diff options
Diffstat (limited to 'drivers/memory/jz4780-nemc.c')
| -rw-r--r-- | drivers/memory/jz4780-nemc.c | 391 |
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); |