firewire: core: add CSR abdicate support

Implement the abdicate bit, which is required for bus manager
capable nodes and tested by the Base 1394 Test Suite.

Finally, something to do at a command reset!  :-)

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

5 files changed, 18 insertions, 3 deletions

diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index d0f15c2f1e1d..7c4cf6cfa746 100644
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -260,7 +260,8 @@ static void fw_card_bm_work(struct work_struct *work)
 
         grace = time_after(jiffies, card->reset_jiffies + DIV_ROUND_UP(HZ, 8));
 
-        if (is_next_generation(generation, card->bm_generation) ||
+        if ((is_next_generation(generation, card->bm_generation) &&
+             !card->bm_abdicate) ||
             (card->bm_generation != generation && grace)) {
                 /*
                  * This first step is to figure out who is IRM and
diff --git a/drivers/firewire/core-topology.c b/drivers/firewire/core-topology.c
index 93ec64cdeef7..ca3c65318165 100644
--- a/drivers/firewire/core-topology.c
+++ b/drivers/firewire/core-topology.c
@@ -552,6 +552,8 @@ void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation,
         smp_wmb();
         card->generation = generation;
         card->reset_jiffies = jiffies;
+        card->bm_abdicate = card->csr_abdicate;
+        card->csr_abdicate = false;
         fw_schedule_bm_work(card, 0);
 
         local_node = build_tree(card, self_ids, self_id_count);
diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c
index e0c6cce894cf..85a54da243e2 100644
--- a/drivers/firewire/core-transaction.c
+++ b/drivers/firewire/core-transaction.c
@@ -1008,6 +1008,10 @@ static u32 read_state_register(struct fw_card *card)
         /* Bit 8 (cmstr): */
         value |= card->driver->read_csr_reg(card, CSR_STATE_CLEAR);
 
+        /* Bit 10 (abdicate): */
+        if (card->csr_abdicate)
+                value |= CSR_STATE_BIT_ABDICATE;
+
         return value;
 }
 
@@ -1041,6 +1045,8 @@ static void handle_registers(struct fw_card *card, struct fw_request *request,
                 } else if (tcode == TCODE_WRITE_QUADLET_REQUEST) {
                         card->driver->write_csr_reg(card, CSR_STATE_CLEAR,
                                                     be32_to_cpu(*data));
+                        if (*data & cpu_to_be32(CSR_STATE_BIT_ABDICATE))
+                                card->csr_abdicate = false;
                 } else {
                         rcode = RCODE_TYPE_ERROR;
                 }
@@ -1052,7 +1058,8 @@ static void handle_registers(struct fw_card *card, struct fw_request *request,
                 } else if (tcode == TCODE_WRITE_QUADLET_REQUEST) {
                         card->driver->write_csr_reg(card, CSR_STATE_SET,
                                                     be32_to_cpu(*data));
-                        /* FIXME: implement abdicate */
+                        if (*data & cpu_to_be32(CSR_STATE_BIT_ABDICATE))
+                                card->csr_abdicate = true;
                 } else {
                         rcode = RCODE_TYPE_ERROR;
                 }
@@ -1070,7 +1077,9 @@ static void handle_registers(struct fw_card *card, struct fw_request *request,
                 break;
 
         case CSR_RESET_START:
-                if (tcode != TCODE_WRITE_QUADLET_REQUEST)
+                if (tcode == TCODE_WRITE_QUADLET_REQUEST)
+                        card->csr_abdicate = false;
+                else
                         rcode = RCODE_TYPE_ERROR;
                 break;
 
diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
index aaecdd1c1767..a9ace1f8dc3f 100644
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -41,6 +41,7 @@ struct fw_packet;
 #define FEATURE_PRIORITY_BUDGET         0x01
 
 #define CSR_STATE_BIT_CMSTR     (1 << 8)
+#define CSR_STATE_BIT_ABDICATE  (1 << 10)
 
 struct fw_card_driver {
         /*
diff --git a/include/linux/firewire.h b/include/linux/firewire.h
index f1160e831dad..4d22643215ef 100644
--- a/include/linux/firewire.h
+++ b/include/linux/firewire.h
@@ -119,6 +119,8 @@ struct fw_card {
         int bm_retries;
         int bm_generation;
         __be32 bm_transaction_data[2];
+        bool bm_abdicate; /* value of csr_abdicate before last bus reset */
+        bool csr_abdicate; /* visible in CSR STATE_CLEAR/SET registers */
 
         bool broadcast_channel_allocated;
         u32 broadcast_channel;