1 files changed, 391 insertions, 0 deletions
diff --git a/drivers/memory/jz4780-nemc.c b/drivers/memory/jz4780-nemc.c
new file mode 100644
index 000000000000..919d1925acb9
--- /dev/null
+++ b/drivers/memory/jz4780-nemc.c
@@ -0,0 +1,391 @@
+/*
+ * JZ4780 NAND/external memory controller (NEMC)
+ *
+ * Copyright (c) 2015 Imagination Technologies
+ * Author: Alex Smith <alex@alex-smith.me.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/init.h>
+#include <linux/math64.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include <linux/jz4780-nemc.h>
+
+#define NEMC_SMCRn(n)		(0x14 + (((n) - 1) * 4))
+#define NEMC_NFCSR		0x50
+
+#define NEMC_SMCR_SMT		BIT(0)
+#define NEMC_SMCR_BW_SHIFT	6
+#define NEMC_SMCR_BW_MASK	(0x3 << NEMC_SMCR_BW_SHIFT)
+#define NEMC_SMCR_BW_8		(0 << 6)
+#define NEMC_SMCR_TAS_SHIFT	8
+#define NEMC_SMCR_TAS_MASK	(0xf << NEMC_SMCR_TAS_SHIFT)
+#define NEMC_SMCR_TAH_SHIFT	12
+#define NEMC_SMCR_TAH_MASK	(0xf << NEMC_SMCR_TAH_SHIFT)
+#define NEMC_SMCR_TBP_SHIFT	16
+#define NEMC_SMCR_TBP_MASK	(0xf << NEMC_SMCR_TBP_SHIFT)
+#define NEMC_SMCR_TAW_SHIFT	20
+#define NEMC_SMCR_TAW_MASK	(0xf << NEMC_SMCR_TAW_SHIFT)
+#define NEMC_SMCR_TSTRV_SHIFT	24
+#define NEMC_SMCR_TSTRV_MASK	(0x3f << NEMC_SMCR_TSTRV_SHIFT)
+
+#define NEMC_NFCSR_NFEn(n)	BIT(((n) - 1) << 1)
+#define NEMC_NFCSR_NFCEn(n)	BIT((((n) - 1) << 1) + 1)
+#define NEMC_NFCSR_TNFEn(n)	BIT(16 + (n) - 1)
+
+struct jz4780_nemc {
+	spinlock_t lock;
+	struct device *dev;
+	void __iomem *base;
+	struct clk *clk;
+	uint32_t clk_period;
+	unsigned long banks_present;
+};
+
+/**
+ * jz4780_nemc_num_banks() - count the number of banks referenced by a device
+ * @dev: device to count banks for, must be a child of the NEMC.
+ *
+ * Return: The number of unique NEMC banks referred to by the specified NEMC
+ * child device. Unique here means that a device that references the same bank
+ * multiple times in the its "reg" property will only count once.
+ */
+unsigned int jz4780_nemc_num_banks(struct device *dev)
+{
+	const __be32 *prop;
+	unsigned int bank, count = 0;
+	unsigned long referenced = 0;
+	int i = 0;
+
+	while ((prop = of_get_address(dev->of_node, i++, NULL, NULL))) {
+		bank = of_read_number(prop, 1);
+		if (!(referenced & BIT(bank))) {
+			referenced |= BIT(bank);
+			count++;
+		}
+	}
+
+	return count;
+}
+EXPORT_SYMBOL(jz4780_nemc_num_banks);
+
+/**
+ * jz4780_nemc_set_type() - set the type of device connected to a bank
+ * @dev: child device of the NEMC.
+ * @bank: bank number to configure.
+ * @type: type of device connected to the bank.
+ */
+void jz4780_nemc_set_type(struct device *dev, unsigned int bank,
+			  enum jz4780_nemc_bank_type type)
+{
+	struct jz4780_nemc *nemc = dev_get_drvdata(dev->parent);
+	uint32_t nfcsr;
+
+	nfcsr = readl(nemc->base + NEMC_NFCSR);
+
+	/* TODO: Support toggle NAND devices. */
+	switch (type) {
+	case JZ4780_NEMC_BANK_SRAM:
+		nfcsr &= ~(NEMC_NFCSR_TNFEn(bank) | NEMC_NFCSR_NFEn(bank));
+		break;
+	case JZ4780_NEMC_BANK_NAND:
+		nfcsr &= ~NEMC_NFCSR_TNFEn(bank);
+		nfcsr |= NEMC_NFCSR_NFEn(bank);
+		break;
+	}
+
+	writel(nfcsr, nemc->base + NEMC_NFCSR);
+}
+EXPORT_SYMBOL(jz4780_nemc_set_type);
+
+/**
+ * jz4780_nemc_assert() - (de-)assert a NAND device's chip enable pin
+ * @dev: child device of the NEMC.
