On Tue, Nov 28, 2017 at 04:55:35PM -0800, David Daney wrote:

Maybe put that on a separate line like below.

presumably this could be a u32 *, avoid the cast to u64, and still work
just fine below.

+
+	__asm__ __volatile__(
+		".set noreorder\n"
+		"1: ll   %[tmp], 0(%[addr])\n"
+		"   bnez %[tmp], 1b\n"
+		"   li   %[tmp], 1\n"

I believe the convention for .S files is for instructions in branch
delay slots to be indented an additional space for readability. Maybe
that would be worthwhile here.

+		"   sc   %[tmp], 0(%[addr])\n"
+		"   beqz %[tmp], 1b\n"
+		"   nop\n"

and here also.

+		".set reorder\n" :

nit: strictly speaking there's no need for \n on the last line.

+		[tmp] "=&r"(tmp) :
+		[addr] "r"(lock) :
+		"memory");

minor style thing: its far more common to have : at the beginning of the
line rather than the end.

+}
+
+static void res_mgr_unlock(void)
+{
+	u64 lock = (u64)&res_mgr_info->rlock;

same again

+
+	/* Wait until all resource operations finish before unlocking. */
+	mb();
+	__asm__ __volatile__(
+		"sw $0, 0(%[addr])\n" : :
+		[addr] "r"(lock) :
+		"memory");
+
+	/* Force a write buffer flush. */
+	mb();
+}
+
+static int res_mgr_find_resource(struct global_resource_tag tag)
+{
+	struct global_resource_entry *res_entry;
+	int i;
+
+	for (i = 0; i < res_mgr_info->entry_cnt; i++) {
+		res_entry = &res_mgr_info->resource_entry[i];
+		if (res_entry->tag.lo == tag.lo && res_entry->tag.hi == tag.hi)
+			return i;
+	}
+	return -1;
+}
+
+/**
+ * res_mgr_create_resource - Create a resource.
+ * @tag: Identifies the resource.
+ * @inst_cnt: Number of resource instances to create.
+ *
+ * Returns 0 if the source was created successfully.
+ * Returns <0 for error codes.

Only -1 seems to be returned. Is it worth returning some standard Linux
error codes instead?

+ */
+int res_mgr_create_resource(struct global_resource_tag tag, int inst_cnt)
+{
+	struct global_resource_entry *res_entry;
+	u64 size;
+	u64 *res_addr;
+	int res_index, i, rc = 0;
+
+	res_mgr_lock();
+
+	/* Make sure resource doesn't already exist. */
+	res_index = res_mgr_find_resource(tag);
+	if (res_index >= 0) {
+		rc = -1;
+		goto err;
+	}
+
+	if (res_mgr_info->entry_cnt >= MAX_RESOURCES) {
+		pr_err("Resource max limit reached, not created\n");
+		rc = -1;
+		goto err;
+	}
+
+	/*
+	 * Each instance is kept in an array of u64s. The first array element
+	 * holds the number of allocated instances.
+	 */
+	size = sizeof(u64) * (inst_cnt + 1);
+	res_addr = cvmx_bootmem_alloc_range(size, CVMX_CACHE_LINE_SIZE, 0, 0);
+	if (!res_addr) {
+		pr_err("Failed to allocate resource. not created\n");
+		rc = -1;
+		goto err;
+	}
+
+	/* Initialize the newly created resource. */
+	*res_addr = inst_cnt;
+	for (i = 1; i < inst_cnt + 1; i++)

or "i <= inst_cnt"?

+		*(res_addr + i) = INST_AVAILABLE;

Nit: IMO res_addr[i] is marginally more readable

+
+	res_index = res_mgr_info->entry_cnt;
+	res_entry = &res_mgr_info->resource_entry[res_index];
+	res_entry->tag.lo = tag.lo;
+	res_entry->tag.hi = tag.hi;

or res_entry->tag = tag;?

+	res_entry->phys_addr = virt_to_phys(res_addr);
+	res_entry->size = size;
+	res_mgr_info->entry_cnt++;
+
+err:
+	res_mgr_unlock();
+
+	return rc;
+}
+EXPORT_SYMBOL(res_mgr_create_resource);
+
+/**
+ * res_mgr_alloc_range - Allocate a range of resource instances.

I don't know how strict kerndoc is on this, but I think it should be
res_mgr_alloc_range() here. Same elsewhere.

