From: Ben Cahill <ben.m.cahill@xxxxxxxxx>
Document 4965 Tx scheduler
Signed-off-by: Ben Cahill <ben.m.cahill@xxxxxxxxx>
Signed-off-by: Zhu Yi <yi.zhu@xxxxxxxxx>
---
drivers/net/wireless/iwlwifi/iwl-4965-hw.h | 268 ++++++++++++++++++++++++++-
drivers/net/wireless/iwlwifi/iwl-prph.h | 14 +-
drivers/net/wireless/iwlwifi/iwl4965-base.c | 2 +
3 files changed, 272 insertions(+), 12 deletions(-)
diff --git a/drivers/net/wireless/iwlwifi/iwl-4965-hw.h b/drivers/net/wireless/iwlwifi/iwl-4965-hw.h
index 85724e1..8a93ad5 100644
--- a/drivers/net/wireless/iwlwifi/iwl-4965-hw.h
+++ b/drivers/net/wireless/iwlwifi/iwl-4965-hw.h
@@ -1555,33 +1555,285 @@ enum {
/* RSCSR: defs used in normal mode */
#define FH_RSCSR_CHNL0_RBDCB_WPTR_MASK (0x00000FFF) /* bits 0-11 */
+/********************* START TX SCHEDULER *************************************/
+
+/**
+ * 4965 Tx Scheduler
+ *
+ * The Tx Scheduler selects the next frame to be transmitted, chosing TFDs
+ * (Transmit Frame Descriptors) from up to 16 circular Tx queues resident in
+ * host DRAM. It steers each frame's Tx command (which contains the frame
+ * data) into one of up to 7 prioritized Tx DMA FIFO channels within the
+ * device. A queue maps to only one (selectable by driver) Tx DMA channel,
+ * but one DMA channel may take input from several queues.
+ *
+ * Tx DMA channels have dedicated purposes. For 4965, they are used as follows:
+ *
+ * 0 -- EDCA BK (background) frames, lowest priority
+ * 1 -- EDCA BE (best effort) frames, normal priority
+ * 2 -- EDCA VI (video) frames, higher priority
+ * 3 -- EDCA VO (voice) and management frames, highest priority
+ * 4 -- Commands (e.g. RXON, etc.)
+ * 5 -- HCCA short frames
+ * 6 -- HCCA long frames
+ * 7 -- not used by driver (device-internal only)
+ *
+ * Driver should normally map queues 0-6 to Tx DMA/FIFO channels 0-6.
+ * In addition, driver can map queues 7-15 to Tx DMA/FIFO channels 0-3 to
+ * support 11n aggregation via EDCA DMA channels.
+ *
+ * The driver sets up each queue to work in one of two modes:
+ *
+ * 1) Scheduler-Ack, in which the scheduler automatically supports a
+ * block-ack (BA) window of up to 64 TFDs. In this mode, each queue
+ * contains TFDs for a unique combination of Recipient Address (RA)
+ * and Traffic Identifier (TID), that is, traffic of a given
+ * Quality-Of-Service (QOS) priority, destined for a single station.
+ *
+ * In scheduler-ack mode, the scheduler keeps track of the Tx status of
+ * each frame within the BA window, including whether it's been transmitted,
+ * and whether it's been acknowledged by the receiving station. The device
+ * automatically processes block-acks received from the receiving STA,
+ * and reschedules un-acked frames to be retransmitted (successful
+ * Tx completion may end up being out-of-order).
+ *
+ * The driver must maintain the queue's Byte Count table in host DRAM
+ * (struct iwl4965_sched_queue_byte_cnt_tbl) for this mode.
+ * This mode does not support fragmentation.
+ *
+ * 2) FIFO (a.k.a. non-Scheduler-ACK), in which each TFD is processed in order.
+ * The device may automatically retry Tx, but will retry only one frame
+ * at a time, until receiving ACK from receiving station, or reaching
+ * retry limit and giving up.
+ *
+ * The command queue (#4) must use this mode!
+ * This mode does not require use of the Byte Count table in host DRAM.
+ *
+ * Driver controls scheduler operation via 3 means:
+ * 1) Scheduler registers
+ * 2) Shared scheduler data base in internal 4956 SRAM
+ * 3) Shared data in host DRAM
+ *
+ * Initialization:
+ *
+ * When loading, driver should allocate memory for:
+ * 1) 16 TFD circular buffers, each with space for (typically) 256 TFDs.
