drivers/soc/litex: add LiteX SoC Controller driver

This commit adds driver for the FPGA-based LiteX SoC
Controller from LiteX SoC builder.

Co-developed-by: Mateusz Holenko <mholenko@antmicro.com>
Signed-off-by: Mateusz Holenko <mholenko@antmicro.com>
Signed-off-by: Pawel Czarnecki <pczarnecki@internships.antmicro.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 102 insertions, 0 deletions

diff --git a/include/linux/litex.h b/include/linux/litex.h
new file mode 100644
index 000000000000..40f5be503593
--- /dev/null
+++ b/include/linux/litex.h
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Common LiteX header providing
+ * helper functions for accessing CSRs.
+ *
+ * Implementation of the functions is provided by
+ * the LiteX SoC Controller driver.
+ *
+ * Copyright (C) 2019-2020 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>
+
+/*
+ * The parameters below are true for LiteX SoCs configured for 8-bit CSR Bus,
+ * 32-bit aligned.
+ *
+ * Supporting other configurations will require extending the logic in this
+ * header and in the LiteX SoC controller driver.
+ */
+#define LITEX_REG_SIZE	  0x4
+#define LITEX_SUBREG_SIZE	0x1
+#define LITEX_SUBREG_SIZE_BIT	 (LITEX_SUBREG_SIZE * 8)
+
+#define WRITE_LITEX_SUBREGISTER(val, base_offset, subreg_id) \
+	writel((u32 __force)cpu_to_le32(val), base_offset + (LITEX_REG_SIZE * subreg_id))
+
+#define READ_LITEX_SUBREGISTER(base_offset, subreg_id) \
+	le32_to_cpu((__le32 __force)readl(base_offset + (LITEX_REG_SIZE * subreg_id)))
+
+void litex_set_reg(void __iomem *reg, unsigned long reg_sz, unsigned long val);
+
+unsigned long litex_get_reg(void __iomem *reg, unsigned long reg_sz);
+
+static inline void litex_write8(void __iomem *reg, u8 val)
+{
+	WRITE_LITEX_SUBREGISTER(val, reg, 0);
+}
+
+static inline void litex_write16(void __iomem *reg, u16 val)
+{
+	WRITE_LITEX_SUBREGISTER(val >> 8, reg, 0);
+	WRITE_LITEX_SUBREGISTER(val, reg, 1);
+}
+
+static inline void litex_write32(void __iomem *reg, u32 val)
+{
+	WRITE_LITEX_SUBREGISTER(val >> 24, reg, 0);
+	WRITE_LITEX_SUBREGISTER(val >> 16, reg, 1);
+	WRITE_LITEX_SUBREGISTER(val >> 8, reg, 2);
+	WRITE_LITEX_SUBREGISTER(val, reg, 3);
+}
+
+static inline void litex_write64(void __iomem *reg, u64 val)
+{
+	WRITE_LITEX_SUBREGISTER(val >> 56, reg, 0);
+	WRITE_LITEX_SUBREGISTER(val >> 48, reg, 1);
+	WRITE_LITEX_SUBREGISTER(val >> 40, reg, 2);
+	WRITE_LITEX_SUBREGISTER(val >> 32, reg, 3);
+	WRITE_LITEX_SUBREGISTER(val >> 24, reg, 4);
+	WRITE_LITEX_SUBREGISTER(val >> 16, reg, 5);
+	WRITE_LITEX_SUBREGISTER(val >> 8, reg, 6);
+	WRITE_LITEX_SUBREGISTER(val, reg, 7);
+}
+
+static inline u8 litex_read8(void __iomem *reg)
+{
+	return READ_LITEX_SUBREGISTER(reg, 0);
+}
+
+static inline u16 litex_read16(void __iomem *reg)
+{
+	return (READ_LITEX_SUBREGISTER(reg, 0) << 8)
+		| (READ_LITEX_SUBREGISTER(reg, 1));
+}
+
+static inline u32 litex_read32(void __iomem *reg)
+{
+	return (READ_LITEX_SUBREGISTER(reg, 0) << 24)
+		| (READ_LITEX_SUBREGISTER(reg, 1) << 16)
+		| (READ_LITEX_SUBREGISTER(reg, 2) << 8)
+		| (READ_LITEX_SUBREGISTER(reg, 3));
+}
+
+static inline u64 litex_read64(void __iomem *reg)
+{
+	return ((u64)READ_LITEX_SUBREGISTER(reg, 0) << 56)
+		| ((u64)READ_LITEX_SUBREGISTER(reg, 1) << 48)
+		| ((u64)READ_LITEX_SUBREGISTER(reg, 2) << 40)
+		| ((u64)READ_LITEX_SUBREGISTER(reg, 3) << 32)
+		| ((u64)READ_LITEX_SUBREGISTER(reg, 4) << 24)
+		| ((u64)READ_LITEX_SUBREGISTER(reg, 5) << 16)
+		| ((u64)READ_LITEX_SUBREGISTER(reg, 6) << 8)
+		| ((u64)READ_LITEX_SUBREGISTER(reg, 7));
+}
+
+#endif /* _LINUX_LITEX_H */