[PATCH 05/20] nvmem: add StarFive OTP support

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

The OTP holds the ethernet MAC address. Add a driver, so barebox can
read it out.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/nvmem/Kconfig        |   8 ++
 drivers/nvmem/Makefile       |   2 +
 drivers/nvmem/starfive-otp.c | 227 +++++++++++++++++++++++++++++++++++
 3 files changed, 237 insertions(+)
 create mode 100644 drivers/nvmem/starfive-otp.c

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index e4a72b1431a9..377d6c8b15cc 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -59,4 +59,12 @@ config STM32_BSEC
 	  This adds support for the STM32 OTP controller. Reads and writes
 	  to will go to the shadow RAM, not the OTP fuses themselvers.
 
+config STARFIVE_OTP
+	tristate "Starfive OTP Supprot"
+	depends on SOC_STARFIVE
+	depends on OFDEVICE
+	help
+	  This adds support for the StarFive OTP controller. Only reading
+	  is currently supported.
+
 endif
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 617e3725a726..83ff3d23cb44 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -20,3 +20,5 @@ nvmem_eeprom_93xx46-y		:= eeprom_93xx46.o
 
 obj-$(CONFIG_STM32_BSEC)	+= nvmem_bsec.o
 nvmem_bsec-y			:= bsec.o
+
+obj-$(CONFIG_STARFIVE_OTP)	+= starfive-otp.o
diff --git a/drivers/nvmem/starfive-otp.c b/drivers/nvmem/starfive-otp.c
new file mode 100644
index 000000000000..5d1a94364d81
--- /dev/null
+++ b/drivers/nvmem/starfive-otp.c
@@ -0,0 +1,227 @@
+// SPDX_License-Identifier: GPL-2.0
+/*
+ *   Copyright 2021 StarFive, Inc
+ */
+
+#include <common.h>
+#include <driver.h>
+#include <malloc.h>
+#include <xfuncs.h>
+#include <errno.h>
+#include <gpiod.h>
+#include <init.h>
+#include <net.h>
+#include <io.h>
+#include <of.h>
+#include <regmap.h>
+#include <machine_id.h>
+#include <linux/reset.h>
+#include <linux/nvmem-provider.h>
+
+// otp reg offset
+#define OTP_CFGR        0x00
+#define OTPC_IER        0x04
+#define OTPC_SRR        0x08
+#define OTP_OPRR        0x0c
+#define OTPC_CTLR       0x10
+#define OTPC_ADDRR      0x14
+#define OTPC_DINR       0x18
+#define OTPC_DOUTR      0x1c
+
+#define OTP_EMPTY_CELL_VALUE  0xffffffffUL
+
+// cfgr (offset 0x00)
+#define OTP_CFGR_PRG_CNT_MASK   0xff
+#define OTP_CFGR_PRG_CNT_SHIFT  0
+#define OTP_CFGR_DIV_1US_MASK   0xff
+#define OTP_CFGR_DIV_1US_SHIFT  8
+#define OTP_CFGR_RD_CYC_MASK    0x0f
+#define OTP_CFGR_RD_CYC_SHIFT   16
+
+// ier (offset 0x04)
+#define OTPC_IER_DONE_IE        BIT(0)
+#define OTPC_IER_BUSY_OPR_IE    BIT(1)
+
+// srr (offset 0x08)
+#define OTPC_SRR_DONE           BIT(0)
+#define OTPC_SRR_BUSY_OPR       BIT(1)
+#define OTPC_SRR_INFO_RD_LOCK   BIT(29)
+#define OTPC_SRR_INFO_WR_LOCK   BIT(30)
+#define OTPC_SRR_BUSY           BIT(31)
+
+// oprr (offset 0x0c)
+#define OTP_OPRR_OPR_MASK           0x00000007
+#define OTP_OPRR_OPR_SHIFT          0
+
+#define OTP_OPR_STANDBY             0x0 // user mode
+#define OTP_OPR_READ                0x1 // user mode
+#define OTP_OPR_MARGIN_READ_PROG    0x2 // testing mode
+#define OTP_OPR_MARGIN_READ_INIT    0x3 // testing mode
+#define OTP_OPR_PROGRAM             0x4 // user mode
+#define OTP_OPR_DEEP_STANDBY        0x5 // user mode
+#define OTP_OPR_DEBUG               0x6 // user mode
+
+// ctlr (offset 0x10, see EG512X32TH028CW01_v1.0.pdf "Pin Description")
+#define OTPC_CTLR_PCE               BIT(0)
+#define OTPC_CTLR_PTM_MASK          0x0000000e
+#define OTPC_CTLR_PTM_SHIFT         1
+#define OTPC_CTLR_PDSTB             BIT(4)
+#define OTPC_CTLR_PTR               BIT(5)
+#define OTPC_CTLR_PPROG             BIT(6)
+#define OTPC_CTLR_PWE               BIT(7)
+#define OTPC_CTLR_PCLK              BIT(8)
+
+// addrr (offset 0x14)
