[PATCH 1/5] firewire: ohci: use in_range() macro to detect CSR address ranges

[Takashi Sakamoto]

The current implementation handles asynchronous packets sent to the two
CSR address ranges on the local node specially. To decide whether a packet
is destined for either range, the destination offset needs to be checked
according to the IEEE 1394 and 1394 OHCI specifications.

The current implementation uses both conditional and switch statements to
check the offset, which makes the range checks difficult to reuse.

Add two helper functions for the range checks using the in_range() macro.

Signed-off-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>
---
 drivers/firewire/ohci.c | 33 ++++++++++++++++++---------------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 7d797755bbd6..c8cb7bdcb4ed 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -1534,35 +1534,38 @@ static void handle_local_lock(struct fw_ohci *ohci,
 	fw_core_handle_response(&ohci->card, &response);
 }
 
+static bool in_config_rom_csr_registers(u64 offset)
+{
+	return in_range(offset, CSR_CONFIG_ROM, CONFIG_ROM_SIZE);
+}
+
+// 5.5.1 Bus Management CSR Registers.
+static bool in_bus_management_csr_registers(u64 offset)
+{
+	// 0x22c = CSR_MAINT_CONTROL following to CSR_CHANNELS_AVAILABLE_LO.
+	return in_range(offset, CSR_BUS_MANAGER_ID, 0x22c - CSR_BUS_MANAGER_ID);
+}
+
 static void handle_local_request(struct at_context *ctx, struct fw_packet *packet)
 {
 	struct fw_ohci *ohci = ctx->context.ohci;
-	u64 offset, csr;
 
 	if (ctx == &ohci->at_request_ctx) {
 		packet->ack = ACK_PENDING;
 		packet->callback(packet, &ohci->card, packet->ack);
 	}
 
-	offset = async_header_get_offset(packet->header);
-	csr = offset - CSR_REGISTER_BASE;
+	u64 csr_offset = async_header_get_offset(packet->header) - CSR_REGISTER_BASE;
 
-	/* Handle config rom reads. */
-	if (csr >= CSR_CONFIG_ROM && csr < CSR_CONFIG_ROM_END)
-		handle_local_rom(ohci, packet, csr);
-	else switch (csr) {
-	case CSR_BUS_MANAGER_ID:
-	case CSR_BANDWIDTH_AVAILABLE:
-	case CSR_CHANNELS_AVAILABLE_HI:
-	case CSR_CHANNELS_AVAILABLE_LO:
-		handle_local_lock(ohci, packet, csr);
-		break;
-	default:
+	if (in_config_rom_csr_registers(csr_offset)) {
+		handle_local_rom(ohci, packet, csr_offset);
+	} else if (in_bus_management_csr_registers(csr_offset)) {
+		handle_local_lock(ohci, packet, csr_offset);
+	} else {
 		if (ctx == &ohci->at_request_ctx)
 			fw_core_handle_request(&ohci->card, packet);
 		else
 			fw_core_handle_response(&ohci->card, packet);
-		break;
 	}
 
 	if (ctx == &ohci->at_response_ctx) {
-- 
2.53.0