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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 09/15] spi: dw: use irq handler for enhanced spi
Date:   Mon, 12 Dec 2022 18:07:26 +0000
Message-Id: <20221212180732.79167-10-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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Introduce the interrupt handler for enhanced spi to read or write based
on the generated irq. Also, use the xfer_completion from spi_controller
to wait for a timeout or completion from irq handler.

Signed-off-by: Sudip Mukherjee <sudip.mukherjee@sifive.com>
---
 drivers/spi/spi-dw-core.c | 62 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
index f540165245a89..10d453228368f 100644
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -251,6 +251,34 @@ static irqreturn_t dw_spi_transfer_handler(struct dw_spi *dws)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t dw_spi_enh_handler(struct dw_spi *dws)
+{
+	u16 irq_status = dw_readl(dws, DW_SPI_ISR);
+
+	if (dw_spi_check_status(dws, false)) {
+		spi_finalize_current_transfer(dws->master);
+		return IRQ_HANDLED;
+	}
+
+	if (irq_status & DW_SPI_INT_RXFI) {
+		dw_reader(dws);
+		if (dws->rx_len <= dw_readl(dws, DW_SPI_RXFTLR))
+			dw_writel(dws, DW_SPI_RXFTLR, dws->rx_len - 1);
+	}
+
+	if (irq_status & DW_SPI_INT_TXEI)
+		dw_writer(dws);
+
+	if (!dws->tx_len && dws->rx_len) {
+		dw_spi_mask_intr(dws, DW_SPI_INT_TXEI);
+	} else if (!dws->rx_len && !dws->tx_len) {
+		dw_spi_mask_intr(dws, 0xff);
+		spi_finalize_current_transfer(dws->master);
+	}
+
+	return IRQ_HANDLED;
+}
+
 static irqreturn_t dw_spi_irq(int irq, void *dev_id)
 {
 	struct spi_controller *master = dev_id;
@@ -265,6 +293,12 @@ static irqreturn_t dw_spi_irq(int irq, void *dev_id)
 		dw_spi_mask_intr(dws, 0xff);
 		return IRQ_HANDLED;
 	}
+	if ((dws->transfer_handler == dw_spi_enh_handler &&
+	     !dws->rx_len && !dws->tx_len)) {
+		dw_spi_mask_intr(dws, 0xff);
+		spi_finalize_current_transfer(master);
+		return IRQ_HANDLED;
+	}
 
 	return dws->transfer_handler(dws);
 }
@@ -862,6 +896,8 @@ static int dw_spi_exec_enh_mem_op(struct spi_mem *mem, const struct spi_mem_op *
 	struct spi_controller *ctlr = mem->spi->controller;
 	struct dw_spi *dws = spi_controller_get_devdata(ctlr);
 	struct dw_spi_cfg cfg;
+	int ret = 0;
+	unsigned long long ms;
 
 	switch (op->data.buswidth) {
 	case 2:
@@ -909,11 +945,35 @@ static int dw_spi_exec_enh_mem_op(struct spi_mem *mem, const struct spi_mem_op *
 
 	dw_spi_update_config(dws, mem->spi, &cfg);
 
+	dw_spi_mask_intr(dws, 0xff);
+	reinit_completion(&ctlr->xfer_completion);
 	dw_spi_enable_chip(dws, 1);
 
 	dw_spi_enh_write_cmd_addr(dws, op);
+	dw_spi_set_cs(mem->spi, false);
+	dw_spi_irq_setup(dws, dw_spi_enh_handler);
 
-	return 0;
+	/* Use timeout calculation from spi_transfer_wait() */
+	ms = 8LL * MSEC_PER_SEC * (dws->rx_len ? dws->rx_len : dws->tx_len);
+	do_div(ms, dws->current_freq);
+
+	/*
+	 * Increase it twice and add 200 ms tolerance, use
+	 * predefined maximum in case of overflow.
+	 */
+	ms += ms + 200;
+	if (ms > UINT_MAX)
+		ms = UINT_MAX;
+
+	ms = wait_for_completion_timeout(&ctlr->xfer_completion,
+					 msecs_to_jiffies(ms));
+
+	dw_spi_stop_mem_op(dws, mem->spi);
+
+	if (ms == 0)
+		ret = -EIO;
+
+	return ret;
 }
 
 /*
-- 
2.30.2