[RFC PATCH] lib: sbi_hart: Store PMP granularity as log base 2

[Samuel Holland]

This minimizes the need to call log2roundup() to recover the log value.

Signed-off-by: Samuel Holland <samuel.holland at sifive.com>
---
This actually ends up with a net increase in code size, so it's probably
not worth merging. I'm sending the patch for completeness.

 include/sbi/sbi_hart.h |  4 ++--
 lib/sbi/sbi_hart.c     | 10 +++++-----
 lib/sbi/sbi_init.c     |  2 +-
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
index 6ee49ff..cbcac78 100644
--- a/include/sbi/sbi_hart.h
+++ b/include/sbi/sbi_hart.h
@@ -71,7 +71,7 @@ struct sbi_hart_features {
 	unsigned long extensions[BITS_TO_LONGS(SBI_HART_EXT_MAX)];
 	unsigned int pmp_count;
 	unsigned int pmp_addr_bits;
-	unsigned long pmp_gran;
+	unsigned int pmp_gran_log2;
 	unsigned int mhpm_mask;
 	unsigned int mhpm_bits;
 };
@@ -91,7 +91,7 @@ unsigned int sbi_hart_mhpm_mask(struct sbi_scratch *scratch);
 void sbi_hart_delegation_dump(struct sbi_scratch *scratch,
 			      const char *prefix, const char *suffix);
 unsigned int sbi_hart_pmp_count(struct sbi_scratch *scratch);
-unsigned long sbi_hart_pmp_granularity(struct sbi_scratch *scratch);
+unsigned int sbi_hart_pmp_gran_log2(struct sbi_scratch *scratch);
 unsigned int sbi_hart_pmp_addrbits(struct sbi_scratch *scratch);
 unsigned int sbi_hart_mhpm_bits(struct sbi_scratch *scratch);
 int sbi_hart_pmp_configure(struct sbi_scratch *scratch);
diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
index bf8792a..5141160 100644
--- a/lib/sbi/sbi_hart.c
+++ b/lib/sbi/sbi_hart.c
@@ -267,12 +267,12 @@ unsigned int sbi_hart_pmp_count(struct sbi_scratch *scratch)
 	return hfeatures->pmp_count;
 }
 
-unsigned long sbi_hart_pmp_granularity(struct sbi_scratch *scratch)
+unsigned int sbi_hart_pmp_gran_log2(struct sbi_scratch *scratch)
 {
 	struct sbi_hart_features *hfeatures =
 			sbi_scratch_offset_ptr(scratch, hart_features_offset);
 
-	return hfeatures->pmp_gran;
+	return hfeatures->pmp_gran_log2;
 }
 
 unsigned int sbi_hart_pmp_addrbits(struct sbi_scratch *scratch)
@@ -508,7 +508,7 @@ int sbi_hart_map_saddr(unsigned long addr, unsigned long size)
 	if (is_pmp_entry_mapped(SBI_SMEPMP_RESV_ENTRY))
 		return SBI_ENOSPC;
 
-	for (order = log2roundup(MAX(sbi_hart_pmp_granularity(scratch), size));
+	for (order = MAX(sbi_hart_pmp_gran_log2(scratch), log2roundup(size));
 	     order <= __riscv_xlen; order++) {
 		if (order < __riscv_xlen) {
 			base = addr & ~((1UL << order) - 1UL);
@@ -547,7 +547,7 @@ int sbi_hart_pmp_configure(struct sbi_scratch *scratch)
 	if (!pmp_count)
 		return 0;
 
-	pmp_gran_log2 = log2roundup(sbi_hart_pmp_granularity(scratch));
+	pmp_gran_log2 = sbi_hart_pmp_gran_log2(scratch);
 	pmp_bits = sbi_hart_pmp_addrbits(scratch) - 1;
 	pmp_addr_max = (1UL << pmp_bits) | ((1UL << pmp_bits) - 1);
 
@@ -871,7 +871,7 @@ static int hart_detect_features(struct sbi_scratch *scratch)
 	 */
 	val = hart_pmp_get_allowed_addr();
 	if (val) {
-		hfeatures->pmp_gran =  1 << (sbi_ffs(val) + 2);
+		hfeatures->pmp_gran_log2 = sbi_ffs(val) + 2;
 		hfeatures->pmp_addr_bits = sbi_fls(val) + 1;
 		/* Detect number of PMP regions. At least PMPADDR0 should be implemented*/
 		__check_csr_64(CSR_PMPADDR0, 0, val, pmp_count, __pmp_skip);
diff --git a/lib/sbi/sbi_init.c b/lib/sbi/sbi_init.c
index e723553..bfb8300 100644
--- a/lib/sbi/sbi_init.c
+++ b/lib/sbi/sbi_init.c
@@ -177,7 +177,7 @@ static void sbi_boot_print_hart(struct sbi_scratch *scratch, u32 hartid)
 	sbi_printf("Boot HART PMP Count       : %d\n",
 		   sbi_hart_pmp_count(scratch));
 	sbi_printf("Boot HART PMP Granularity : %lu\n",
-		   sbi_hart_pmp_granularity(scratch));
+		   1UL << sbi_hart_pmp_gran_log2(scratch));
 	sbi_printf("Boot HART PMP Address Bits: %d\n",
 		   sbi_hart_pmp_addrbits(scratch));
 	sbi_printf("Boot HART MHPM Info       : %lu (0x%08x)\n",
-- 
2.42.0