[PATCH v2 08/11] nvmem: add kvx otp non volatile regbank support

[Jules Maselbas]

From: Clement Leger <clement.leger at bootlin.com>

Backport Linux driver to barebox to access nvmem.

Signed-off-by: Clement Leger <clement.leger at bootlin.com>
Signed-off-by: Jules Maselbas <jmaselbas at kalray.eu>
---
changes in v2:
 - removed if (allways set skip to 0 after the memcopy)
---
 drivers/nvmem/Kconfig      |  7 +++
 drivers/nvmem/Makefile     |  3 ++
 drivers/nvmem/kvx-otp-nv.c | 98 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 108 insertions(+)
 create mode 100644 drivers/nvmem/kvx-otp-nv.c

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 7b1ebe1d68..2e60734156 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -76,6 +76,13 @@ config STM32_BSEC_WRITE
 	    mw -l -d /dev/stm32-bsec 0x000000e4+4 0x78563412
 	    mw -l -d /dev/stm32-bsec 0x000000e8+4 0x0000bc9a
 
+config KVX_OTP_NV
+	tristate "kalray KVX OTP Non volatile regs Support"
+	depends on KVX
+	help
+	  This is a simple driver to dump specified values of KVX OTP non
+	  volatile regs.
+
 config STARFIVE_OTP
 	tristate "Starfive OTP Supprot"
 	depends on SOC_STARFIVE
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 5865919612..62a1f925dd 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -24,4 +24,7 @@ nvmem_eeprom_93xx46-y		:= eeprom_93xx46.o
 obj-$(CONFIG_STM32_BSEC)	+= nvmem_bsec.o
 nvmem_bsec-y			:= bsec.o
 
+obj-$(CONFIG_KVX_OTP_NV)	+= nvmem-kvx-otp-nv.o
+nvmem-kvx-otp-nv-y		:= kvx-otp-nv.o
+
 obj-$(CONFIG_STARFIVE_OTP)	+= starfive-otp.o
diff --git a/drivers/nvmem/kvx-otp-nv.c b/drivers/nvmem/kvx-otp-nv.c
new file mode 100644
index 0000000000..d614c16e1e
--- /dev/null
+++ b/drivers/nvmem/kvx-otp-nv.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2020 Kalray Inc., Clément Léger
+ */
+
+#include <common.h>
+#include <driver.h>
+#include <malloc.h>
+#include <xfuncs.h>
+#include <errno.h>
+#include <init.h>
+#include <net.h>
+#include <io.h>
+
+#include <linux/nvmem-provider.h>
+
+#define OTP_NV_ALIGN		4
+#define OTP_NV_ALIGN_MASK	(OTP_NV_ALIGN - 1)
+
+struct kvx_otp_nv_priv {
+	void __iomem *base;
+};
+
+static int kvx_otp_nv_read(void *context, unsigned int offset,
+			  void *_val, size_t bytes)
+{
+	struct kvx_otp_nv_priv *priv = context;
+	u8 *val = _val;
+	u32 tmp, copy_size;
+	u8 skip = offset & OTP_NV_ALIGN_MASK;
+
+	offset &= ~OTP_NV_ALIGN_MASK;
+
+	while (bytes) {
+		tmp = readl(priv->base + offset);
+		if (skip != 0)
+			copy_size = min(OTP_NV_ALIGN - skip, (int) bytes);
+		else
+			copy_size = min(bytes, sizeof(tmp));
+
+		memcpy(val, ((u8 *) &tmp) + skip, copy_size);
+		skip = 0;
+
+		bytes -= copy_size;
+		val += copy_size;
+		offset += OTP_NV_ALIGN;
+	}
+
+	return 0;
+}
+
+static const struct nvmem_bus kvx_otp_nv_bus = {
+	.read = kvx_otp_nv_read,
+};
+
+static const struct of_device_id kvx_otp_nv_match[] = {
+	{ .compatible = "kalray,kvx-otp-nv" },
+	{ /* sentinel */},
+};
+
+static int kvx_otp_nv_probe(struct device_d *dev)
+{
+	struct resource *res;
+	struct nvmem_device *nvmem;
+	struct nvmem_config econfig = { 0 };
+	struct kvx_otp_nv_priv *priv;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	res = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(res))
+		return PTR_ERR(res);
+
+	priv->base = IOMEM(res->start);
+
+	econfig.name = "kvx-nv-regbank";
+	econfig.stride = 1;
+	econfig.word_size = 1;
+	econfig.size = resource_size(res);
+	econfig.dev = dev;
+	econfig.priv = priv;
+	econfig.bus = &kvx_otp_nv_bus;
+
+	dev->priv = priv;
+
+	nvmem = nvmem_register(&econfig);
+
+	return PTR_ERR_OR_ZERO(nvmem);
+}
+
+static struct driver_d kvx_otp_nv_driver = {
+	.name	= "kvx-otp-nv",
+	.probe	= kvx_otp_nv_probe,
+	.of_compatible = DRV_OF_COMPAT(kvx_otp_nv_match),
+};
+postcore_platform_driver(kvx_otp_nv_driver);
-- 
2.17.1