linux-kernel - [PATCH v1 2/2] spi: spi-geni-qcom: Don't set {tx,rx}_rem

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Date:   Fri, 19 Jun 2020 19:22:33 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Mark Brown <broonie@...nel.org>
Cc:     linux-kernel@...r.kernel.org, Alok Chauhan <alokc@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, linux-spi@...r.kernel.org,
        Douglas Anderson <dianders@...omium.org>
Subject: [PATCH v1 2/2] spi: spi-geni-qcom: Don't set {tx,rx}_rem_bytes unnecessarily

We only need to test for these counters being non-zero when we see the
end of a transfer. If we're doing a CS change then they will already be
zero.  This implies that we don't need to set these to 0 if we're
cancelling an in flight transfer too, because we only care to test these
counters when the 'DONE' bit is set in the hardware and we've set them
to non-zero for a transfer.

This is a non-functional change, just cleanup to consolidate code.

Reviewed-by: Douglas Anderson <dianders@...omium.org>
Signed-off-by: Stephen Boyd <swboyd@...omium.org>
---
 drivers/spi/spi-geni-qcom.c | 42 ++++++++++++++++++-------------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
index d8f03ffb8594..5b1dca1fff79 100644
--- a/drivers/spi/spi-geni-qcom.c
+++ b/drivers/spi/spi-geni-qcom.c
@@ -122,7 +122,6 @@ static void handle_fifo_timeout(struct spi_master *spi,
 	reinit_completion(&mas->cancel_done);
 	writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
 	mas->cur_xfer = NULL;
-	mas->tx_rem_bytes = mas->rx_rem_bytes = 0;
 	geni_se_cancel_m_cmd(se);
 	spin_unlock_irq(&mas->lock);
 
@@ -513,29 +512,30 @@ static irqreturn_t geni_spi_isr(int irq, void *data)
 		if (mas->cur_xfer) {
 			spi_finalize_current_transfer(spi);
 			mas->cur_xfer = NULL;
+			/*
+			 * If this happens, then a CMD_DONE came before all the
+			 * Tx buffer bytes were sent out. This is unusual, log
+			 * this condition and disable the WM interrupt to
+			 * prevent the system from stalling due an interrupt
+			 * storm.
+			 *
+			 * If this happens when all Rx bytes haven't been
+			 * received, log the condition. The only known time
+			 * this can happen is if bits_per_word != 8 and some
+			 * registers that expect xfer lengths in num spi_words
+			 * weren't written correctly.
+			 */
+			if (mas->tx_rem_bytes) {
+				writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
+				dev_err(mas->dev, "Premature done. tx_rem = %d bpw%d\n",
+					mas->tx_rem_bytes, mas->cur_bits_per_word);
+			}
+			if (mas->rx_rem_bytes)
+				dev_err(mas->dev, "Premature done. rx_rem = %d bpw%d\n",
+					mas->rx_rem_bytes, mas->cur_bits_per_word);
 		} else {
 			complete(&mas->cs_done);
 		}
-
-		/*
-		 * If this happens, then a CMD_DONE came before all the Tx
-		 * buffer bytes were sent out. This is unusual, log this
-		 * condition and disable the WM interrupt to prevent the
-		 * system from stalling due an interrupt storm.
-		 * If this happens when all Rx bytes haven't been received, log
-		 * the condition.
-		 * The only known time this can happen is if bits_per_word != 8
-		 * and some registers that expect xfer lengths in num spi_words
-		 * weren't written correctly.
-		 */
-		if (mas->tx_rem_bytes) {
-			writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
-			dev_err(mas->dev, "Premature done. tx_rem = %d bpw%d\n",
-				mas->tx_rem_bytes, mas->cur_bits_per_word);
-		}
-		if (mas->rx_rem_bytes)
-			dev_err(mas->dev, "Premature done. rx_rem = %d bpw%d\n",
-				mas->rx_rem_bytes, mas->cur_bits_per_word);
 	}
 
 	if (m_irq & M_CMD_CANCEL_EN)
-- 
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