memory: add ARM PL172 MultiPort Memory Controller driver

This driver makes it possible to configure the static memory
chip selects on the ARM PL172 MultiPort Memory Controller
from a set of properties in DT. Configuration of dynamic
memory is not supported and is left to the boot loader.

The intended usage is to setup timing and configuration for
static memory devices like NAND and NOR Flash before they
are probed by a driver.
Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

drivers/memory/Kconfig

@@ -7,6 +7,14 @@ menuconfig MEMORY
 
 if MEMORY
 
+config ARM_PL172_MPMC
+	tristate "ARM PL172 MPMC driver"
+	depends on ARM_AMBA && OF
+	help
+	  This selects the ARM PrimeCell PL172 MultiPort Memory Controller.
+	  If you have an embedded system with an AMBA bus and a PL172
+	  controller, say Y or M here.
+
 config ATMEL_SDRAMC
 	bool "Atmel (Multi-port DDR-)SDRAM Controller"
 	default y

drivers/memory/Makefile

@@ -5,6 +5,7 @@
 ifeq ($(CONFIG_DDR),y)
 obj-$(CONFIG_OF)		+= of_memory.o
 endif
+obj-$(CONFIG_ARM_PL172_MPMC)	+= pl172.o
 obj-$(CONFIG_ATMEL_SDRAMC)	+= atmel-sdramc.o
 obj-$(CONFIG_TI_AEMIF)		+= ti-aemif.o
 obj-$(CONFIG_TI_EMIF)		+= emif.o