+ * @bank: bank number of device.
+ * @assert: whether the chip enable pin should be asserted.
+ *
+ * (De-)asserts the chip enable pin for the NAND device connected to the
+ * specified bank.
+ */
+void jz4780_nemc_assert(struct device *dev, unsigned int bank, bool assert)
+{
+	struct jz4780_nemc *nemc = dev_get_drvdata(dev->parent);
+	uint32_t nfcsr;
+
+	nfcsr = readl(nemc->base + NEMC_NFCSR);
+
+	if (assert)
+		nfcsr |= NEMC_NFCSR_NFCEn(bank);
+	else
+		nfcsr &= ~NEMC_NFCSR_NFCEn(bank);
+
+	writel(nfcsr, nemc->base + NEMC_NFCSR);
+}
+EXPORT_SYMBOL(jz4780_nemc_assert);
+
+static uint32_t jz4780_nemc_clk_period(struct jz4780_nemc *nemc)
+{
+	unsigned long rate;
+
+	rate = clk_get_rate(nemc->clk);
+	if (!rate)
+		return 0;
+
+	/* Return in picoseconds. */
+	return div64_ul(1000000000000ull, rate);
+}
+
+static uint32_t jz4780_nemc_ns_to_cycles(struct jz4780_nemc *nemc, uint32_t ns)
+{
+	return ((ns * 1000) + nemc->clk_period - 1) / nemc->clk_period;
+}
+
+static bool jz4780_nemc_configure_bank(struct jz4780_nemc *nemc,
+				       unsigned int bank,
+				       struct device_node *node)
+{
+	uint32_t smcr, val, cycles;
+
+	/*
+	 * Conversion of tBP and tAW cycle counts to values supported by the
+	 * hardware (round up to the next supported value).
+	 */
+	static const uint32_t convert_tBP_tAW[] = {
+		0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
+
+		/* 11 - 12 -> 12 cycles */
+		11, 11,
+
+		/* 13 - 15 -> 15 cycles */
+		12, 12, 12,
+
+		/* 16 - 20 -> 20 cycles */
+		13, 13, 13, 13, 13,
+
+		/* 21 - 25 -> 25 cycles */
+		14, 14, 14, 14, 14,
+
+		/* 26 - 31 -> 31 cycles */
+		15, 15, 15, 15, 15, 15
+	};
+
+	smcr = readl(nemc->base + NEMC_SMCRn(bank));
+	smcr &= ~NEMC_SMCR_SMT;
+
+	if (!of_property_read_u32(node, "ingenic,nemc-bus-width", &val)) {
+		smcr &= ~NEMC_SMCR_BW_MASK;
+		switch (val) {
+		case 8:
+			smcr |= NEMC_SMCR_BW_8;
+			break;
+		default:
+			/*
+			 * Earlier SoCs support a 16 bit bus width (the 4780
+			 * does not), until those are properly supported, error.
+			 */
+			dev_err(nemc->dev, "unsupported bus width: %u\n", val);
+			return false;
+		}
+	}
+
+	if (of_property_read_u32(node, "ingenic,nemc-tAS", &val) == 0) {
+		smcr &= ~NEMC_SMCR_TAS_MASK;
+		cycles = jz4780_nemc_ns_to_cycles(nemc, val);
+		if (cycles > 15) {
+			dev_err(nemc->dev, "tAS %u is too high (%u cycles)\n",
+				val, cycles);
+			return false;
+		}
+
+		smcr |= cycles << NEMC_SMCR_TAS_SHIFT;
+	}
+
+	if (of_property_read_u32(node, "ingenic,nemc-tAH", &val) == 0) {
+		smcr &= ~NEMC_SMCR_TAH_MASK;
+		cycles = jz4780_nemc_ns_to_cycles(nemc, val);
+		if (cycles > 15) {
+			dev_err(nemc->dev, "tAH %u is too high (%u cycles)\n",
+				val, cycles);
+			return false;
+		}
+
+		smcr |= cycles << NEMC_SMCR_TAH_SHIFT;
+	}
+
+	if (of_property_read_u32(node, "ingenic,nemc-tBP", &val) == 0) {
+		smcr &= ~NEMC_SMCR_TBP_MASK;
+		cycles = jz4780_nemc_ns_to_cycles(nemc, val);
+		if (cycles > 31) {
+			dev_err(nemc->dev, "tBP %u is too high (%u cycles)\n",
+				val, cycles);
+			return false;
+		}
+
+		smcr |= convert_tBP_tAW[cycles] << NEMC_SMCR_TBP_SHIFT;
+	}
+
+	if (of_property_read_u32(node, "ingenic,nemc-tAW", &val) == 0) {
+		smcr &= ~NEMC_SMCR_TAW_MASK;
+		cycles = jz4780_nemc_ns_to_cycles(nemc, val);
+		if (cycles > 31) {
+			dev_err(nemc->dev, "tAW %u is too high (%u cycles)\n",
+				val, cycles);
+			return false;
+		}
+
+		smcr |= convert_tBP_tAW[cycles] << NEMC_SMCR_TAW_SHIFT;
+	}
+
+	if (of_property_read_u32(node, "ingenic,nemc-tSTRV", &val) == 0) {
