lib: sbi: Move RISC-V PMP encoding functions to sbi_pmp.c

Create a new file for handling the RISC-V PMP format and the new pmp_t
type, as opposed to hart PMP CSR specific access.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20260430045528.420437-4-npiggin@gmail.com
Signed-off-by: Anup Patel <anup@brainfault.org>

include/sbi/sbi_pmp.h

@@ -0,0 +1,22 @@
+/*
+ * SPDX-FileCopyrightText: (c) 2025-2026 Tenstorrent USA, Inc.
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#ifndef __SBI_PMP_H__
+#define __SBI_PMP_H__
+
+#include <sbi/sbi_types.h>
+
+struct pmp {
+	unsigned long addr;
+	u8 cfg;
+};
+typedef struct pmp pmp_t;
+
+int sbi_pmp_encode(pmp_t *pmp, unsigned long prot, unsigned long addr,
+		    unsigned long log2len);
+int sbi_pmp_decode(pmp_t *pmp, unsigned long *prot, unsigned long *addr,
+		    unsigned long *log2len);
+
+#endif

lib/sbi/objects.mk

@@ -87,6 +87,7 @@ libsbi-objs-y += sbi_init.o
 libsbi-objs-y += sbi_ipi.o
 libsbi-objs-y += sbi_irqchip.o
 libsbi-objs-y += sbi_platform.o
+libsbi-objs-y += sbi_pmp.o
 libsbi-objs-y += sbi_pmu.o
 libsbi-objs-y += sbi_dbtr.o
 libsbi-objs-y += sbi_mpxy.o

lib/sbi/riscv_asm.c

@@ -12,6 +12,7 @@
 #include <sbi/sbi_error.h>
 #include <sbi/sbi_platform.h>
 #include <sbi/sbi_console.h>
+#include <sbi/sbi_pmp.h>
 
 /* determine CPU extension, return non-zero support */
 int misa_extension_imp(char ext)
@@ -272,27 +273,6 @@ void csr_write_num(int csr_num, unsigned long val)
 #undef switchcase_csr_write
 }
 
-struct pmp {
-	unsigned long addr;
-	u8 cfg;
-};
-typedef struct pmp pmp_t;
-
-static unsigned long ctz(unsigned long x)
-{
-	unsigned long ret = 0;
-
-	if (x == 0)
-		return 8 * sizeof(x);
-
-	while (!(x & 1UL)) {
-		ret++;
-		x = x >> 1;
-	}
-
-	return ret;
-}
-
 int pmp_disable(unsigned int n)
 {
 	int pmpcfg_csr, pmpcfg_shift;
@@ -336,35 +316,6 @@ int is_pmp_entry_mapped(unsigned long entry)
 	return false;
 }
 
-static int pmp_encode(pmp_t *pmp, unsigned long prot, unsigned long addr,
-		      unsigned long log2len)
-{
-	/* check parameters */
-	if (log2len > __riscv_xlen || log2len < PMP_SHIFT)
-		return SBI_EINVAL;
-
-	/* encode PMP config */
-	prot &= ~PMP_A;
-	prot |= (log2len == PMP_SHIFT) ? PMP_A_NA4 : PMP_A_NAPOT;
-	pmp->cfg = prot;
-
-	/* encode PMP address */
-	if (log2len == PMP_SHIFT) {
-		pmp->addr = (addr >> PMP_SHIFT);
-	} else {
-		if (log2len == __riscv_xlen) {
-			pmp->addr = -1UL;
-		} else {
-			unsigned long addrmask;
-			addrmask = (1UL << (log2len - PMP_SHIFT)) - 1;
-			pmp->addr = ((addr >> PMP_SHIFT) & ~addrmask);
-			pmp->addr |= (addrmask >> 1);
-		}
-	}
-
-	return SBI_OK;
-}
-
 int pmp_set(unsigned int n, unsigned long prot, unsigned long addr,
 	    unsigned long log2len)
 {
@@ -377,7 +328,7 @@ int pmp_set(unsigned int n, unsigned long prot, unsigned long addr,
 	if (n >= PMP_COUNT)
 		return SBI_EINVAL;
 
-	rc = pmp_encode(&pmp, prot, addr, log2len);
+	rc = sbi_pmp_encode(&pmp, prot, addr, log2len);
 	if (rc)
 		return rc;
 
@@ -403,44 +354,6 @@ int pmp_set(unsigned int n, unsigned long prot, unsigned long addr,
 	return 0;
 }
 
