lib: sbi: split PMP encoding and CSR access

Allow PMP encoding functions to be shared with non-hart PMP manipulation
by splitting encoding / decoding and hart PMP CSR access into their own
functions.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20260430045528.420437-3-npiggin@gmail.com
Signed-off-by: Anup Patel <anup@brainfault.org>

1 files changed, 73 insertions, 46 deletions

diff --git a/lib/sbi/riscv_asm.c b/lib/sbi/riscv_asm.c
index acb6b5e6..e33e3c36 100644
--- a/lib/sbi/riscv_asm.c
+++ b/lib/sbi/riscv_asm.c
@@ -336,70 +336,50 @@ int is_pmp_entry_mapped(unsigned long entry)
 	return false;
 }
 
-int pmp_set(unsigned int n, unsigned long prot, unsigned long addr,
-	    unsigned long log2len)
+static int pmp_encode(pmp_t *pmp, unsigned long prot, unsigned long addr,
+		      unsigned long log2len)
 {
-	int pmpcfg_csr, pmpcfg_shift, pmpaddr_csr;
-	unsigned long cfgmask, pmpcfg;
-	unsigned long addrmask;
-	pmp_t pmp;
-
 	/* check parameters */
-	if (n >= PMP_COUNT || log2len > __riscv_xlen || log2len < PMP_SHIFT)
+	if (log2len > __riscv_xlen || log2len < PMP_SHIFT)
 		return SBI_EINVAL;
 
-	/* calculate PMP register and offset */
-#if __riscv_xlen == 32
-	pmpcfg_csr   = CSR_PMPCFG0 + (n >> 2);
-	pmpcfg_shift = (n & 3) << 3;
-#elif __riscv_xlen == 64
-	pmpcfg_csr   = (CSR_PMPCFG0 + (n >> 2)) & ~1;
-	pmpcfg_shift = (n & 7) << 3;
-#else
-# error "Unexpected __riscv_xlen"
-#endif
-	pmpaddr_csr = CSR_PMPADDR0 + n;
-
 	/* encode PMP config */
 	prot &= ~PMP_A;
 	prot |= (log2len == PMP_SHIFT) ? PMP_A_NA4 : PMP_A_NAPOT;
-	pmp.cfg = prot;
+	pmp->cfg = prot;
 
 	/* encode PMP address */
 	if (log2len == PMP_SHIFT) {
-		pmp.addr = (addr >> PMP_SHIFT);
+		pmp->addr = (addr >> PMP_SHIFT);
 	} else {
 		if (log2len == __riscv_xlen) {
-			pmp.addr = -1UL;
+			pmp->addr = -1UL;
 		} else {
+			unsigned long addrmask;
 			addrmask = (1UL << (log2len - PMP_SHIFT)) - 1;
-			pmp.addr = ((addr >> PMP_SHIFT) & ~addrmask);
-			pmp.addr |= (addrmask >> 1);
+			pmp->addr = ((addr >> PMP_SHIFT) & ~addrmask);
+			pmp->addr |= (addrmask >> 1);
 		}
 	}
 
-	/* write csrs */
-	csr_write_num(pmpaddr_csr, pmp.addr);
-	cfgmask = ~(0xffUL << pmpcfg_shift);
-	pmpcfg  = (csr_read_num(pmpcfg_csr) & cfgmask);
-	pmpcfg |= (((unsigned long)pmp.cfg << pmpcfg_shift) & ~cfgmask);
-	csr_write_num(pmpcfg_csr, pmpcfg);
-
-	return 0;
+	return SBI_OK;
 }
 
-int pmp_get(unsigned int n, unsigned long *prot_out, unsigned long *addr_out,
-	    unsigned long *log2len)
+int pmp_set(unsigned int n, unsigned long prot, unsigned long addr,
+	    unsigned long log2len)
 {
 	int pmpcfg_csr, pmpcfg_shift, pmpaddr_csr;
-	unsigned long cfgmask, prot;
-	unsigned long t1, addr, len;
+	unsigned long cfgmask, pmpcfg;
 	pmp_t pmp;
+	int rc;
 
 	/* check parameters */
-	if (n >= PMP_COUNT || !prot_out || !addr_out || !log2len)
+	if (n >= PMP_COUNT)
 		return SBI_EINVAL;
-	*prot_out = *addr_out = *log2len = 0;
+
+	rc = pmp_encode(&pmp, prot, addr, log2len);
+	if (rc)
+		return rc;
 
 	/* calculate PMP register and offset */
 #if __riscv_xlen == 32
@@ -413,16 +393,33 @@ int pmp_get(unsigned int n, unsigned long *prot_out, unsigned long *addr_out,
 #endif
 	pmpaddr_csr = CSR_PMPADDR0 + n;
 
-	cfgmask = (0xffUL << pmpcfg_shift);
-	pmp.cfg = (csr_read_num(pmpcfg_csr) & cfgmask) >> pmpcfg_shift;
-	pmp.addr = csr_read_num(pmpaddr_csr);
+	/* write csrs */
+	csr_write_num(pmpaddr_csr, pmp.addr);
+	cfgmask = ~(0xffUL << pmpcfg_shift);
+	pmpcfg  = (csr_read_num(pmpcfg_csr) & cfgmask);
+	pmpcfg |= (((unsigned long)pmp.cfg << pmpcfg_shift) & ~cfgmask);
+	csr_write_num(pmpcfg_csr, pmpcfg);
+
+	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;
+	prot = pmp->cfg;
 
 	/* decode PMP address */
 	if ((prot & PMP_A) == PMP_A_NAPOT) {
-		addr = pmp.addr;
+		addr = pmp->addr;
 		if (addr == -1UL) {
 			addr	= 0;
 			len	= __riscv_xlen;
@@ -432,7 +429,7 @@ int pmp_get(unsigned int n, unsigned long *prot_out, unsigned long *addr_out,
 			len	= (t1 + PMP_SHIFT + 1);
 		}
 	} else {
-		addr	= pmp.addr << PMP_SHIFT;
+		addr	= pmp->addr << PMP_SHIFT;
 		len	= PMP_SHIFT;
 	}
 
@@ -441,5 +438,35 @@ int pmp_get(unsigned int n, unsigned long *prot_out, unsigned long *addr_out,
 	*addr_out    = addr;
 	*log2len     = len;
 
-	return 0;
+	return SBI_OK;
+}
+
+int pmp_get(unsigned int n, unsigned long *prot_out, unsigned long *addr_out,
+	    unsigned long *log2len)
+{
+	int pmpcfg_csr, pmpcfg_shift, pmpaddr_csr;
+	unsigned long cfgmask;
+	pmp_t pmp;
+
+	/* check parameters */
+	if (n >= PMP_COUNT)
+		return SBI_EINVAL;
+
+	/* calculate PMP register and offset */
+#if __riscv_xlen == 32
+	pmpcfg_csr   = CSR_PMPCFG0 + (n >> 2);
+	pmpcfg_shift = (n & 3) << 3;
+#elif __riscv_xlen == 64
+	pmpcfg_csr   = (CSR_PMPCFG0 + (n >> 2)) & ~1;
+	pmpcfg_shift = (n & 7) << 3;
+#else
+# error "Unexpected __riscv_xlen"
+#endif
+	pmpaddr_csr = CSR_PMPADDR0 + n;
+
+	cfgmask = (0xffUL << pmpcfg_shift);
+	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);
 }