[regression 5.4.y][RFC][PATCH mtd: rawnand: gpmi: busy_timeout_cycles 1/1] Revert "Revert "mtd: rawnand: gpmi: Fix setting busy timeout setting""

[max.oss.09@gmail.com]

From: Max Krummenacher <max.krummenacher@toradex.com>

This reverts commit 15a3adfe75937c9e4e0e48f0ed40dd39a0e526e2.

The backport of [1] relies on having [2] also backported. Having only
one of the two results in a bogus hw->timing1 setting.

If only [2] is backportet the 16 bit register value likely underflows
resulting in a busy_wait_timeout of 0.
Or if only [1] is applied the value likely overflows with chances of
having last 16 LSBs all 0 which would then result in a
busy_wait_timeout of 0 too.

Both cases may lead to NAND data corruption, e.g. on a Colibri iMX7
setup this has been seen.

[1] commit 0fddf9ad06fd ("mtd: rawnand: gpmi: Set WAIT_FOR_READY
timeout based on program/erase times")
[2] commit 06781a5026350 ("mtd: rawnand: gpmi: Fix setting busy
timeout setting")

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
---
 drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
index b806a762d079f..fdf5cf5565f99 100644
--- a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
+++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
@@ -684,7 +684,7 @@ static void gpmi_nfc_compute_timings(struct gpmi_nand_data *this,
 	hw->timing0 = BF_GPMI_TIMING0_ADDRESS_SETUP(addr_setup_cycles) |
 		      BF_GPMI_TIMING0_DATA_HOLD(data_hold_cycles) |
 		      BF_GPMI_TIMING0_DATA_SETUP(data_setup_cycles);
-	hw->timing1 = BF_GPMI_TIMING1_BUSY_TIMEOUT(busy_timeout_cycles * 4096);
+	hw->timing1 = BF_GPMI_TIMING1_BUSY_TIMEOUT(DIV_ROUND_UP(busy_timeout_cycles, 4096));
 
 	/*
 	 * Derive NFC ideal delay from {3}:
-- 
2.42.0


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