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[194.187.74.233]) by smtp.gmail.com with ESMTPSA id t17sm1396694lft.224.2021.03.04.06.41.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Mar 2021 06:41:56 -0800 (PST) From: =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= To: Srinivas Kandagatla , Rob Herring Cc: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, Florian Fainelli , Vivek Unune , bcm-kernel-feedback-list@broadcom.com, linux-kernel@vger.kernel.org, =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= Subject: [PATCH 2/2] nvmem: iomap: new driver exposing NVMEM accessible using I/O mapping Date: Thu, 4 Mar 2021 15:41:32 +0100 Message-Id: <20210304144132.24098-2-zajec5@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210304144132.24098-1-zajec5@gmail.com> References: <20210304144132.24098-1-zajec5@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org From: Rafał Miłecki This is a generic NVMEM access method used e.g. by Broadcom for their NVRAM on MIPS and Northstar devices. Signed-off-by: Rafał Miłecki --- drivers/nvmem/Kconfig | 7 +++ drivers/nvmem/Makefile | 2 + drivers/nvmem/iomap.c | 99 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 108 insertions(+) create mode 100644 drivers/nvmem/iomap.c diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig index 75d2594c16e1..3d5c5684685d 100644 --- a/drivers/nvmem/Kconfig +++ b/drivers/nvmem/Kconfig @@ -278,4 +278,11 @@ config NVMEM_RMEM This driver can also be built as a module. If so, the module will be called nvmem-rmem. + +config NVMEM_IOMAP + tristate "I/O mapped NVMEM support" + depends on HAS_IOMEM + help + This driver supports NVMEM that can be accessed using I/O mapping. + endif diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile index 5376b8e0dae5..88a3b6979c53 100644 --- a/drivers/nvmem/Makefile +++ b/drivers/nvmem/Makefile @@ -57,3 +57,5 @@ obj-$(CONFIG_SPRD_EFUSE) += nvmem_sprd_efuse.o nvmem_sprd_efuse-y := sprd-efuse.o obj-$(CONFIG_NVMEM_RMEM) += nvmem-rmem.o nvmem-rmem-y := rmem.o +obj-$(CONFIG_NVMEM_IOMAP) += nvmem_iomap.o +nvmem_iomap-y := iomap.o diff --git a/drivers/nvmem/iomap.c b/drivers/nvmem/iomap.c new file mode 100644 index 000000000000..ab6b40858a64 --- /dev/null +++ b/drivers/nvmem/iomap.c @@ -0,0 +1,99 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2021 Rafał Miłecki + */ + +#include +#include +#include +#include +#include + +struct iomap { + struct device *dev; + void __iomem *base; +}; + +static int iomap_read(void *context, unsigned int offset, void *val, + size_t bytes) +{ + struct iomap *priv = context; + u8 *src = priv->base + offset; + u8 *dst = val; + size_t tmp; + + tmp = offset % 4; + memcpy_fromio(dst, src, tmp); + dst += tmp; + src += tmp; + bytes -= tmp; + + tmp = rounddown(bytes, 4); + __ioread32_copy(dst, src, tmp / 4); + dst += tmp; + src += tmp; + bytes -= tmp; + + memcpy_fromio(dst, src, bytes); + + return 0; +} + +static int iomap_probe(struct platform_device *pdev) +{ + struct nvmem_config config = { + .name = "iomap", + .reg_read = iomap_read, + }; + struct device *dev = &pdev->dev; + struct resource *res; + struct iomap *priv; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + priv->dev = dev; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(dev, "Failed to get resource\n"); + return -ENODEV; + } + + priv->base = devm_ioremap_resource(dev, res); + if (IS_ERR(priv->base)) { + dev_err(dev, "Failed to map resource: %ld\n", PTR_ERR(priv->base)); + return PTR_ERR(priv->base); + } + + config.dev = dev; + config.priv = priv; + config.size = resource_size(res); + + return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config)); +} + +static const struct of_device_id iomap_of_match_table[] = { + { .compatible = "brcm,nvram", }, + { .compatible = "nvmem-iomap", }, + {}, +}; + +static struct platform_driver iomap_driver = { + .probe = iomap_probe, + .driver = { + .name = "nvmem_iomap", + .of_match_table = iomap_of_match_table, + }, +}; + +static int __init iomap_init(void) +{ + return platform_driver_register(&iomap_driver); +} + +subsys_initcall_sync(iomap_init); + +MODULE_AUTHOR("Rafał Miłecki"); +MODULE_LICENSE("GPL v2"); +MODULE_DEVICE_TABLE(of, iomap_of_match_table);