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From:   Sudip Mukherjee <sudip.mukherjee@sifive.com>
To:     Serge Semin <fancer.lancer@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
Cc:     jude.onyenegecha@sifive.com, ben.dooks@sifive.com,
        jeegar.lakhani@sifive.com, linux-spi@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Sudip Mukherjee <sudip.mukherjee@sifive.com>
Subject: [PATCH v2 10/15] spi: dw: Calculate Receive FIFO Threshold Level
Date:   Mon, 12 Dec 2022 18:07:27 +0000
Message-Id: <20221212180732.79167-11-sudip.mukherjee@sifive.com>
In-Reply-To: <20221212180732.79167-1-sudip.mukherjee@sifive.com>
References: <20221212180732.79167-1-sudip.mukherjee@sifive.com>
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In enhanced mode we need to calculate RXFTLR based on the length of data
we are expecting to receive or the fifo length.

Signed-off-by: Sudip Mukherjee <sudip.mukherjee@sifive.com>
---
 drivers/spi/spi-dw-core.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
index 10d453228368f..75f5ce5f377ca 100644
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -428,6 +428,14 @@ static void dw_spi_irq_setup(struct dw_spi *dws,
 	 */
 	level = min_t(u16, dws->fifo_len / 2, dws->tx_len);
 	dw_writel(dws, DW_SPI_TXFTLR, level);
+
+	/*
+	 * In enhanced mode if we are reading then tx_len is 0 as we
+	 * have nothing to transmit. Calculate DW_SPI_RXFTLR with
+	 * rx_len.
+	 */
+	if (t_handler == dw_spi_enh_handler)
+		level = min_t(u16, dws->fifo_len / 2, dws->rx_len);
 	dw_writel(dws, DW_SPI_RXFTLR, level - 1);
 
 	dws->transfer_handler = t_handler;
-- 
2.30.2