Merge patch series "Add PMEM support for RISC-V"

Anup Patel <apatel@ventanamicro.com> says:

The Linux NVDIMM PEM drivers require arch support to map and access the
persistent memory device. This series adds RISC-V PMEM support using
recently added Svpbmt and Zicbom support.

* b4-shazam-merge:
  RISC-V: Enable PMEM drivers
  RISC-V: Implement arch specific PMEM APIs
  RISC-V: Fix MEMREMAP_WB for systems with Svpbmt

Link: https://lore.kernel.org/r/20221114090536.1662624-1-apatel@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/Kconfig

@@ -25,6 +25,7 @@ config RISCV
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_MMIOWB
+	select ARCH_HAS_PMEM_API
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_SET_DIRECT_MAP if MMU
 	select ARCH_HAS_SET_MEMORY if MMU

arch/riscv/configs/defconfig

@@ -161,6 +161,7 @@ CONFIG_VIRTIO_MMIO=y
 CONFIG_RPMSG_CHAR=y
 CONFIG_RPMSG_CTRL=y
 CONFIG_RPMSG_VIRTIO=y
+CONFIG_LIBNVDIMM=y
 CONFIG_EXT4_FS=y
 CONFIG_EXT4_FS_POSIX_ACL=y
 CONFIG_EXT4_FS_SECURITY=y

arch/riscv/include/asm/io.h

@@ -135,4 +135,9 @@ __io_writes_outs(outs, u64, q, __io_pbr(), __io_paw())
 
 #include <asm-generic/io.h>
 
+#ifdef CONFIG_MMU
+#define arch_memremap_wb(addr, size)	\
+	((__force void *)ioremap_prot((addr), (size), _PAGE_KERNEL))
+#endif
+
 #endif /* _ASM_RISCV_IO_H */

arch/riscv/mm/Makefile

@@ -14,6 +14,7 @@ obj-$(CONFIG_MMU) += fault.o pageattr.o
 obj-y += cacheflush.o
 obj-y += context.o
 obj-y += pgtable.o
+obj-y += pmem.o
 
 ifeq ($(CONFIG_MMU),y)
 obj-$(CONFIG_SMP) += tlbflush.o

arch/riscv/mm/pmem.c

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022 Ventana Micro Systems Inc.
+ */
+
+#include <linux/export.h>
+#include <linux/libnvdimm.h>
+
+#include <asm/cacheflush.h>
+
+void arch_wb_cache_pmem(void *addr, size_t size)
+{
+	ALT_CMO_OP(clean, addr, size, riscv_cbom_block_size);
+}
+EXPORT_SYMBOL_GPL(arch_wb_cache_pmem);
+
+void arch_invalidate_pmem(void *addr, size_t size)
+{
+	ALT_CMO_OP(inval, addr, size, riscv_cbom_block_size);
+}
+EXPORT_SYMBOL_GPL(arch_invalidate_pmem);