[PATCH 2/2] lib: sbi: Use a linked list to track domains

[Samuel Holland]

This removes the compile-time limit on the number of domains. It also
reduces firmware size by about 200 bytes by removing the lookup table.

Signed-off-by: Samuel Holland <samuel.holland at sifive.com>
---

 include/sbi/sbi_domain.h     | 18 +++++++-----------
 lib/sbi/sbi_domain.c         | 30 +++++++++---------------------
 lib/sbi/sbi_domain_context.c |  6 +++---
 3 files changed, 19 insertions(+), 35 deletions(-)

diff --git a/include/sbi/sbi_domain.h b/include/sbi/sbi_domain.h
index 34ebd39d..313ae156 100644
--- a/include/sbi/sbi_domain.h
+++ b/include/sbi/sbi_domain.h
@@ -11,6 +11,7 @@
 #define __SBI_DOMAIN_H__
 
 #include <sbi/riscv_locks.h>
+#include <sbi/sbi_list.h>
 #include <sbi/sbi_types.h>
 #include <sbi/sbi_hartmask.h>
 #include <sbi/sbi_domain_context.h>
@@ -158,11 +159,10 @@ struct sbi_domain_memregion {
 	unsigned long flags;
 };
 
-/** Maximum number of domains */
-#define SBI_DOMAIN_MAX_INDEX			32
-
 /** Representation of OpenSBI domain */
 struct sbi_domain {
+	/** Node in linked list of domains */
+	struct sbi_dlist node;
 	/** Logical index of this domain */
 	u32 index;
 	/** HARTs assigned to this domain */
@@ -206,16 +206,12 @@ void sbi_update_hartindex_to_domain(u32 hartindex, struct sbi_domain *dom);
 #define sbi_domain_thishart_ptr() \
 	sbi_hartindex_to_domain(sbi_hartid_to_hartindex(current_hartid()))
 
-/** Index to domain table */
-extern struct sbi_domain *domidx_to_domain_table[];
-
-/** Get pointer to sbi_domain from index */
-#define sbi_index_to_domain(__index) \
-	domidx_to_domain_table[__index]
+/** Head of linked list of domains */
+extern struct sbi_dlist domain_list;
 
 /** Iterate over each domain */
-#define sbi_domain_for_each(__i, __d) \
-	for ((__i) = 0; ((__d) = sbi_index_to_domain(__i)); (__i)++)
+#define sbi_domain_for_each(__d) \
+	sbi_list_for_each_entry(__d, &domain_list, node)
 
 /** Iterate over each memory region of a domain */
 #define sbi_domain_for_each_memregion(__d, __r) \
diff --git a/lib/sbi/sbi_domain.c b/lib/sbi/sbi_domain.c
index 374ac36b..7198e27e 100644
--- a/lib/sbi/sbi_domain.c
+++ b/lib/sbi/sbi_domain.c
@@ -13,16 +13,14 @@
 #include <sbi/sbi_hartmask.h>
 #include <sbi/sbi_heap.h>
 #include <sbi/sbi_hsm.h>
+#include <sbi/sbi_list.h>
 #include <sbi/sbi_math.h>
 #include <sbi/sbi_platform.h>
 #include <sbi/sbi_scratch.h>
 #include <sbi/sbi_string.h>
 
-/*
- * We allocate an extra element because sbi_domain_for_each() expects
- * the array to be null-terminated.
- */
-struct sbi_domain *domidx_to_domain_table[SBI_DOMAIN_MAX_INDEX + 1] = { 0 };
+SBI_LIST_HEAD(domain_list);
+
 static u32 domain_count = 0;
 static bool domain_finalized = false;
 
@@ -519,10 +517,9 @@ void sbi_domain_dump(const struct sbi_domain *dom, const char *suffix)
 
 void sbi_domain_dump_all(const char *suffix)
 {
-	u32 i;
 	const struct sbi_domain *dom;
 
-	sbi_domain_for_each(i, dom) {
+	sbi_domain_for_each(dom) {
 		sbi_domain_dump(dom, suffix);
 		sbi_printf("\n");
 	}
@@ -541,21 +538,11 @@ int sbi_domain_register(struct sbi_domain *dom,
 		return SBI_EINVAL;
 
 	/* Check if domain already discovered */
-	sbi_domain_for_each(i, tdom) {
+	sbi_domain_for_each(tdom) {
 		if (tdom == dom)
 			return SBI_EALREADY;
 	}
 
-	/*
-	 * Ensure that we have room for Domain Index to
-	 * HART ID mapping
-	 */
-	if (SBI_DOMAIN_MAX_INDEX <= domain_count) {
-		sbi_printf("%s: No room for %s\n",
-			   __func__, dom->name);
-		return SBI_ENOSPC;
-	}
-
 	/* Sanitize discovered domain */
 	rc = sanitize_domain(dom);
 	if (rc) {
@@ -565,9 +552,10 @@ int sbi_domain_register(struct sbi_domain *dom,
 		return rc;
 	}
 
+	sbi_list_add_tail(&dom->node, &domain_list);
+
 	/* Assign index to domain */
 	dom->index = domain_count++;
-	domidx_to_domain_table[dom->index] = dom;
 
 	/* Initialize spinlock for dom->assigned_harts */
 	SPIN_LOCK_INIT(dom->assigned_harts_lock);
@@ -692,7 +680,7 @@ int sbi_domain_root_add_memrange(unsigned long addr, unsigned long size,
 int sbi_domain_finalize(struct sbi_scratch *scratch, u32 cold_hartid)
 {
 	int rc;
-	u32 i, dhart;
+	u32 dhart;
 	struct sbi_domain *dom;
 	const struct sbi_platform *plat = sbi_platform_ptr(scratch);
 
@@ -705,7 +693,7 @@ int sbi_domain_finalize(struct sbi_scratch *scratch, u32 cold_hartid)
 	}
 
 	/* Startup boot HART of domains */
-	sbi_domain_for_each(i, dom) {
+	sbi_domain_for_each(dom) {
 		/* Domain boot HART index */
 		dhart = sbi_hartid_to_hartindex(dom->boot_hartid);
 
diff --git a/lib/sbi/sbi_domain_context.c b/lib/sbi/sbi_domain_context.c
index 49a2f769..1432e3a8 100755
--- a/lib/sbi/sbi_domain_context.c
+++ b/lib/sbi/sbi_domain_context.c
@@ -107,7 +107,7 @@ int sbi_domain_context_enter(struct sbi_domain *dom)
 
 int sbi_domain_context_exit(void)
 {
-	u32 i, hartindex = sbi_hartid_to_hartindex(current_hartid());
+	u32 hartindex = sbi_hartid_to_hartindex(current_hartid());
 	struct sbi_domain *dom;
 	struct sbi_context *ctx = sbi_domain_context_thishart_ptr();
 	struct sbi_context *dom_ctx, *tmp;
@@ -118,7 +118,7 @@ int sbi_domain_context_exit(void)
 	 * its context on the current hart if valid.
 	 */
 	if (!ctx) {
-		sbi_domain_for_each(i, dom) {
+		sbi_domain_for_each(dom) {
 			if (!sbi_hartmask_test_hartindex(hartindex,
 							 dom->possible_harts))
 				continue;
@@ -140,7 +140,7 @@ int sbi_domain_context_exit(void)
 	/* If no previous caller context */
 	if (!dom_ctx) {
 		/* Try to find next uninitialized user-defined domain's context */
-		sbi_domain_for_each(i, dom) {
+		sbi_domain_for_each(dom) {
 			if (dom == &root || dom == sbi_domain_thishart_ptr())
 				continue;
 
-- 
2.45.1