+		smcr &= ~NEMC_SMCR_TSTRV_MASK;
+		cycles = jz4780_nemc_ns_to_cycles(nemc, val);
+		if (cycles > 63) {
+			dev_err(nemc->dev, "tSTRV %u is too high (%u cycles)\n",
+				val, cycles);
+			return false;
+		}
+
+		smcr |= cycles << NEMC_SMCR_TSTRV_SHIFT;
+	}
+
+	writel(smcr, nemc->base + NEMC_SMCRn(bank));
+	return true;
+}
+
+static int jz4780_nemc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct jz4780_nemc *nemc;
+	struct resource *res;
+	struct device_node *child;
+	const __be32 *prop;
+	unsigned int bank;
+	unsigned long referenced;
+	int i, ret;
+
+	nemc = devm_kzalloc(dev, sizeof(*nemc), GFP_KERNEL);
+	if (!nemc)
+		return -ENOMEM;
+
+	spin_lock_init(&nemc->lock);
+	nemc->dev = dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	nemc->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(nemc->base)) {
+		dev_err(dev, "failed to get I/O memory\n");
+		return PTR_ERR(nemc->base);
+	}
+
+	writel(0, nemc->base + NEMC_NFCSR);
+
+	nemc->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(nemc->clk)) {
+		dev_err(dev, "failed to get clock\n");
+		return PTR_ERR(nemc->clk);
+	}
+
+	ret = clk_prepare_enable(nemc->clk);
+	if (ret) {
+		dev_err(dev, "failed to enable clock: %d\n", ret);
+		return ret;
+	}
+
+	nemc->clk_period = jz4780_nemc_clk_period(nemc);
+	if (!nemc->clk_period) {
+		dev_err(dev, "failed to calculate clock period\n");
+		clk_disable_unprepare(nemc->clk);
+		return -EINVAL;
+	}
+
+	/*
+	 * Iterate over child devices, check that they do not conflict with
+	 * each other, and register child devices for them. If a child device
+	 * has invalid properties, it is ignored and no platform device is
+	 * registered for it.
+	 */
+	for_each_child_of_node(nemc->dev->of_node, child) {
+		referenced = 0;
+		i = 0;
+		while ((prop = of_get_address(child, i++, NULL, NULL))) {
+			bank = of_read_number(prop, 1);
+			if (bank < 1 || bank >= JZ4780_NEMC_NUM_BANKS) {
+				dev_err(nemc->dev,
+					"%s requests invalid bank %u\n",
+					child->full_name, bank);
+
+				/* Will continue the outer loop below. */
+				referenced = 0;
+				break;
+			}
+
+			referenced |= BIT(bank);
+		}
+
+		if (!referenced) {
+			dev_err(nemc->dev, "%s has no addresses\n",
+				child->full_name);
+			continue;
+		} else if (nemc->banks_present & referenced) {
+			dev_err(nemc->dev, "%s conflicts with another node\n",
+				child->full_name);
+			continue;
+		}
+
+		/* Configure bank parameters. */
+		for_each_set_bit(bank, &referenced, JZ4780_NEMC_NUM_BANKS) {
+			if (!jz4780_nemc_configure_bank(nemc, bank, child)) {
+				referenced = 0;
+				break;
+			}
+		}
+
+		if (referenced) {
+			if (of_platform_device_create(child, NULL, nemc->dev))
+				nemc->banks_present |= referenced;
+		}
+	}
+
+	platform_set_drvdata(pdev, nemc);
+	dev_info(dev, "JZ4780 NEMC initialised\n");
+	return 0;
+}
+
+static int jz4780_nemc_remove(struct platform_device *pdev)
+{
+	struct jz4780_nemc *nemc = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(nemc->clk);
+	return 0;
+}
+
+static const struct of_device_id jz4780_nemc_dt_match[] = {
+	{ .compatible = "ingenic,jz4780-nemc" },
+	{},
+};
+
+static struct platform_driver jz4780_nemc_driver = {
+	.probe		= jz4780_nemc_probe,
+	.remove		= jz4780_nemc_remove,
+	.driver	= {
+		.name	= "jz4780-nemc",
+		.of_match_table = of_match_ptr(jz4780_nemc_dt_match),
+	},
+};
+
+static int __init jz4780_nemc_init(void)
+{
+	return platform_driver_register(&jz4780_nemc_driver);
+}
+subsys_initcall(jz4780_nemc_init);