[PATCH 1/2] spi: ich: Limit slave->max_read_size

[Bin Meng <bmeng.cn@gmail.com>]

Since commit 43c145b8b3ee ("spi: ich: Correct max-size bug in ich_spi_adjust_size()")
(in v2020.04-rc1), SPI flash read no longer works with ICH SPI controller
in software sequencer mode.

ICH controller can only transfer a small number of bytes at once.
Before commit 43c145b8b3ee, the logic happens to make sure data.nbytes
is limited to slave->max_write_size but after commit 43c145b8b3ee
data.nbytes is no longer limited because slave->max_read_size is not
initialized with a valid number.

Fixes: 43c145b8b3ee ("spi: ich: Correct max-size bug in ich_spi_adjust_size()")
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
---

 drivers/spi/ich.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/ich.c b/drivers/spi/ich.c
index 3d49c22a9d..08d54e86f4 100644
--- a/drivers/spi/ich.c
+++ b/drivers/spi/ich.c
@@ -918,12 +918,14 @@ static int ich_spi_child_pre_probe(struct udevice *dev)
 	struct spi_slave *slave = dev_get_parent_priv(dev);
 
 	/*
-	 * Yes this controller can only write a small number of bytes at
+	 * Yes this controller can only transfer a small number of bytes at
 	 * once! The limit is typically 64 bytes. For hardware sequencing a
 	 * a loop is used to get around this.
 	 */
-	if (!plat->hwseq)
+	if (!plat->hwseq) {
+		slave->max_read_size = priv->databytes;
 		slave->max_write_size = priv->databytes;
+	}
 	/*
 	 * ICH 7 SPI controller only supports array read command
 	 * and byte program command for SST flash
-- 
2.25.1