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![Zhang Changzhong](/assets/img/avatar_default.png)
platform_get_resource() may fail and return NULL, so we should
better check it's return value to avoid a NULL pointer dereference
a bit later in the code.
This is detected by Coccinelle semantic patch.
Fixes: 911a888297
("memory: jz4780-nemc: driver for the NEMC on JZ4780 SoCs")
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Acked-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/1607070717-32880-1-git-send-email-zhangchangzhong@huawei.com
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
423 lines
10 KiB
C
423 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* JZ4780 NAND/external memory controller (NEMC)
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*
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* Copyright (c) 2015 Imagination Technologies
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* Author: Alex Smith <alex@alex-smith.me.uk>
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*/
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#include <linux/clk.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/math64.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_device.h>
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#include <linux/of_platform.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/jz4780-nemc.h>
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#define NEMC_SMCRn(n) (0x14 + (((n) - 1) * 4))
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#define NEMC_NFCSR 0x50
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#define NEMC_REG_LEN 0x54
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#define NEMC_SMCR_SMT BIT(0)
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#define NEMC_SMCR_BW_SHIFT 6
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#define NEMC_SMCR_BW_MASK (0x3 << NEMC_SMCR_BW_SHIFT)
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#define NEMC_SMCR_BW_8 (0 << 6)
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#define NEMC_SMCR_TAS_SHIFT 8
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#define NEMC_SMCR_TAS_MASK (0xf << NEMC_SMCR_TAS_SHIFT)
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#define NEMC_SMCR_TAH_SHIFT 12
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#define NEMC_SMCR_TAH_MASK (0xf << NEMC_SMCR_TAH_SHIFT)
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#define NEMC_SMCR_TBP_SHIFT 16
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#define NEMC_SMCR_TBP_MASK (0xf << NEMC_SMCR_TBP_SHIFT)
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#define NEMC_SMCR_TAW_SHIFT 20
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#define NEMC_SMCR_TAW_MASK (0xf << NEMC_SMCR_TAW_SHIFT)
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#define NEMC_SMCR_TSTRV_SHIFT 24
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#define NEMC_SMCR_TSTRV_MASK (0x3f << NEMC_SMCR_TSTRV_SHIFT)
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#define NEMC_NFCSR_NFEn(n) BIT(((n) - 1) << 1)
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#define NEMC_NFCSR_NFCEn(n) BIT((((n) - 1) << 1) + 1)
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#define NEMC_NFCSR_TNFEn(n) BIT(16 + (n) - 1)
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struct jz_soc_info {
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u8 tas_tah_cycles_max;
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};
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struct jz4780_nemc {
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spinlock_t lock;
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struct device *dev;
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const struct jz_soc_info *soc_info;
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void __iomem *base;
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struct clk *clk;
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uint32_t clk_period;
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unsigned long banks_present;
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};
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/**
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* jz4780_nemc_num_banks() - count the number of banks referenced by a device
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* @dev: device to count banks for, must be a child of the NEMC.
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*
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* Return: The number of unique NEMC banks referred to by the specified NEMC
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* child device. Unique here means that a device that references the same bank
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* multiple times in its "reg" property will only count once.
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*/
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unsigned int jz4780_nemc_num_banks(struct device *dev)
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{
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const __be32 *prop;
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unsigned int bank, count = 0;
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unsigned long referenced = 0;
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int i = 0;
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while ((prop = of_get_address(dev->of_node, i++, NULL, NULL))) {
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bank = of_read_number(prop, 1);
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if (!(referenced & BIT(bank))) {
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referenced |= BIT(bank);
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count++;
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}
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}
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return count;
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}
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EXPORT_SYMBOL(jz4780_nemc_num_banks);
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/**
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* jz4780_nemc_set_type() - set the type of device connected to a bank
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* @dev: child device of the NEMC.
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* @bank: bank number to configure.
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* @type: type of device connected to the bank.
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*/
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void jz4780_nemc_set_type(struct device *dev, unsigned int bank,
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enum jz4780_nemc_bank_type type)
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{
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struct jz4780_nemc *nemc = dev_get_drvdata(dev->parent);
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uint32_t nfcsr;
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nfcsr = readl(nemc->base + NEMC_NFCSR);
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/* TODO: Support toggle NAND devices. */
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switch (type) {
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case JZ4780_NEMC_BANK_SRAM:
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nfcsr &= ~(NEMC_NFCSR_TNFEn(bank) | NEMC_NFCSR_NFEn(bank));
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break;
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case JZ4780_NEMC_BANK_NAND:
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nfcsr &= ~NEMC_NFCSR_TNFEn(bank);
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nfcsr |= NEMC_NFCSR_NFEn(bank);
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break;
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}
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writel(nfcsr, nemc->base + NEMC_NFCSR);
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}
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EXPORT_SYMBOL(jz4780_nemc_set_type);
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/**
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* jz4780_nemc_assert() - (de-)assert a NAND device's chip enable pin
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* @dev: child device of the NEMC.
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* @bank: bank number of device.