+ * @tag: Identifies the resource.
+ * @req_inst: Requested start of instance range to allocate.
+ *	      Range instances are guaranteed to be sequential
+ *	      (-1 for don't care).
+ * @req_cnt: Number of instances to allocate.
+ * @use_last_avail: Set to request the last available instance.
+ * @inst: Updated with the allocated instances.
+ *
+ * Returns 0 if the source was created successfully.
+ * Returns <0 for error codes.
+ */
+int res_mgr_alloc_range(struct global_resource_tag tag, int req_inst,
+			int req_cnt, bool use_last_avail, int *inst)
+{
+	struct global_resource_entry *res_entry;
+	int res_index;
+	u64 *res_addr;
+	u64 inst_cnt;
+	int alloc_cnt, i, rc = -1;
+
+	/* Start with no instances allocated. */
+	for (i = 0; i < req_cnt; i++)
+		inst[i] = INST_AVAILABLE;
+
+	res_mgr_lock();
+
+	/* Find the resource. */
+	res_index = res_mgr_find_resource(tag);
+	if (res_index < 0) {
+		pr_err("Resource not found, can't allocate instance\n");
+		goto err;
+	}
+
+	/* Get resource data. */
+	res_entry = &res_mgr_info->resource_entry[res_index];
+	res_addr = phys_to_virt(res_entry->phys_addr);
+	inst_cnt = *res_addr;
+
+	/* Allocate the requested instances. */
+	if (req_inst >= 0) {
+		/* Specific instance range requested. */
+		if (req_inst + req_cnt >= inst_cnt) {
+			pr_err("Requested instance out of range\n");
+			goto err;
+		}
+
+		for (i = 0; i < req_cnt; i++) {
+			if (*(res_addr + req_inst + 1 + i) == INST_AVAILABLE)
+				inst[i] = req_inst + i;
+			else {

braces on all branches if on any.

+				inst[0] = INST_AVAILABLE;
+				break;
+			}
+		}
+	} else if (use_last_avail) {
+		/* Last available instance requested. */
+		alloc_cnt = 0;
+		for (i = inst_cnt; i > 0; i--) {
+			if (*(res_addr + i) == INST_AVAILABLE) {
+				/*
+				 * Instance off by 1 (first element holds the
+				 * count).
+				 */
+				inst[alloc_cnt] = i - 1;
+
+				alloc_cnt++;
+				if (alloc_cnt == req_cnt)
+					break;
+			}
+		}
+
+		if (i == 0)
+			inst[0] = INST_AVAILABLE;
+	} else {
+		/* Next available instance requested. */
+		alloc_cnt = 0;
+		for (i = 1; i <= inst_cnt; i++) {
+			if (*(res_addr + i) == INST_AVAILABLE) {
+				/*
+				 * Instance off by 1 (first element holds the
+				 * count).
+				 */
+				inst[alloc_cnt] = i - 1;
+
+				alloc_cnt++;
+				if (alloc_cnt == req_cnt)
+					break;
+			}
+		}
+
+		if (i > inst_cnt)
+			inst[0] = INST_AVAILABLE;
+	}
+
+	if (inst[0] != INST_AVAILABLE) {
+		for (i = 0; i < req_cnt; i++)
+			*(res_addr + inst[i] + 1) = OWNER;
+		rc = 0;
+	}
+
+err:
+	res_mgr_unlock();
+
+	return rc;
+}
+EXPORT_SYMBOL(res_mgr_alloc_range);
+
+/**
+ * res_mgr_alloc - Allocate a resource instance.
+ * @tag: Identifies the resource.
+ * @req_inst: Requested instance to allocate (-1 for don't care).
+ * @use_last_avail: Set to request the last available instance.
+ *
+ * Returns: Allocated resource instance if successful.
+ * Returns <0 for error codes.
+ */
+int res_mgr_alloc(struct global_resource_tag tag, int req_inst, bool use_last_avail)
+{
+	int inst, rc;
+
+	rc = res_mgr_alloc_range(tag, req_inst, 1, use_last_avail, &inst);
+	if (!rc)
+		return inst;
+	return rc;
+}
+EXPORT_SYMBOL(res_mgr_alloc);
+
+/**
+ * res_mgr_free_range - Free a resource instance range.
+ * @tag: Identifies the resource.
+ * @req_inst: Requested instance to free.

the parameter is called inst.

Other than these minor / style comments, it doesn't look unreasonable to
me.

Cheers
James