+ * 2) 16 Byte Count circular buffers in 16 KBytes contiguous memory
+ * (1024 bytes for each queue).
+ *
+ * After receiving "Alive" response from uCode, driver must initialize
+ * the scheduler (especially for queue #4, the command queue, otherwise
+ * the driver can't issue commands!):
+ */
+
+/**
+ * Max Tx window size is the max number of contiguous TFDs that the scheduler
+ * can keep track of at one time when creating block-ack chains of frames.
+ * Note that "64" matches the number of ack bits in a block-ack packet.
+ * Driver should use SCD_WIN_SIZE and SCD_FRAME_LIMIT values to initialize
+ * SCD_CONTEXT_QUEUE_OFFSET(x) values.
+ */
#define SCD_WIN_SIZE 64
#define SCD_FRAME_LIMIT 64
-/* SRAM structures */
-#define SCD_CONTEXT_DATA_OFFSET 0x380
-#define SCD_TX_STTS_BITMAP_OFFSET 0x400
-#define SCD_TRANSLATE_TBL_OFFSET 0x500
-#define SCD_CONTEXT_QUEUE_OFFSET(x) (SCD_CONTEXT_DATA_OFFSET + ((x) * 8))
-#define SCD_TRANSLATE_TBL_OFFSET_QUEUE(x) \
- ((SCD_TRANSLATE_TBL_OFFSET + ((x) * 2)) & 0xfffffffc)
+/* SCD registers are internal, must be accessed via HBUS_TARG_PRPH regs */
+#define SCD_START_OFFSET 0xa02c00
+
+/*
+ * 4965 tells driver SRAM address for internal scheduler structs via this reg.
+ * Value is valid only after "Alive" response from uCode.
+ */
+#define SCD_SRAM_BASE_ADDR (SCD_START_OFFSET + 0x0)
+/*
+ * Driver may need to update queue-empty bits after changing queue's
+ * write and read pointers (indexes) during (re-)initialization (i.e. when
+ * scheduler is not tracking what's happening).
+ * Bit fields:
+ * 31-16: Write mask -- 1: update empty bit, 0: don't change empty bit
+ * 15-00: Empty state, one for each queue -- 1: empty, 0: non-empty
+ * NOTE: This register is not used by Linux driver.
+ */
+#define SCD_EMPTY_BITS (SCD_START_OFFSET + 0x4)
+
+/*
+ * Physical base address of array of byte count (BC) circular buffers (CBs).
+ * Each Tx queue has a BC CB in host DRAM to support Scheduler-ACK mode.
+ * This register points to BC CB for queue 0, must be on 1024-byte boundary.
+ * Others are spaced by 1024 bytes.
+ * Each BC CB is 2 bytes * (256 + 64) = 740 bytes, followed by 384 bytes pad.
+ * (Index into a queue's BC CB) = (index into queue's TFD CB) = (SSN & 0xff).
+ * Bit fields:
+ * 25-00: Byte Count CB physical address [35:10], must be 1024-byte aligned.
+ */
+#define SCD_DRAM_BASE_ADDR (SCD_START_OFFSET + 0x10)
+
+/*
+ * Enables any/all Tx DMA/FIFO channels.
+ * Scheduler generates requests for only the active channels.
+ * Set this to 0xff to enable all 8 channels (normal usage).
+ * Bit fields:
+ * 7- 0: Enable (1), disable (0), one bit for each channel 0-7
+ */
+#define SCD_TXFACT (SCD_START_OFFSET + 0x1c)
+
+/* Mask to enable contiguous Tx DMA/FIFO channels between "lo" and "hi". */
#define SCD_TXFACT_REG_TXFIFO_MASK(lo, hi) \
((1<<(hi))|((1<<(hi))-(1<<(lo))))
+/*
+ * Queue (x) Write Pointers (indexes, really!), one for each Tx queue.
+ * Initialized and updated by driver as new TFDs are added to queue.
+ * NOTE: If using Block Ack, index must correspond to frame's
+ * Start Sequence Number; index = (SSN & 0xff)
+ * NOTE: Alternative to HBUS_TARG_WRPTR, which is what Linux driver uses?
