From: PrasannaKumar Muralidharan prasannatsmkumar@gmail.com
This patch brings support for the JZ4780 efuse. Currently it only exposes a read only access to the entire 8K bits efuse memory and nvmem cells.
Tested-by: Mathieu Malaterre malat@debian.org Signed-off-by: PrasannaKumar Muralidharan prasannatsmkumar@gmail.com Signed-off-by: Mathieu Malaterre malat@debian.org Signed-off-by: H. Nikolaus Schaller hns@goldelico.com (Signed-off-by: Paul Cercueil paul@crapouillou.net) --- drivers/nvmem/Kconfig | 10 ++ drivers/nvmem/Makefile | 2 + drivers/nvmem/jz4780-efuse.c | 249 +++++++++++++++++++++++++++++++++++ 3 files changed, 261 insertions(+) create mode 100644 drivers/nvmem/jz4780-efuse.c
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig index 35efab1ba8d9..10f8e08f5e31 100644 --- a/drivers/nvmem/Kconfig +++ b/drivers/nvmem/Kconfig @@ -55,6 +55,16 @@ config NVMEM_IMX_OCOTP_SCU This is a driver for the SCU On-Chip OTP Controller (OCOTP) available on i.MX8 SoCs.
+config JZ4780_EFUSE + tristate "JZ4780 EFUSE Memory Support" + depends on MACH_JZ4780 || COMPILE_TEST + depends on HAS_IOMEM + help + Say Y here to include support for JZ4780 efuse memory found on + all JZ4780 SoC based devices. + To compile this driver as a module, choose M here: the module + will be called nvmem_jz4780_efuse. + config NVMEM_LPC18XX_EEPROM tristate "NXP LPC18XX EEPROM Memory Support" depends on ARCH_LPC18XX || COMPILE_TEST diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile index 6b466cd1427b..65a268d17807 100644 --- a/drivers/nvmem/Makefile +++ b/drivers/nvmem/Makefile @@ -18,6 +18,8 @@ obj-$(CONFIG_NVMEM_IMX_OCOTP) += nvmem-imx-ocotp.o nvmem-imx-ocotp-y := imx-ocotp.o obj-$(CONFIG_NVMEM_IMX_OCOTP_SCU) += nvmem-imx-ocotp-scu.o nvmem-imx-ocotp-scu-y := imx-ocotp-scu.o +obj-$(CONFIG_JZ4780_EFUSE) += nvmem_jz4780_efuse.o +nvmem_jz4780_efuse-y := jz4780-efuse.o obj-$(CONFIG_NVMEM_LPC18XX_EEPROM) += nvmem_lpc18xx_eeprom.o nvmem_lpc18xx_eeprom-y := lpc18xx_eeprom.o obj-$(CONFIG_NVMEM_LPC18XX_OTP) += nvmem_lpc18xx_otp.o diff --git a/drivers/nvmem/jz4780-efuse.c b/drivers/nvmem/jz4780-efuse.c new file mode 100644 index 000000000000..ac03e1900ef9 --- /dev/null +++ b/drivers/nvmem/jz4780-efuse.c @@ -0,0 +1,249 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * JZ4780 EFUSE Memory Support driver + * + * Copyright (c) 2017 PrasannaKumar Muralidharan prasannatsmkumar@gmail.com + * Copyright (c) 2020 H. Nikolaus Schaller hns@goldelico.com + */ + +/* + * Currently supports JZ4780 efuse which has 8K programmable bit. + * Efuse is separated into seven segments as below: + * + * ----------------------------------------------------------------------- + * | 64 bit | 128 bit | 128 bit | 3520 bit | 8 bit | 2296 bit | 2048 bit | + * ----------------------------------------------------------------------- + * + * The rom itself is accessed using a 9 bit address line and an 8 word wide bus + * which reads/writes based on strobes. The strobe is configured in the config + * register and is based on number of cycles of the bus clock. + * + * Driver supports read only as the writes are done in the Factory. + */ + +#include <linux/bitops.h> +#include <linux/clk.h> +#include <linux/module.h> +#include <linux/nvmem-provider.