diff options
Diffstat (limited to 'drivers/memory/samsung/exynos-srom.c')
| -rw-r--r-- | drivers/memory/samsung/exynos-srom.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/drivers/memory/samsung/exynos-srom.c b/drivers/memory/samsung/exynos-srom.c new file mode 100644 index 000000000..e73dd330a --- /dev/null +++ b/drivers/memory/samsung/exynos-srom.c @@ -0,0 +1,212 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Copyright (c) 2015 Samsung Electronics Co., Ltd. +// http://www.samsung.com/ +// +// Exynos - SROM Controller support +// Author: Pankaj Dubey <pankaj.dubey@samsung.com> + +#include <linux/io.h> +#include <linux/init.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/slab.h> + +#include "exynos-srom.h" + +static const unsigned long exynos_srom_offsets[] = { + /* SROM side */ + EXYNOS_SROM_BW, + EXYNOS_SROM_BC0, + EXYNOS_SROM_BC1, + EXYNOS_SROM_BC2, + EXYNOS_SROM_BC3, +}; + +/** + * struct exynos_srom_reg_dump: register dump of SROM Controller registers. + * @offset: srom register offset from the controller base address. + * @value: the value of register under the offset. + */ +struct exynos_srom_reg_dump { + u32 offset; + u32 value; +}; + +/** + * struct exynos_srom: platform data for exynos srom controller driver. + * @dev: platform device pointer + * @reg_base: srom base address + * @reg_offset: exynos_srom_reg_dump pointer to hold offset and its value. + */ +struct exynos_srom { + struct device *dev; + void __iomem *reg_base; + struct exynos_srom_reg_dump *reg_offset; +}; + +static struct exynos_srom_reg_dump * +exynos_srom_alloc_reg_dump(const unsigned long *rdump, + unsigned long nr_rdump) +{ + struct exynos_srom_reg_dump *rd; + unsigned int i; + + rd = kcalloc(nr_rdump, sizeof(*rd), GFP_KERNEL); + if (!rd) + return NULL; + + for (i = 0; i < nr_rdump; ++i) + rd[i].offset = rdump[i]; + + return rd; +} + +static int exynos_srom_configure_bank(struct exynos_srom *srom, + struct device_node *np) +{ + u32 bank, width, pmc = 0; + u32 timing[6]; + u32 cs, bw; + + if (of_property_read_u32(np, "reg", &bank)) + return -EINVAL; + if (of_property_read_u32(np, "reg-io-width", &width)) + width = 1; + if (of_property_read_bool(np, "samsung,srom-page-mode")) + pmc = 1 << EXYNOS_SROM_BCX__PMC__SHIFT; + if (of_property_read_u32_array(np, "samsung,srom-timing", timing, + ARRAY_SIZE(timing))) + return -EINVAL; + + bank *= 4; /* Convert bank into shift/offset */ + + cs = 1 << EXYNOS_SROM_BW__BYTEENABLE__SHIFT; + if (width == 2) + cs |= 1 << EXYNOS_SROM_BW__DATAWIDTH__SHIFT; + + bw = readl_relaxed(srom->reg_base + EXYNOS_SROM_BW); + bw = (bw & ~(EXYNOS_SROM_BW__CS_MASK << bank)) | (cs << bank); + writel_relaxed(bw, srom->reg_base + EXYNOS_SROM_BW); + + writel_relaxed(pmc | (timing[0] << EXYNOS_SROM_BCX__TACP__SHIFT) | + (timing[1] << EXYNOS_SROM_BCX__TCAH__SHIFT) | + (timing[2] << EXYNOS_SROM_BCX__TCOH__SHIFT) | + (timing[3] << EXYNOS_SROM_BCX__TACC__SHIFT) | + (timing[4] << EXYNOS_SROM_BCX__TCOS__SHIFT) | + (timing[5] << EXYNOS_SROM_BCX__TACS__SHIFT), + srom->reg_base + EXYNOS_SROM_BC0 + bank); + + return 0; +} + +static int exynos_srom_probe(struct platform_device *pdev) +{ + struct device_node *np, *child; + struct exynos_srom *srom; + struct device *dev = &pdev->dev; + bool bad_bank_config = false; + + np = dev->of_node; + if (!np) { + dev_err(&pdev->dev, "could not find device info\n"); + return -EINVAL; + } + + srom = devm_kzalloc(&pdev->dev, + sizeof(struct exynos_srom), GFP_KERNEL); + if (!srom) + return -ENOMEM; + + srom->dev = dev; + srom->reg_base = of_iomap(np, 0); + if (!srom->reg_base) { + dev_err(&pdev->dev, "iomap of exynos srom controller failed\n"); + return -ENOMEM; + } + + platform_set_drvdata(pdev, srom); + + srom->reg_offset = exynos_srom_alloc_reg_dump(exynos_srom_offsets, + ARRAY_SIZE(exynos_srom_offsets)); + if (!srom->reg_offset) { + iounmap(srom->reg_base); + return -ENOMEM; + } + + for_each_child_of_node(np, child) { + if (exynos_srom_configure_bank(srom, child)) { + dev_err(dev, + "Could not decode bank configuration for %pOFn\n", + child); + bad_bank_config = true; + } + } + + /* + * If any bank failed to configure, we still provide suspend/resume, + * but do not probe child devices + */ + if (bad_bank_config) + return 0; + + return of_platform_populate(np, NULL, NULL, dev); +} + +#ifdef CONFIG_PM_SLEEP +static void exynos_srom_save(void __iomem *base, + struct exynos_srom_reg_dump *rd, + unsigned int num_regs) +{ + for (; num_regs > 0; --num_regs, ++rd) + rd->value = readl(base + rd->offset); +} + +static void exynos_srom_restore(void __iomem *base, + const struct exynos_srom_reg_dump *rd, + unsigned int num_regs) +{ + for (; num_regs > 0; --num_regs, ++rd) + writel(rd->value, base + rd->offset); +} + +static int exynos_srom_suspend(struct device *dev) +{ + struct exynos_srom *srom = dev_get_drvdata(dev); + + exynos_srom_save(srom->reg_base, srom->reg_offset, + ARRAY_SIZE(exynos_srom_offsets)); + return 0; +} + +static int exynos_srom_resume(struct device *dev) +{ + struct exynos_srom *srom = dev_get_drvdata(dev); + + exynos_srom_restore(srom->reg_base, srom->reg_offset, + ARRAY_SIZE(exynos_srom_offsets)); + return 0; +} +#endif + +static const struct of_device_id of_exynos_srom_ids[] = { + { + .compatible = "samsung,exynos4210-srom", + }, + {}, +}; + +static SIMPLE_DEV_PM_OPS(exynos_srom_pm_ops, exynos_srom_suspend, exynos_srom_resume); + +static struct platform_driver exynos_srom_driver = { + .probe = exynos_srom_probe, + .driver = { + .name = "exynos-srom", + .of_match_table = of_exynos_srom_ids, + .pm = &exynos_srom_pm_ops, + .suppress_bind_attrs = true, + }, +}; +builtin_platform_driver(exynos_srom_driver); |