices, enabling callers to iterate variants in
ranked order while skipping previously attempted ones.

spinand_select_op_variant() becomes a one-liner. No functional change.

Signed-off-by: Santhosh Kumar K <s-k6@ti.com>
---
 drivers/mtd/nand/spi/core.c | 32 +++++++++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index f86786344d52..b678d0534297 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -1541,9 +1541,22 @@ static int spinand_init_odtr_instruction_set(struct spinand_device *spinand)
 	return 0;
 }
 
+/*
+ * spinand_op_find_best() - Find the fastest eligible op variant.
+ * @spinand:    SPI NAND device
+ * @variants:   full variant list to search
+ * @odtr:       true to consider ODTR ops, false for SSDR ops
+ * @skip_mask:  bitmask of variant indices to skip (already tried)
+ *
+ * Iterates @variants, evaluates transfer duration for each eligible op, and
+ * returns a pointer to the fastest one not in @skip_mask.  Returns NULL when
+ * no eligible variant remains.  Used by both variant selection at init time
+ * (skip_mask == 0) and ranked PHY tuning iteration.
+ */
 static const struct spi_mem_op *
-spinand_select_op_variant(struct spinand_device *spinand, enum spinand_bus_interface iface,
-			  const struct spinand_op_variants *variants)
+spinand_op_find_best(struct spinand_device *spinand,
+		     const struct spinand_op_variants *variants, bool odtr,
+		     u32 skip_mask)
 {
 	struct nand_device *nand = spinand_to_nand(spinand);
 	const struct spi_mem_op *best_variant = NULL;
@@ -1551,15 +1564,16 @@ spinand_select_op_variant(struct spinand_device *spinand, enum spinand_bus_inter
 	unsigned int i;
 
 	for (i = 0; i < variants->nops; i++) {
-		struct spi_mem_op op = variants->ops[i];
+		struct spi_mem_op op;
 		u64 op_duration_ns = 0;
 		unsigned int nbytes;
 		int ret;
 
-		if ((iface == SSDR && spinand_op_is_odtr(&op)) ||
-		    (iface == ODTR && !spinand_op_is_odtr(&op)))
+		if ((skip_mask & BIT(i)) ||
+		    spinand_op_is_odtr(&variants->ops[i]) != odtr)
 			continue;
 
+		op = variants->ops[i];
 		nbytes = nanddev_per_page_oobsize(nand) +
 			 nanddev_page_size(nand);
 
@@ -1588,6 +1602,14 @@ spinand_select_op_variant(struct spinand_device *spinand, enum spinand_bus_inter
 	return best_variant;
 }
 
+static const struct spi_mem_op *
+spinand_select_op_variant(struct spinand_device *spinand,
+			  enum spinand_bus_interface iface,
+			  const struct spinand_op_variants *variants)
+{
+	return spinand_op_find_best(spinand, variants, iface == ODTR, 0);
+}
+
 /**
  * spinand_match_and_init() - Try to find a match between a device ID and an
  *			      entry in a spinand_info table
-- 
2.34.1