spi: cadence-quadspi: Add flag for direct mode writes

Create new flag inorder to avoid playing with use_direct_mode
flag currently being used throughout the driver.
Disable DAC write if auto polling is disabled or CQSPI_DISABLE_DAC_MODE
is set.
Signed-off-by: Dhruva Gole <d-gole@ti.com>
Link: https://lore.kernel.org/r/20230125081023.1573712-3-d-gole@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-cadence-quadspi.c

@@ -84,6 +84,7 @@ struct cqspi_st {
 	u32			trigger_address;
 	u32			wr_delay;
 	bool			use_direct_mode;
+	bool			use_direct_mode_wr;
 	struct cqspi_flash_pdata f_pdata[CQSPI_MAX_CHIPSELECT];
 	bool			use_dma_read;
 	u32			pd_dev_id;
@@ -945,6 +946,12 @@ static int cqspi_write_setup(struct cqspi_flash_pdata *f_pdata,
 		reg = readl(reg_base + CQSPI_REG_WR_COMPLETION_CTRL);
 		reg |= CQSPI_REG_WR_DISABLE_AUTO_POLL;
 		writel(reg, reg_base + CQSPI_REG_WR_COMPLETION_CTRL);
+		/*
+		 * DAC mode require auto polling as flash needs to be polled
+		 * for write completion in case of bubble in SPI transaction
+		 * due to slow CPU/DMA master.
+		 */
+		cqspi->use_direct_mode_wr = false;
 	}
 
 	reg = readl(reg_base + CQSPI_REG_SIZE);
@@ -1230,7 +1237,7 @@ static ssize_t cqspi_write(struct cqspi_flash_pdata *f_pdata,
 	 * data.
 	 */
 	if (!op->cmd.dtr && cqspi->use_direct_mode &&
-	    ((to + len) <= cqspi->ahb_size)) {
+	    cqspi->use_direct_mode_wr && ((to + len) <= cqspi->ahb_size)) {
 		memcpy_toio(cqspi->ahb_base + to, buf, len);
 		return cqspi_wait_idle(cqspi);
 	}
@@ -1700,8 +1707,10 @@ static int cqspi_probe(struct platform_device *pdev)
 						cqspi->master_ref_clk_hz);
 		if (ddata->hwcaps_mask & CQSPI_SUPPORTS_OCTAL)
 			master->mode_bits |= SPI_RX_OCTAL | SPI_TX_OCTAL;
-		if (!(ddata->quirks & CQSPI_DISABLE_DAC_MODE))
+		if (!(ddata->quirks & CQSPI_DISABLE_DAC_MODE)) {
 			cqspi->use_direct_mode = true;
+			cqspi->use_direct_mode_wr = true;
+		}
 		if (ddata->quirks & CQSPI_SUPPORT_EXTERNAL_DMA)
 			cqspi->use_dma_read = true;
 		if (ddata->quirks & CQSPI_NO_SUPPORT_WR_COMPLETION)