On 05.03.2021 11:02, Srinivas Kandagatla wrote:
On 04/03/2021 14:41, Rafał Miłecki wrote:
From: Rafał Miłecki <ra...@milecki.pl>
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 <ra...@milecki.pl>
---
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 <ra...@milecki.pl>
+ */
+
+#include <linux/io.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/platform_device.h>
+
+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);
+
You could just do this!
while (bytes--)
*val++ = readb(priv->base + offset + i++);
Do you mean that as replacement for "memcpy_fromio" or the whole
function code?
The reason for using __ioread32_copy() was to improve reading
performance (using aligned 32 bit access where possible). I'm not sure
if that really matters?
P.S.
Please don't yell at me in every sentence :( Makes me a bit sad :(