-static int pmp_decode(pmp_t *pmp, unsigned long *prot_out, unsigned long *addr_out,
-		      unsigned long *log2len)
-{
-	unsigned long prot;
-	unsigned long t1, addr, len;
-
-	/* check parameters */
-	if (!prot_out || !addr_out || !log2len)
-		return SBI_EINVAL;
-	*prot_out = *addr_out = *log2len = 0;
-
-	/* decode PMP config */
-	prot = pmp->cfg;
-
-	/* decode PMP address */
-	if ((prot & PMP_A) == PMP_A_NAPOT) {
-		addr = pmp->addr;
-		if (addr == -1UL) {
-			addr	= 0;
-			len	= __riscv_xlen;
-		} else {
-			t1	= ctz(~addr);
-			addr	= (addr & ~((1UL << t1) - 1)) << PMP_SHIFT;
-			len	= (t1 + PMP_SHIFT + 1);
-		}
-	} else {
-		addr	= pmp->addr << PMP_SHIFT;
-		len	= PMP_SHIFT;
-	}
-
-	/* return details */
-	*prot_out    = prot;
-	*addr_out    = addr;
-	*log2len     = len;
-
-	return SBI_OK;
-}
-
 int pmp_get(unsigned int n, unsigned long *prot_out, unsigned long *addr_out,
 	    unsigned long *log2len)
 {
@@ -468,5 +381,5 @@ int pmp_get(unsigned int n, unsigned long *prot_out, unsigned long *addr_out,
 	pmp.cfg = (csr_read_num(pmpcfg_csr) & cfgmask) >> pmpcfg_shift;
 	pmp.addr = csr_read_num(pmpaddr_csr);
 
-	return pmp_decode(&pmp, prot_out, addr_out, log2len);
+	return sbi_pmp_decode(&pmp, prot_out, addr_out, log2len);
 }

lib/sbi/sbi_pmp.c

@@ -0,0 +1,96 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *   Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <sbi/riscv_asm.h>
+#include <sbi/riscv_encoding.h>
+#include <sbi/sbi_error.h>
+#include <sbi/sbi_console.h>
+#include <sbi/sbi_pmp.h>
+
+static unsigned long ctz(unsigned long x)
+{
+	unsigned long ret = 0;
+
+	if (x == 0)
+		return 8 * sizeof(x);
+
+	while (!(x & 1UL)) {
+		ret++;
+		x = x >> 1;
+	}
+
+	return ret;
+}
+
+int sbi_pmp_encode(pmp_t *pmp, unsigned long prot, unsigned long addr,
+		    unsigned long log2len)
+{
+	/* check parameters */
+	if (log2len > __riscv_xlen || log2len < PMP_SHIFT)
+		return SBI_EINVAL;
+
+	/* encode PMP config */
+	prot &= ~PMP_A;
+	prot |= (log2len == PMP_SHIFT) ? PMP_A_NA4 : PMP_A_NAPOT;
+	pmp->cfg = prot;
+
+	/* encode PMP address */
+	if (log2len == PMP_SHIFT) {
+		pmp->addr = (addr >> PMP_SHIFT);
+	} else {
+		if (log2len == __riscv_xlen) {
+			pmp->addr = -1UL;
+		} else {
+			unsigned long addrmask;
+			addrmask = (1UL << (log2len - PMP_SHIFT)) - 1;
+			pmp->addr = ((addr >> PMP_SHIFT) & ~addrmask);
+			pmp->addr |= (addrmask >> 1);
+		}
+	}
+
+	return SBI_OK;
+}
+
+int sbi_pmp_decode(pmp_t *pmp, unsigned long *prot_out, unsigned long *addr_out,
+		    unsigned long *log2len)
+{
+	unsigned long prot;
+	unsigned long t1, addr, len;
+
+	/* check parameters */
+	if (!prot_out || !addr_out || !log2len)
+		return SBI_EINVAL;
+	*prot_out = *addr_out = *log2len = 0;
+
+	/* decode PMP config */
+	prot = pmp->cfg;
+
+	/* decode PMP address */
+	if ((prot & PMP_A) == PMP_A_NAPOT) {
+		addr = pmp->addr;
+		if (addr == -1UL) {
+			addr	= 0;
+			len	= __riscv_xlen;
+		} else {
+			t1	= ctz(~addr);
+			addr	= (addr & ~((1UL << t1) - 1)) << PMP_SHIFT;
+			len	= (t1 + PMP_SHIFT + 1);
+		}
+	} else {
+		addr	= pmp->addr << PMP_SHIFT;
+		len	= PMP_SHIFT;
+	}
+
+	/* return details */
+	*prot_out    = prot;
+	*addr_out    = addr;
+	*log2len     = len;
+
+	return SBI_OK;
+}