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/timer.h> + +#define JZ_EFUCTRL (0x0) /* Control Register */ +#define JZ_EFUCFG (0x4) /* Configure Register*/ +#define JZ_EFUSTATE (0x8) /* Status Register */ +#define JZ_EFUDATA(n) (0xC + (n)*4) + +#define JZ_EFUSE_START_ADDR 0x200 + +#define JZ_EFUSE_EFUCTRL_CS BIT(30) +#define JZ_EFUSE_EFUCTRL_ADDR_MASK 0x1FF +#define JZ_EFUSE_EFUCTRL_ADDR_SHIFT 21 +#define JZ_EFUSE_EFUCTRL_LEN_MASK 0x1F +#define JZ_EFUSE_EFUCTRL_LEN_SHIFT 16 +#define JZ_EFUSE_EFUCTRL_PG_EN BIT(15) +#define JZ_EFUSE_EFUCTRL_WR_EN BIT(1) +#define JZ_EFUSE_EFUCTRL_RD_EN BIT(0) + +#define JZ_EFUSE_EFUCFG_INT_EN BIT(31) +#define JZ_EFUSE_EFUCFG_RD_ADJ_MASK 0xF +#define JZ_EFUSE_EFUCFG_RD_ADJ_SHIFT 20 +#define JZ_EFUSE_EFUCFG_RD_STR_MASK 0xF +#define JZ_EFUSE_EFUCFG_RD_STR_SHIFT 16 +#define JZ_EFUSE_EFUCFG_WR_ADJ_MASK 0xF +#define JZ_EFUSE_EFUCFG_WR_ADJ_SHIFT 12 +#define JZ_EFUSE_EFUCFG_WR_STR_MASK 0xFFF +#define JZ_EFUSE_EFUCFG_WR_STR_SHIFT 0 + +#define JZ_EFUSE_EFUSTATE_WR_DONE BIT(1) +#define JZ_EFUSE_EFUSTATE_RD_DONE BIT(0) + +struct jz4780_efuse { + struct device *dev; + void __iomem *iomem; + struct clk *clk; + unsigned int rd_adj; + unsigned int rd_strobe; +}; + +/* We read 32 byte chunks to avoid complexity in the driver. */ +static int jz4780_efuse_read_32bytes(struct jz4780_efuse *efuse, char *buf, + unsigned int addr) +{ + unsigned int tmp = 0; + int i = 0; + int timeout = 1000; + int size = 32; + + /* 1. Set config register */ + tmp = readl(efuse->iomem + JZ_EFUCFG); + tmp &= ~((JZ_EFUSE_EFUCFG_RD_ADJ_MASK << JZ_EFUSE_EFUCFG_RD_ADJ_SHIFT) + | (JZ_EFUSE_EFUCFG_RD_STR_MASK << JZ_EFUSE_EFUCFG_RD_STR_SHIFT)); + tmp |= (efuse->rd_adj << JZ_EFUSE_EFUCFG_RD_ADJ_SHIFT) + | (efuse->rd_strobe << JZ_EFUSE_EFUCFG_RD_STR_SHIFT); + writel(tmp, efuse->iomem + JZ_EFUCFG); + + /* + * 2. Set control register to indicate what to read data address, + * read data numbers and read enable. + */ + tmp = readl(efuse->iomem + JZ_EFUCTRL); + tmp &= ~(JZ_EFUSE_EFUCFG_RD_STR_SHIFT + | (JZ_EFUSE_EFUCTRL_ADDR_MASK << JZ_EFUSE_EFUCTRL_ADDR_SHIFT) + | JZ_EFUSE_EFUCTRL_PG_EN | JZ_EFUSE_EFUCTRL_WR_EN + | JZ_EFUSE_EFUCTRL_WR_EN); + + /* Need to select CS bit if address accesses upper 4Kbits memory */ + if (addr >= (JZ_EFUSE_START_ADDR + 512)) + tmp |= JZ_EFUSE_EFUCTRL_CS; + + tmp |= (addr << JZ_EFUSE_EFUCTRL_ADDR_SHIFT) + | ((size - 1) << JZ_EFUSE_EFUCTRL_LEN_SHIFT) + | JZ_EFUSE_EFUCTRL_RD_EN; + writel(tmp, efuse->iomem + JZ_EFUCTRL); + + /* + * 3. Wait status register RD_DONE set to 1 or EFUSE interrupted, + * software can read EFUSE data buffer 0 - 8 registers. + */ + do { + tmp = readl(efuse->iomem + JZ_EFUSTATE); + usleep_range(1000, 2000); + if (timeout--) + break; + } while (!