drivers/memory/pl172.c

+/*
+ * Memory controller driver for ARM PrimeCell PL172
+ * PrimeCell MultiPort Memory Controller (PL172)
+ *
+ * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
+ *
+ * Based on:
+ * TI AEMIF driver, Copyright (C) 2010 - 2013 Texas Instruments Inc.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/amba/bus.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/time.h>
+
+#define MPMC_STATIC_CFG(n)		(0x200 + 0x20 * n)
+#define  MPMC_STATIC_CFG_MW_8BIT	0x0
+#define  MPMC_STATIC_CFG_MW_16BIT	0x1
+#define  MPMC_STATIC_CFG_MW_32BIT	0x2
+#define  MPMC_STATIC_CFG_PM		BIT(3)
+#define  MPMC_STATIC_CFG_PC		BIT(6)
+#define  MPMC_STATIC_CFG_PB		BIT(7)
+#define  MPMC_STATIC_CFG_EW		BIT(8)
+#define  MPMC_STATIC_CFG_B		BIT(19)
+#define  MPMC_STATIC_CFG_P		BIT(20)
+#define MPMC_STATIC_WAIT_WEN(n)		(0x204 + 0x20 * n)
+#define  MPMC_STATIC_WAIT_WEN_MAX	0x0f
+#define MPMC_STATIC_WAIT_OEN(n)		(0x208 + 0x20 * n)
+#define  MPMC_STATIC_WAIT_OEN_MAX	0x0f
+#define MPMC_STATIC_WAIT_RD(n)		(0x20c + 0x20 * n)
+#define  MPMC_STATIC_WAIT_RD_MAX	0x1f
+#define MPMC_STATIC_WAIT_PAGE(n)	(0x210 + 0x20 * n)
+#define  MPMC_STATIC_WAIT_PAGE_MAX	0x1f
+#define MPMC_STATIC_WAIT_WR(n)		(0x214 + 0x20 * n)
+#define  MPMC_STATIC_WAIT_WR_MAX	0x1f
+#define MPMC_STATIC_WAIT_TURN(n)	(0x218 + 0x20 * n)
+#define  MPMC_STATIC_WAIT_TURN_MAX	0x0f
+
+/* Maximum number of static chip selects */
+#define PL172_MAX_CS		4
+
+struct pl172_data {
+	void __iomem *base;
+	unsigned long rate;
+	struct clk *clk;
+};
+
+static int pl172_timing_prop(struct amba_device *adev,
+			     const struct device_node *np, const char *name,
+			     u32 reg_offset, u32 max, int start)
+{
+	struct pl172_data *pl172 = amba_get_drvdata(adev);
+	int cycles;
+	u32 val;
+
+	if (!of_property_read_u32(np, name, &val)) {
+		cycles = DIV_ROUND_UP(val * pl172->rate, NSEC_PER_MSEC) - start;
+		if (cycles < 0) {
+			cycles = 0;
+		} else if (cycles > max) {
+			dev_err(&adev->dev, "%s timing too tight\n", name);
+			return -EINVAL;
+		}
+
+		writel(cycles, pl172->base + reg_offset);
+	}
+
+	dev_dbg(&adev->dev, "%s: %u cycle(s)\n", name, start +
+				readl(pl172->base + reg_offset));
+
+	return 0;
+}
+
+static int pl172_setup_static(struct amba_device *adev,
+			      struct device_node *np, u32 cs)
+{
+	struct pl172_data *pl172 = amba_get_drvdata(adev);
+	u32 cfg;
+	int ret;
+
+	/* MPMC static memory configuration */
+	if (!of_property_read_u32(np, "mpmc,memory-width", &cfg)) {
+		if (cfg == 8) {
+			cfg = MPMC_STATIC_CFG_MW_8BIT;
+		} else if (cfg == 16) {
+			cfg = MPMC_STATIC_CFG_MW_16BIT;
+		} else if (cfg == 32) {
+			cfg = MPMC_STATIC_CFG_MW_32BIT;
+		} else {
+			dev_err(&adev->dev, "invalid memory width cs%u\n", cs);
+			return -EINVAL;
+		}
+	} else {
+		dev_err(&adev->dev, "memory-width property required\n");
+		return -EINVAL;
+	}
+
+	if (of_property_read_bool(np, "mpmc,async-page-mode"))
+		cfg |= MPMC_STATIC_CFG_PM;
+
+	if (of_property_read_bool(np, "mpmc,cs-active-high"))
+		cfg |= MPMC_STATIC_CFG_PC;
+
+	if (of_property_read_bool(np, "mpmc,byte-lane-low"))
+		cfg |= MPMC_STATIC_CFG_PB;
+
+	if (of_property_read_bool(np, "mpmc,extended-wait"))
+		cfg |= MPMC_STATIC_CFG_EW;
+
+	if (of_property_read_bool(np, "mpmc,buffer-enable"))
+		cfg |= MPMC_STATIC_CFG_B;
+
+	if (of_property_read_bool(np, "mpmc,write-protect"))
+		cfg |= MPMC_STATIC_CFG_P;
+
+	writel(cfg, pl172->base + MPMC_STATIC_CFG(cs));
+	dev_dbg(&adev->dev, "mpmc static config cs%u: 0x%08x\n", cs, cfg);
+
+	/* MPMC static memory timing */
+	ret = pl172_timing_prop(adev, np, "mpmc,write-enable-delay",
+				MPMC_STATIC_WAIT_WEN(cs),
+				MPMC_STATIC_WAIT_WEN_MAX, 1);
+	if (ret)
+		goto fail;
+
+	ret = pl172_timing_prop(adev, np, "mpmc,output-enable-delay",
+				MPMC_STATIC_WAIT_OEN(cs),
+				MPMC_STATIC_WAIT_OEN_MAX, 0);
