[PATCH v2 2/4] litex: add common LiteX header

[Mateusz Holenko <mholenko@antmicro.com>]

It provides helper CSR access functions used by all
LiteX drivers.

Signed-off-by: Mateusz Holenko <mholenko@antmicro.com>
---
This commit has been introduced in v2 of the patchset.

 MAINTAINERS           |  6 +++++
 include/linux/litex.h | 59 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)
 create mode 100644 include/linux/litex.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 296de2b51c83..eaa51209bfb2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9493,6 +9493,12 @@ F:	Documentation/misc-devices/lis3lv02d.rst
 F:	drivers/misc/lis3lv02d/
 F:	drivers/platform/x86/hp_accel.c
 
+LITEX PLATFORM
+M:	Karol Gugala <kgugala@antmicro.com>
+M:	Mateusz Holenko <mholenko@antmicro.com>
+S:	Maintained
+F:	include/linux/litex.h
+
 LIVE PATCHING
 M:	Josh Poimboeuf <jpoimboe@redhat.com>
 M:	Jiri Kosina <jikos@kernel.org>
diff --git a/include/linux/litex.h b/include/linux/litex.h
new file mode 100644
index 000000000000..e793d2d7c881
--- /dev/null
+++ b/include/linux/litex.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Common LiteX header providing
+ * helper functions for accessing CSRs.
+ *
+ * Copyright (C) 2019 Antmicro <www.antmicro.com>
+ */
+
+#ifndef _LINUX_LITEX_H
+#define _LINUX_LITEX_H
+
+#include <linux/io.h>
+#include <linux/types.h>
+#include <linux/compiler_types.h>
+
+#define LITEX_REG_SIZE             0x4
+#define LITEX_SUBREG_SIZE          0x1
+#define LITEX_SUBREG_SIZE_BIT      (LITEX_SUBREG_SIZE * 8)
+
+#ifdef __LITTLE_ENDIAN
+# define LITEX_READ_REG(addr)                  ioread32(addr)
+# define LITEX_READ_REG_OFF(addr, off)         ioread32(addr + off)
+# define LITEX_WRITE_REG(val, addr)            iowrite32(val, addr)
+# define LITEX_WRITE_REG_OFF(val, addr, off)   iowrite32(val, addr + off)
+#else
+# define LITEX_READ_REG(addr)                  ioread32be(addr)
+# define LITEX_READ_REG_OFF(addr, off)         ioread32be(addr + off)
+# define LITEX_WRITE_REG(val, addr)            iowrite32be(val, addr)
+# define LITEX_WRITE_REG_OFF(val, addr, off)   iowrite32be(val, addr + off)
+#endif
+
+/* Helper functions for manipulating LiteX registers */
+
+static inline void litex_set_reg(void __iomem *reg, u32 reg_size, u32 val)
+{
+	u32 shifted_data, shift, i;
+
+	for (i = 0; i < reg_size; ++i) {
+		shift = ((reg_size - i - 1) * LITEX_SUBREG_SIZE_BIT);
+		shifted_data = val >> shift;
+		LITEX_WRITE_REG(shifted_data, reg + (LITEX_REG_SIZE * i));
+	}
+}
+
+static inline u32 litex_get_reg(void __iomem *reg, u32 reg_size)
+{
+	u32 shifted_data, shift, i;
+	u32 result = 0;
+
+	for (i = 0; i < reg_size; ++i) {
+		shifted_data = LITEX_READ_REG(reg + (LITEX_REG_SIZE * i));
+		shift = ((reg_size - i - 1) * LITEX_SUBREG_SIZE_BIT);
+		result |= (shifted_data << shift);
+	}
+
+	return result;
+}
+
+#endif /* _LINUX_LITEX_H */
-- 
2.23.0