(tmp & JZ_EFUSE_EFUSTATE_RD_DONE)); + + if (timeout <= 0) { + dev_err(efuse->dev, "Timed out while reading\n"); + return -EAGAIN; + } + + for (i = 0; i < (size / 4); i++) + *((unsigned int *)(buf + i * 4)) + = readl(efuse->iomem + JZ_EFUDATA(i)); + + return 0; +} + +/* main entry point */ +static int jz4780_efuse_read(void *context, unsigned int offset, + void *val, size_t bytes) +{ + struct jz4780_efuse *efuse = context; + int ret; + + while (bytes > 0) { + unsigned int start = offset & ~(32 - 1); + unsigned chunk = min(bytes, (start + 32 - offset)); + + if (start == offset && chunk == 32) { + ret = jz4780_efuse_read_32bytes(efuse, val, start); + if (ret < 0) + return ret; + + } else { + char buf[32]; + ret = jz4780_efuse_read_32bytes(efuse, buf, start); + if (ret < 0) + return ret; + + memcpy(val, &buf[offset - start], chunk); + } + + val += chunk; + offset += chunk; + bytes -= chunk; + } + + return 0; +} + +static struct nvmem_config jz4780_efuse_nvmem_config = { + .name = "jz4780-efuse", + .read_only = true, + .size = 1024, + .word_size = 1, + .stride = 1, + .owner = THIS_MODULE, + .reg_read = jz4780_efuse_read, +}; + +static int jz4780_efuse_probe(struct platform_device *pdev) +{ + struct nvmem_device *nvmem; + struct jz4780_efuse *efuse; + struct resource *res; + unsigned long clk_rate; + struct device *dev = &pdev->dev; + + efuse = devm_kzalloc(&pdev->dev, sizeof(*efuse), GFP_KERNEL); + if (!efuse) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + efuse->iomem = devm_ioremap(&pdev->dev, res->start, resource_size(res)); + if (IS_ERR(efuse->iomem)) + return PTR_ERR(efuse->iomem); + + efuse->clk = devm_clk_get(&pdev->dev, "bus_clk"); + if (IS_ERR(efuse->clk)) + return PTR_ERR(efuse->clk); + + clk_rate = clk_get_rate(efuse->clk); + /* + * rd_adj and rd_strobe are 4 bit values + * bus clk period * (rd_adj + 1) > 6.5ns + * bus clk period * (rd_adj + 5 + rd_strobe) > 35ns + */ + efuse->rd_adj = (((6500 * (clk_rate / 1000000)) / 1000000) + 1) - 1; + efuse->rd_strobe = ((((35000 * (clk_rate / 1000000)) / 1000000) + 1) + - 5 - efuse->rd_adj); + + if ((efuse->rd_adj > 0x1F) || (efuse->rd_strobe > 0x1F)) { + dev_err(&pdev->dev, "Cannot set clock configuration\n"); + return -EINVAL; + } + efuse->dev = dev; + + jz4780_efuse_nvmem_config.dev = &pdev->dev; + jz4780_efuse_nvmem_config.priv = efuse; + + nvmem = nvmem_register(&jz4780_efuse_nvmem_config); + if (IS_ERR(nvmem)) + return PTR_ERR(nvmem); + + platform_set_drvdata(pdev, nvmem); + + return 0; +} + +static int jz4780_efuse_remove(struct platform_device *pdev) +{ + struct nvmem_device *nvmem = platform_get_drvdata(pdev); + + nvmem_unregister(nvmem); + + return 0; +} + +static const struct of_device_id jz4780_efuse_match[] = { + { .compatible = "ingenic,jz4780-efuse" }, + { /* sentinel */ }, +}; +MODULE_DEVICE_TABLE(of, jz4780_efuse_match); + +static struct platform_driver jz4780_efuse_driver = { + .probe = jz4780_efuse_probe, + .remove = jz4780_efuse_remove, + .driver = { + .name = "jz4780-efuse", + .of_match_table = jz4780_efuse_match, + }, +}; +module_platform_driver(jz4780_efuse_driver); + +MODULE_AUTHOR("PrasannaKumar Muralidharan prasannatsmkumar@gmail.com"); +MODULE_AUTHOR("H. Nikolaus Schaller hns@goldelico.com"); +MODULE_DESCRIPTION("Ingenic JZ4780 efuse driver"); +MODULE_LICENSE("GPL v2");