+ */
+#define SCD_QUEUE_WRPTR(x) (SCD_START_OFFSET + 0x24 + (x) * 4)
+
+/*
+ * Queue (x) Read Pointers (indexes, really!), one for each Tx queue.
+ * For FIFO mode, index indicates next frame to transmit.
+ * For Scheduler-ACK mode, index indicates first frame in Tx window.
+ * Initialized by driver, updated by scheduler.
+ */
+#define SCD_QUEUE_RDPTR(x) (SCD_START_OFFSET + 0x64 + (x) * 4)
+
+/*
+ * Select which queues work in chain mode (1) vs. not (0).
+ * Use chain mode to build chains of aggregated frames.
+ * Bit fields:
+ * 31-16: Reserved
+ * 15-00: Mode, one bit for each queue -- 1: Chain mode, 0: one-at-a-time
+ * NOTE: If driver sets up queue for chain mode, it should be also set up
+ * Scheduler-ACK mode as well, via SCD_QUEUE_STATUS_BITS(x).
+ */
+#define SCD_QUEUECHAIN_SEL (SCD_START_OFFSET + 0xd0)
+
+/*
+ * Select which queues interrupt driver when scheduler increments
+ * a queue's read pointer (index).
+ * Bit fields:
+ * 31-16: Reserved
+ * 15-00: Interrupt enable, one bit for each queue -- 1: enabled, 0: disabled
+ * NOTE: This functionality is apparently a no-op; driver relies on interrupts
+ * from Rx queue to read Tx command responses and update Tx queues.
+ */
+#define SCD_INTERRUPT_MASK (SCD_START_OFFSET + 0xe4)
+
+/*
+ * Queue search status registers. One for each queue.
+ * Sets up queue mode and assigns queue to Tx DMA channel.
+ * Bit fields:
+ * 19-10: Write mask/enable bits for bits 0-9
+ * 9: Driver should init to "0"
+ * 8: Scheduler-ACK mode (1), non-Scheduler-ACK (i.e. FIFO) mode (0).
+ * Driver should init to "1" for aggregation mode, or "0" otherwise.
+ * 7-6: Driver should init to "0"
+ * 5: Window Size Left; indicates whether scheduler can request
+ * another TFD, based on window size, etc. Driver should init
+ * this bit to "1" for aggregation mode, or "0" for non-agg.
+ * 4-1: Tx FIFO to use (range 0-7).
+ * 0: Queue is active (1), not active (0).
+ * Other bits should be written as "0"
+ *
+ * NOTE: If enabling Scheduler-ACK mode, chain mode should also be enabled
+ * via SCD_QUEUECHAIN_SEL.
+ */
+#define SCD_QUEUE_STATUS_BITS(x) (SCD_START_OFFSET + 0x104 + (x) * 4)
+
+/* Bit field positions */
#define SCD_QUEUE_STTS_REG_POS_ACTIVE (0)
#define SCD_QUEUE_STTS_REG_POS_TXF (1)
#define SCD_QUEUE_STTS_REG_POS_WSL (5)
#define SCD_QUEUE_STTS_REG_POS_SCD_ACK (8)
+
+/* Write masks */
#define SCD_QUEUE_STTS_REG_POS_SCD_ACT_EN (10)
#define SCD_QUEUE_STTS_REG_MSK (0x0007FC00)
+/**
+ * 4965 internal SRAM structures for scheduler, shared with driver ...
+ *
+ * Driver should clear and initialize the following areas after receiving
+ * "Alive" response from 4965 uCode, i.e. after initial
+ * uCode load, or after a uCode load done for error recovery:
+ *
+ * SCD_CONTEXT_DATA_OFFSET (size 128 bytes)
+ * SCD_TX_STTS_BITMAP_OFFSET (size 256 bytes)
+ * SCD_TRANSLATE_TBL_OFFSET (size 32 bytes)
+ *
+ * Driver accesses SRAM via HBUS_TARG_MEM_* registers.
+ * Driver reads base address of this scheduler area from SCD_SRAM_BASE_ADDR.
+ * All OFFSET values must be added to this base address.
+ */
+
+/*
+ * Queue context. One 8-byte entry for each of 16 queues.
+ *
+ * Driver should clear this entire area (size 0x80) to 0 after receiving
+ * "Alive" notification from uCode. Additionally, driver should init
+ * each queue's entry as follows:
+ *
+ * LS Dword bit fields:
+ * 0-06: Max Tx window size for Scheduler-ACK. Driver should init to 64.
