spi: cadence-qspi: reset qspi flash for versal platform

When flash operated at non default mode like DDR, flash need to be reset
to operate in SDR mode to read flash ids by spi-nor framework. Reset the
flash to the default state before using the flash. This reset is handled
by a gpio driver, in case of mini U-Boot as gpio driver is disabled, we
do raw read and write access by the registers.
Versal platform utilizes spi calibration for read delay programming, so
incase by default read delay property is set in DT. We make sure not to
use read delay from DT by overwriting read_delay with -1.

Signed-off-by: T Karthik Reddy <t.karthik.reddy@xilinx.com>
Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Link: https://lore.kernel.org/r/20220512100535.16364-4-ashok.reddy.soma@xilinx.com
Signed-off-by: Michal Simek <michal.simek@amd.com>
diff --git a/drivers/spi/cadence_ospi_versal.c b/drivers/spi/cadence_ospi_versal.c
index 4b13beb..0caf250 100644
--- a/drivers/spi/cadence_ospi_versal.c
+++ b/drivers/spi/cadence_ospi_versal.c
@@ -125,3 +125,89 @@
 	       plat->regbase + CQSPI_DMA_DST_I_STS_REG);
 	return 0;
 }
+
+#if defined(CONFIG_DM_GPIO)
+int cadence_spi_versal_flash_reset(struct udevice *dev)
+{
+	struct gpio_desc gpio;
+	u32 reset_gpio;
+	int ret;
+
+	/* request gpio and set direction as output set to 1 */
+	ret = gpio_request_by_name(dev, "reset-gpios", 0, &gpio,
+				   GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
+	if (ret) {
+		printf("%s: unable to reset ospi flash device", __func__);
+		return ret;
+	}
+
+	reset_gpio = PMIO_NODE_ID_BASE + gpio.offset;
+
+	/* Request for pin */
+	xilinx_pm_request(PM_PINCTRL_REQUEST, reset_gpio, 0, 0, 0, NULL);
+
+	/* Enable hysteresis in cmos receiver */
+	xilinx_pm_request(PM_PINCTRL_CONFIG_PARAM_SET, reset_gpio,
+			  PM_PINCTRL_CONFIG_SCHMITT_CMOS,
+			  PM_PINCTRL_INPUT_TYPE_SCHMITT, 0, NULL);
+
+	/* Disable Tri-state */
+	xilinx_pm_request(PM_PINCTRL_CONFIG_PARAM_SET, reset_gpio,
+			  PM_PINCTRL_CONFIG_TRI_STATE,
+			  PM_PINCTRL_TRI_STATE_DISABLE, 0, NULL);
+	udelay(1);
+
+	/* Set value 0 to pin */
+	dm_gpio_set_value(&gpio, 0);
+	udelay(1);
+
+	/* Set value 1 to pin */
+	dm_gpio_set_value(&gpio, 1);
+	udelay(1);
+
+	return 0;
+}
+#else
+int cadence_spi_versal_flash_reset(struct udevice *dev)
+{
+	/* CRP WPROT */
+	writel(0, WPROT_CRP);
+	/* GPIO Reset */
+	writel(0, RST_GPIO);
+
+	/* disable IOU write protection */
+	writel(0, WPROT_LPD_MIO);
+
+	/* set direction as output */
+	writel((readl(BOOT_MODE_DIR) | BIT(FLASH_RESET_GPIO)),
+	       BOOT_MODE_POR_0);
+
+	/* Data output enable */
+	writel((readl(BOOT_MODE_OUT) | BIT(FLASH_RESET_GPIO)),
+	       BOOT_MODE_POR_1);
+
+	/* IOU SLCR write enable */
+	writel(0, WPROT_PMC_MIO);
+
+	/* set MIO as GPIO */
+	writel(0x60, MIO_PIN_12);
+
+	/* Set value 1 to pin */
+	writel((readl(BANK0_OUTPUT) | BIT(FLASH_RESET_GPIO)), BANK0_OUTPUT);
+	udelay(10);
+
+	/* Disable Tri-state */
+	writel((readl(BANK0_TRI) & ~BIT(FLASH_RESET_GPIO)), BANK0_TRI);
+	udelay(1);
+
+	/* Set value 0 to pin */
+	writel((readl(BANK0_OUTPUT) & ~BIT(FLASH_RESET_GPIO)), BANK0_OUTPUT);
+	udelay(10);
+
+	/* Set value 1 to pin */
+	writel((readl(BANK0_OUTPUT) | BIT(FLASH_RESET_GPIO)), BANK0_OUTPUT);
+	udelay(10);
+
+	return 0;
+}
+#endif