+	if (ret)
+		goto fail;
+
+	ret = pl172_timing_prop(adev, np, "mpmc,read-access-delay",
+				MPMC_STATIC_WAIT_RD(cs),
+				MPMC_STATIC_WAIT_RD_MAX, 1);
+	if (ret)
+		goto fail;
+
+	ret = pl172_timing_prop(adev, np, "mpmc,page-mode-read-delay",
+				MPMC_STATIC_WAIT_PAGE(cs),
+				MPMC_STATIC_WAIT_PAGE_MAX, 1);
+	if (ret)
+		goto fail;
+
+	ret = pl172_timing_prop(adev, np, "mpmc,write-access-delay",
+				MPMC_STATIC_WAIT_WR(cs),
+				MPMC_STATIC_WAIT_WR_MAX, 2);
+	if (ret)
+		goto fail;
+
+	ret = pl172_timing_prop(adev, np, "mpmc,turn-round-delay",
+				MPMC_STATIC_WAIT_TURN(cs),
+				MPMC_STATIC_WAIT_TURN_MAX, 1);
+	if (ret)
+		goto fail;
+
+	return 0;
+fail:
+	dev_err(&adev->dev, "failed to configure cs%u\n", cs);
+	return ret;
+}
+
+static int pl172_parse_cs_config(struct amba_device *adev,
+				 struct device_node *np)
+{
+	u32 cs;
+
+	if (!of_property_read_u32(np, "mpmc,cs", &cs)) {
+		if (cs >= PL172_MAX_CS) {
+			dev_err(&adev->dev, "cs%u invalid\n", cs);
+			return -EINVAL;
+		}
+
+		return pl172_setup_static(adev, np, cs);
+	}
+
+	dev_err(&adev->dev, "cs property required\n");
+
+	return -EINVAL;
+}
+
+static const char * const pl172_revisions[] = {"r1", "r2", "r2p3", "r2p4"};
+
+static int pl172_probe(struct amba_device *adev, const struct amba_id *id)
+{
+	struct device_node *child_np, *np = adev->dev.of_node;
+	struct device *dev = &adev->dev;
+	static const char *rev = "?";
+	struct pl172_data *pl172;
+	int ret;
+
+	if (amba_part(adev) == 0x172) {
+		if (amba_rev(adev) < ARRAY_SIZE(pl172_revisions))
+			rev = pl172_revisions[amba_rev(adev)];
+	}
+
+	dev_info(dev, "ARM PL%x revision %s\n", amba_part(adev), rev);
+
+	pl172 = devm_kzalloc(dev, sizeof(*pl172), GFP_KERNEL);
+	if (!pl172)
+		return -ENOMEM;
+
+	pl172->clk = devm_clk_get(dev, "mpmcclk");
+	if (IS_ERR(pl172->clk)) {
+		dev_err(dev, "no mpmcclk provided clock\n");
+		return PTR_ERR(pl172->clk);
+	}
+
+	ret = clk_prepare_enable(pl172->clk);
+	if (ret) {
+		dev_err(dev, "unable to mpmcclk enable clock\n");
+		return ret;
+	}
+
+	pl172->rate = clk_get_rate(pl172->clk) / MSEC_PER_SEC;
+	if (!pl172->rate) {
+		dev_err(dev, "unable to get mpmcclk clock rate\n");
+		ret = -EINVAL;
+		goto err_clk_enable;
+	}
+
+	ret = amba_request_regions(adev, NULL);
+	if (ret) {
+		dev_err(dev, "unable to request AMBA regions\n");
+		goto err_clk_enable;
+	}
+
+	pl172->base = devm_ioremap(dev, adev->res.start,
+				   resource_size(&adev->res));
+	if (!pl172->base) {
+		dev_err(dev, "ioremap failed\n");
+		ret = -ENOMEM;
+		goto err_no_ioremap;
+	}
+
+	amba_set_drvdata(adev, pl172);
+
+	/*
+	 * Loop through each child node, which represent a chip select, and
+	 * configure parameters and timing. If successful; populate devices
+	 * under that node.
+	 */
+	for_each_available_child_of_node(np, child_np) {
+		ret = pl172_parse_cs_config(adev, child_np);
+		if (ret)
+			continue;
+
+		of_platform_populate(child_np, of_default_bus_match_table,
+				     NULL, dev);
+	}
+
+	return 0;
+
+err_no_ioremap:
+	amba_release_regions(adev);
+err_clk_enable:
+	clk_disable_unprepare(pl172->clk);
+	return ret;
+}
+
+static int pl172_remove(struct amba_device *adev)
+{
+	struct pl172_data *pl172 = amba_get_drvdata(adev);
+
+	clk_disable_unprepare(pl172->clk);
+	amba_release_regions(adev);
+
+	return 0;
+}
+
+static const struct amba_id pl172_ids[] = {
+	{
+		.id	= 0x07341172,
+		.mask	= 0xffffffff,
+	},
+	{ 0, 0 },
+};
+MODULE_DEVICE_TABLE(amba, pl172_ids);
+
+static struct amba_driver pl172_driver = {
+	.drv = {
+		.name	= "memory-pl172",
+	},
+	.probe		= pl172_probe,
+	.remove		= pl172_remove,
+	.id_table	= pl172_ids,
+};
+module_amba_driver(pl172_driver);
+
+MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
+MODULE_DESCRIPTION("PL172 Memory Controller Driver");
+MODULE_LICENSE("GPL v2");