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* @assert: whether the chip enable pin should be asserted.
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*
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* (De-)asserts the chip enable pin for the NAND device connected to the
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* specified bank.
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*/
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void jz4780_nemc_assert(struct device *dev, unsigned int bank, bool assert)
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{
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struct jz4780_nemc *nemc = dev_get_drvdata(dev->parent);
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uint32_t nfcsr;
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nfcsr = readl(nemc->base + NEMC_NFCSR);
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if (assert)
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nfcsr |= NEMC_NFCSR_NFCEn(bank);
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else
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nfcsr &= ~NEMC_NFCSR_NFCEn(bank);
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writel(nfcsr, nemc->base + NEMC_NFCSR);
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}
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EXPORT_SYMBOL(jz4780_nemc_assert);
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static uint32_t jz4780_nemc_clk_period(struct jz4780_nemc *nemc)
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{
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unsigned long rate;
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rate = clk_get_rate(nemc->clk);
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if (!rate)
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return 0;
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/* Return in picoseconds. */
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return div64_ul(1000000000000ull, rate);
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}
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static uint32_t jz4780_nemc_ns_to_cycles(struct jz4780_nemc *nemc, uint32_t ns)
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{
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return ((ns * 1000) + nemc->clk_period - 1) / nemc->clk_period;
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}
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static bool jz4780_nemc_configure_bank(struct jz4780_nemc *nemc,
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unsigned int bank,
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struct device_node *node)
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{
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uint32_t smcr, val, cycles;
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/*
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* Conversion of tBP and tAW cycle counts to values supported by the
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* hardware (round up to the next supported value).
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*/
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static const u8 convert_tBP_tAW[] = {
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
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/* 11 - 12 -> 12 cycles */
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11, 11,
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/* 13 - 15 -> 15 cycles */
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12, 12, 12,
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/* 16 - 20 -> 20 cycles */
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13, 13, 13, 13, 13,
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/* 21 - 25 -> 25 cycles */
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14, 14, 14, 14, 14,
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/* 26 - 31 -> 31 cycles */
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15, 15, 15, 15, 15, 15
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};
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smcr = readl(nemc->base + NEMC_SMCRn(bank));
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smcr &= ~NEMC_SMCR_SMT;
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if (!of_property_read_u32(node, "ingenic,nemc-bus-width", &val)) {
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smcr &= ~NEMC_SMCR_BW_MASK;
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switch (val) {
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case 8:
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smcr |= NEMC_SMCR_BW_8;
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break;
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default:
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/*
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* Earlier SoCs support a 16 bit bus width (the 4780
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* does not), until those are properly supported, error.
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*/
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dev_err(nemc->dev, "unsupported bus width: %u\n", val);
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return false;
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}
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}
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if (of_property_read_u32(node, "ingenic,nemc-tAS", &val) == 0) {
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smcr &= ~NEMC_SMCR_TAS_MASK;
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cycles = jz4780_nemc_ns_to_cycles(nemc, val);
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if (cycles > nemc->soc_info->tas_tah_cycles_max) {
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dev_err(nemc->dev, "tAS %u is too high (%u cycles)\n",
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val, cycles);
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return false;
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}
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smcr |= cycles << NEMC_SMCR_TAS_SHIFT;
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}
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if (of_property_read_u32(node, "ingenic,nemc-tAH", &val) == 0) {
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smcr &= ~NEMC_SMCR_TAH_MASK;
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cycles = jz4780_nemc_ns_to_cycles(nemc, val);
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if (cycles > nemc->soc_info->tas_tah_cycles_max) {
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dev_err(nemc->dev, "tAH %u is too high (%u cycles)\n",
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val, cycles);
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return false;
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}
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smcr |= cycles << NEMC_SMCR_TAH_SHIFT;
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}
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if (of_property_read_u32(node, "ingenic,nemc-tBP", &val) == 0) {
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smcr &= ~NEMC_SMCR_TBP_MASK;
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cycles = jz4780_nemc_ns_to_cycles(nemc, val);
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if (cycles > 31) {
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dev_err(nemc->dev, "tBP %u is too high (%u cycles)\n",
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val, cycles);
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return false;
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}
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smcr |= convert_tBP_tAW[cycles] << NEMC_SMCR_TBP_SHIFT;
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}
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if (of_property_read_u32(node, "ingenic,nemc-tAW", &val) == 0) {
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smcr &= ~NEMC_SMCR_TAW_MASK;
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cycles = jz4780_nemc_ns_to_cycles(nemc, val);
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if (cycles > 31) {
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dev_err(nemc->dev, "tAW %u is too high (%u cycles)\n",
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val, cycles);
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return false;
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}
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smcr |= convert_tBP_tAW[cycles] << NEMC_SMCR_TAW_SHIFT;
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}
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if (of_property_read_u32(node, "ingenic,nemc-tSTRV", &val) == 0) {
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smcr &= ~NEMC_SMCR_TSTRV_MASK;
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cycles = jz4780_nemc_ns_to_cycles(nemc, val);
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if (cycles > 63) {
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dev_err(nemc->dev, "tSTRV %u is too high (%u cycles)\n",
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val, cycles);
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return false;
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}
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smcr |= cycles << NEMC_SMCR_TSTRV_SHIFT;
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}
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writel(smcr, nemc->base + NEMC_SMCRn(bank));
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return true;
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}
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static int jz4780_nemc_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct jz4780_nemc *nemc;
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struct resource *res;
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struct device_node *child;
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const __be32 *prop;
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unsigned int bank;
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unsigned long referenced;
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int i, ret;
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nemc = devm_kzalloc(dev, sizeof(*nemc), GFP_KERNEL);
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if (!nemc)
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return -ENOMEM;
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nemc->soc_info = device_get_match_data(dev);
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if (!nemc->soc_info)
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return -EINVAL;
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spin_lock_init(&nemc->lock);
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nemc->dev = dev;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res)
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return -EINVAL;
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/*
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* The driver currently only uses the registers up to offset
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* NEMC_REG_LEN. Since the EFUSE registers are in the middle of the
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* NEMC registers, we only request the registers we will use for now;
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* that way the EFUSE driver can probe too.
