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From:   "Ramuthevar,Vadivel MuruganX" 
        <vadivel.muruganx.ramuthevar@linux.intel.com>
To:     linux-mtd@lists.infradead.org
Cc:     linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        dwmw2@infradead.org, computersforpeace@gmail.com, richard@nod.at,
        jwboyer@gmail.com, boris.brezillon@free-electrons.com,
        cyrille.pitchen@atmel.com, david.oberhollenzer@sigma-star.at,
        miquel.raynal@bootlin.com, tudor.ambarus@gmail.com,
        vigneshr@ti.com, andriy.shevchenko@intel.com,
        cheol.yong.kim@intel.com, qi-ming.wu@intel.com,
        Ramuthevar Vadivel Murugan 
        <vadivel.muruganx.ramuthevar@linux.intel.com>
Subject: [PATCH v4 1/2] mtd: spi-nor: cadence-quadspi: Disable the DAC for Intel LGM SoC
Date:   Thu, 17 Oct 2019 15:19:59 +0800
Message-Id: <20191017072000.48860-2-vadivel.muruganx.ramuthevar@linux.intel.com>
In-Reply-To: <20191017072000.48860-1-vadivel.muruganx.ramuthevar@linux.intel.com>
References: <20191017072000.48860-1-vadivel.muruganx.ramuthevar@linux.intel.com>
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From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>

On Intel Lightning Mountain(LGM) SoCs QSPI controller do not use
Direct Access Controller(DAC).

This patch adds a quirk to disable the Direct Access Controller
for data transfer instead it uses indirect data transfer.

Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
---
 drivers/mtd/spi-nor/Kconfig           |  2 +-
 drivers/mtd/spi-nor/cadence-quadspi.c | 33 +++++++++++++++++++++++++++------
 2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig
index f237fcdf7f86..ef1aa369c2e3 100644
--- a/drivers/mtd/spi-nor/Kconfig
+++ b/drivers/mtd/spi-nor/Kconfig
@@ -36,7 +36,7 @@ config SPI_ASPEED_SMC
 
 config SPI_CADENCE_QUADSPI
 	tristate "Cadence Quad SPI controller"
-	depends on OF && (ARM || ARM64 || COMPILE_TEST)
+	depends on OF && (ARM || ARM64 || COMPILE_TEST || X86)
 	help
 	  Enable support for the Cadence Quad SPI Flash controller.
 
diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
index 7bef63947b29..0ad076eaa81b 100644
--- a/drivers/mtd/spi-nor/cadence-quadspi.c
+++ b/drivers/mtd/spi-nor/cadence-quadspi.c
@@ -34,6 +34,7 @@
 
 /* Quirks */
 #define CQSPI_NEEDS_WR_DELAY		BIT(0)
+#define CQSPI_DISABLE_DAC_MODE		BIT(1)
 
 /* Capabilities mask */
 #define CQSPI_BASE_HWCAPS_MASK					\
@@ -600,6 +601,13 @@ static int cqspi_write_setup(struct spi_nor *nor)
 	struct cqspi_st *cqspi = f_pdata->cqspi;
 	void __iomem *reg_base = cqspi->iobase;
 
+	/* Disable direct access controller */
+	if (!f_pdata->use_direct_mode) {
+		reg = readl(reg_base + CQSPI_REG_CONFIG);
+		reg &= ~CQSPI_REG_CONFIG_ENB_DIR_ACC_CTRL;
+		writel(reg, reg_base + CQSPI_REG_CONFIG);
+	}
+
 	/* Set opcode. */
 	reg = nor->program_opcode << CQSPI_REG_WR_INSTR_OPCODE_LSB;
 	writel(reg, reg_base + CQSPI_REG_WR_INSTR);
@@ -1292,12 +1300,16 @@ static int cqspi_setup_flash(struct cqspi_st *cqspi, struct device_node *np)
 		f_pdata->registered = true;
 
 		if (mtd->size <= cqspi->ahb_size) {
-			f_pdata->use_direct_mode = true;
-			dev_dbg(nor->dev, "using direct mode for %s\n",
-				mtd->name);
-
-			if (!cqspi->rx_chan)
-				cqspi_request_mmap_dma(cqspi);
+			if (ddata && (ddata->quirks & CQSPI_DISABLE_DAC_MODE)) {
+				f_pdata->use_direct_mode = false;
+			} else {
+				f_pdata->use_direct_mode = true;
+				dev_dbg(nor->dev, "using direct mode for %s\n",
+					mtd->name);
+
+				if (!cqspi->rx_chan)
+					cqspi_request_mmap_dma(cqspi);
+			}
 		}
 	}
 
@@ -1501,6 +1513,11 @@ static const struct cqspi_driver_platdata am654_ospi = {
 	.quirks = CQSPI_NEEDS_WR_DELAY,
 };
 
+static const struct cqspi_driver_platdata intel_lgm_qspi = {
+	.hwcaps_mask = CQSPI_BASE_HWCAPS_MASK,
+	.quirks = CQSPI_DISABLE_DAC_MODE,
+};
+
 static const struct of_device_id cqspi_dt_ids[] = {
 	{
 		.compatible = "cdns,qspi-nor",
@@ -1514,6 +1531,10 @@ static const struct of_device_id cqspi_dt_ids[] = {
 		.compatible = "ti,am654-ospi",
 		.data = &am654_ospi,
 	},
+	{
+		.compatible = "intel,lgm-qspi",
+		.data = &intel_lgm_qspi,
+	},
 	{ /* end of table */ }
 };
 
-- 
2.11.0