+#define OTPC_ADDRR_PA_MASK          0x000001ff
+#define OTPC_ADDRR_PA_SHIFT         0
+
+/*
+ * data format:
+ * struct starfive_otp_data{
+ * 	char vendor[32];
+ * 	uint64_t sn;
+ * 	uint8_t mac_addr[6];
+ * 	uint8_t padding_0[2];
+ * }
+ */
+
+struct starfive_otp {
+	int power_gpio;
+	struct starfive_otp_regs __iomem *regs;
+};
+
+struct starfive_otp_regs {
+	/* TODO: add otp ememory_eg512x32 registers define */
+	u32 otp_cfg;		/* timing Register */
+	u32 otpc_ie;		/* interrupt Enable */
+	u32 otpc_sr;		/* status Register */
+	u32 otp_opr;		/* operation mode select Register */
+	u32 otpc_ctl;		/* otp control port */
+	u32 otpc_addr;		/* otp pa port */
+	u32 otpc_din;		/* otp pdin port */
+	u32 otpc_dout;		/* otp pdout */
+	u32 reserved[504];
+	u32 mem[512];
+};
+
+/*
+ * offset and size are assumed aligned to the size of the fuses (32-bit).
+ */
+static int starfive_otp_read(void *ctx, unsigned offset, unsigned *val)
+{
+	struct starfive_otp *priv = ctx;
+
+	gpio_set_active(priv->power_gpio, true);
+	mdelay(10);
+
+	//otp set to read mode
+	writel(OTP_OPR_READ, &priv->regs->otp_opr);
+	mdelay(5);
+
+	/* read all requested fuses */
+	*val = readl(&priv->regs->mem[offset / 4]);
+
+	gpio_set_active(priv->power_gpio, false);
+	mdelay(5);
+
+	return 0;
+}
+
+static int starfive_otp_write(void *ctx, unsigned offset, unsigned val)
+{
+	return -EOPNOTSUPP;
+}
+
+static struct regmap_bus starfive_otp_regmap_bus = {
+	.reg_read = starfive_otp_read,
+	.reg_write = starfive_otp_write,
+};
+
+static int starfive_otp_set_mac(struct device_node *rnode, struct regmap *map, unsigned offset)
+{
+	u8 mac[8];
+	int ret;
+
+	ret = regmap_bulk_read(map, offset, mac, 8);
+	if (ret)
+		return ret;
+
+	of_eth_register_ethaddr(rnode, mac);
+	return 0;
+}
+
+static int starfive_otp_probe(struct device_d *dev)
+{
+	struct starfive_otp *priv;
+	struct regmap_config config = {};
+	struct nvmem_device *nvmem;
+	struct resource *iores;
+	const __be32 *prop;
+	struct regmap *map;
+	u32 total_fuses;
+	int len, ret;
+
+	ret = device_reset(dev);
+	if (ret)
+		return ret;
+
+	iores = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(iores))
+		return PTR_ERR(iores);
+
+	ret = of_property_read_u32(dev->device_node, "fuse-count", &total_fuses);
+	if (ret < 0) {
+		dev_err(dev, "missing required fuse-count property\n");
+		return ret;
+	}
+
+	config.name = "starfive-otp";
+	config.reg_bits = 32;
+	config.val_bits = 32;
+	config.reg_stride = 4;
+	config.max_register = total_fuses;
+
+	priv = xzalloc(sizeof(*priv));
+
+	priv->regs = IOMEM(iores->start);
+	priv->power_gpio = gpiod_get(dev, "power", GPIOD_OUT_LOW);
+	if (priv->power_gpio < 0)
+		return priv->power_gpio;
+
+	map = regmap_init(dev, &starfive_otp_regmap_bus, priv, &config);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+
+	nvmem = nvmem_regmap_register(map, "starfive-otp");
+	if (IS_ERR(nvmem))
+		return PTR_ERR(nvmem);
+
+	prop = of_get_property(dev->device_node, "barebox,provide-mac-address", &len);
+	if (prop && len == 2 * sizeof(__be32)) {
+		struct device_node *rnode;
+		u32 phandle, offset;
+
+		phandle = be32_to_cpup(prop++);
+
+		rnode = of_find_node_by_phandle(phandle);
+		offset = be32_to_cpup(prop++);
+
+		ret = starfive_otp_set_mac(rnode, map, offset);
+		if (ret)
+			dev_warn(dev, "error setting MAC address: %pe\n", ERR_PTR(ret));
+	}
+
+	return 0;
+}
+
+static struct of_device_id starfive_otp_dt_ids[] = {
+	{ .compatible = "starfive,fu740-otp" },
+	{ /* sentinel */ }
+};
+
+static struct driver_d starfive_otp_driver = {
+	.name	= "starfive_otp",
+	.probe	= starfive_otp_probe,
+	.of_compatible = starfive_otp_dt_ids,
+};
+device_platform_driver(starfive_otp_driver);
-- 
2.29.2


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