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*/
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if (!devm_request_mem_region(dev, res->start, NEMC_REG_LEN, dev_name(dev))) {
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dev_err(dev, "unable to request I/O memory region\n");
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return -EBUSY;
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}
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nemc->base = devm_ioremap(dev, res->start, NEMC_REG_LEN);
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if (!nemc->base) {
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dev_err(dev, "failed to get I/O memory\n");
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return -ENOMEM;
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}
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writel(0, nemc->base + NEMC_NFCSR);
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nemc->clk = devm_clk_get(dev, NULL);
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if (IS_ERR(nemc->clk)) {
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dev_err(dev, "failed to get clock\n");
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return PTR_ERR(nemc->clk);
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}
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ret = clk_prepare_enable(nemc->clk);
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if (ret) {
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dev_err(dev, "failed to enable clock: %d\n", ret);
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return ret;
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}
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nemc->clk_period = jz4780_nemc_clk_period(nemc);
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if (!nemc->clk_period) {
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dev_err(dev, "failed to calculate clock period\n");
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clk_disable_unprepare(nemc->clk);
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return -EINVAL;
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}
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/*
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* Iterate over child devices, check that they do not conflict with
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* each other, and register child devices for them. If a child device
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* has invalid properties, it is ignored and no platform device is
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* registered for it.
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*/
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for_each_child_of_node(nemc->dev->of_node, child) {
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referenced = 0;
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i = 0;
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while ((prop = of_get_address(child, i++, NULL, NULL))) {
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bank = of_read_number(prop, 1);
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if (bank < 1 || bank >= JZ4780_NEMC_NUM_BANKS) {
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dev_err(nemc->dev,
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"%pOF requests invalid bank %u\n",
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child, bank);
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/* Will continue the outer loop below. */
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referenced = 0;
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break;
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}
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referenced |= BIT(bank);
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}
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if (!referenced) {
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dev_err(nemc->dev, "%pOF has no addresses\n",
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child);
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continue;
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} else if (nemc->banks_present & referenced) {
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dev_err(nemc->dev, "%pOF conflicts with another node\n",
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child);
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continue;
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}
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/* Configure bank parameters. */
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for_each_set_bit(bank, &referenced, JZ4780_NEMC_NUM_BANKS) {
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if (!jz4780_nemc_configure_bank(nemc, bank, child)) {
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referenced = 0;
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break;
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}
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}
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if (referenced) {
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if (of_platform_device_create(child, NULL, nemc->dev))
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nemc->banks_present |= referenced;
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}
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}
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platform_set_drvdata(pdev, nemc);
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dev_info(dev, "JZ4780 NEMC initialised\n");
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return 0;
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}
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static int jz4780_nemc_remove(struct platform_device *pdev)
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{
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struct jz4780_nemc *nemc = platform_get_drvdata(pdev);
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clk_disable_unprepare(nemc->clk);
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return 0;
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}
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static const struct jz_soc_info jz4740_soc_info = {
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.tas_tah_cycles_max = 7,
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};
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static const struct jz_soc_info jz4780_soc_info = {
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.tas_tah_cycles_max = 15,
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};
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static const struct of_device_id jz4780_nemc_dt_match[] = {
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{ .compatible = "ingenic,jz4740-nemc", .data = &jz4740_soc_info, },
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{ .compatible = "ingenic,jz4780-nemc", .data = &jz4780_soc_info, },
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{},
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};
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static struct platform_driver jz4780_nemc_driver = {
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.probe = jz4780_nemc_probe,
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.remove = jz4780_nemc_remove,
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.driver = {
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.name = "jz4780-nemc",
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.of_match_table = of_match_ptr(jz4780_nemc_dt_match),
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},
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};
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static int __init jz4780_nemc_init(void)
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{
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return platform_driver_register(&jz4780_nemc_driver);
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}
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subsys_initcall(jz4780_nemc_init);
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