memory: omap-gpmc: Add support for GPMC on AM64 SoC

The TI's AM64 SoC has the GPMC module. Add compatible for it.

Traditionally GPMC external addresses have always been mapped to first
1GB physical address. However newer platforms, can have it mapped
at different locations. Support this address provision via device tree.
Signed-off-by: Roger Quadros <rogerq@kernel.org>
Link: https://lore.kernel.org/r/20211221131757.2030-3-rogerq@kernel.orgSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>

drivers/memory/omap-gpmc.c

@@ -237,6 +237,7 @@ struct gpmc_device {
 	struct omap3_gpmc_regs context;
 	int nirqs;
 	unsigned int is_suspended:1;
+	struct resource *data;
 };
 
 static struct irq_domain *gpmc_irq_domain;
@@ -1456,12 +1457,18 @@ static void gpmc_mem_exit(void)
 	}
 }
 
-static void gpmc_mem_init(void)
+static void gpmc_mem_init(struct gpmc_device *gpmc)
 {
 	int cs;
 
+	if (!gpmc->data) {
+		/* All legacy devices have same data IO window */
 		gpmc_mem_root.start = GPMC_MEM_START;
 		gpmc_mem_root.end = GPMC_MEM_END;
+	} else {
+		gpmc_mem_root.start = gpmc->data->start;
+		gpmc_mem_root.end = gpmc->data->end;
+	}
 
 	/* Reserve all regions that has been set up by bootloader */
 	for (cs = 0; cs < gpmc_cs_num; cs++) {
@@ -1888,6 +1895,7 @@ static const struct of_device_id gpmc_dt_ids[] = {
 	{ .compatible = "ti,omap3430-gpmc" },	/* omap3430 & omap3630 */
 	{ .compatible = "ti,omap4430-gpmc" },	/* omap4430 & omap4460 & omap543x */
 	{ .compatible = "ti,am3352-gpmc" },	/* am335x devices */
+	{ .compatible = "ti,am64-gpmc" },
 	{ }
 };
 
@@ -2502,14 +2510,26 @@ static int gpmc_probe(struct platform_device *pdev)
 	gpmc->dev = &pdev->dev;
 	platform_set_drvdata(pdev, gpmc);
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!res)
-		return -ENOENT;
-
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg");
+	if (!res) {
+		/* legacy DT */
+		gpmc_base = devm_platform_ioremap_resource(pdev, 0);
+		if (IS_ERR(gpmc_base))
+			return PTR_ERR(gpmc_base);
+	} else {
 		gpmc_base = devm_ioremap_resource(&pdev->dev, res);
 		if (IS_ERR(gpmc_base))
 			return PTR_ERR(gpmc_base);
 
+		res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "data");
+		if (!res) {
+			dev_err(&pdev->dev, "couldn't get data reg resource\n");
+			return -ENOENT;
+		}
+
+		gpmc->data = res;
+	}
+
 	gpmc->irq = platform_get_irq(pdev, 0);
 	if (gpmc->irq < 0)
 		return gpmc->irq;
@@ -2558,7 +2578,7 @@ static int gpmc_probe(struct platform_device *pdev)
 	dev_info(gpmc->dev, "GPMC revision %d.%d\n", GPMC_REVISION_MAJOR(l),
 		 GPMC_REVISION_MINOR(l));
 
-	gpmc_mem_init();
+	gpmc_mem_init(gpmc);
 	rc = gpmc_gpio_init(gpmc);
 	if (rc)
 		goto gpio_init_failed;