+ *
+ * MS Dword bit fields:
+ * 16-22: Frame limit. Driver should init to 10 (0xa).
+ *
+ * Driver should init all other bits to 0.
+ *
+ * Init must be done after driver receives "Alive" response from 4965 uCode,
+ * and when setting up queue for aggregation.
+ */
+#define SCD_CONTEXT_DATA_OFFSET 0x380
+#define SCD_CONTEXT_QUEUE_OFFSET(x) (SCD_CONTEXT_DATA_OFFSET + ((x) * 8))
+
#define SCD_QUEUE_CTX_REG1_WIN_SIZE_POS (0)
#define SCD_QUEUE_CTX_REG1_WIN_SIZE_MSK (0x0000007F)
-
#define SCD_QUEUE_CTX_REG2_FRAME_LIMIT_POS (16)
#define SCD_QUEUE_CTX_REG2_FRAME_LIMIT_MSK (0x007F0000)
+/*
+ * Tx Status Bitmap
+ *
+ * Driver should clear this entire area (size 0x100) to 0 after receiving
+ * "Alive" notification from uCode. Area is used only by device itself;
+ * no other support (besides clearing) is required from driver.
+ */
+#define SCD_TX_STTS_BITMAP_OFFSET 0x400
+
+/*
+ * RAxTID to queue translation mapping.
+ *
+ * When queue is in Scheduler-ACK mode, frames placed in a that queue must be
+ * for only one combination of receiver address (RA) and traffic ID (TID), i.e.
+ * one QOS priority level destined for one station (for this wireless link,
+ * not final destination). The SCD_TRANSLATE_TABLE area provides 16 16-bit
+ * mappings, one for each of the 16 queues. If queue is not in Scheduler-ACK
+ * mode, the device ignores the mapping value.
+ *
+ * Bit fields, for each 16-bit map:
+ * 15-9: Reserved, set to 0
+ * 8-4: Index into device's station table for recipient station
+ * 3-0: Traffic ID (tid), range 0-15
+ *
+ * Driver should clear this entire area (size 32 bytes) to 0 after receiving
+ * "Alive" notification from uCode. To update a 16-bit map value, driver
+ * must read a dword-aligned value from device SRAM, replace the 16-bit map
+ * value of interest, and write the dword value back into device SRAM.
+ */
+#define SCD_TRANSLATE_TBL_OFFSET 0x500
+
+/* Find translation table dword to read/write for given queue */
+#define SCD_TRANSLATE_TBL_OFFSET_QUEUE(x) \
+ ((SCD_TRANSLATE_TBL_OFFSET + ((x) * 2)) & 0xfffffffc)
+
+#define SCD_TXFIFO_POS_TID (0)
+#define SCD_TXFIFO_POS_RA (4)
+#define SCD_QUEUE_RA_TID_MAP_RATID_MSK (0x01FF)
+
+/*********************** END TX SCHEDULER *************************************/
+
static inline u8 iwl4965_hw_get_rate(__le32 rate_n_flags)
{
return le32_to_cpu(rate_n_flags) & 0xFF;
diff --git a/drivers/net/wireless/iwlwifi/iwl-prph.h b/drivers/net/wireless/iwlwifi/iwl-prph.h
index 137947d..4ba1216 100644
--- a/drivers/net/wireless/iwlwifi/iwl-prph.h
+++ b/drivers/net/wireless/iwlwifi/iwl-prph.h
@@ -63,7 +63,10 @@
#ifndef __iwl_prph_h__
#define __iwl_prph_h__
-
+/*
+ * Registers in this file are internal, not PCI bus memory mapped.
+ * Driver accesses these via HBUS_TARG_PRPH_* registers.
+ */
#define PRPH_BASE (0x00000)
#define PRPH_END (0xFFFFF)
@@ -225,8 +228,8 @@
#define BSM_SRAM_LOWER_BOUND (PRPH_BASE + 0x3800)
#define BSM_SRAM_SIZE (1024) /* bytes */
-/* ALM SCD */
-/* SCD (Scheduler) */
+
+/* 3945 Tx scheduler registers */
#define ALM_SCD_BASE (PRPH_BASE + 0x2E00)
#define ALM_SCD_MODE_REG (ALM_SCD_BASE + 0x000)
#define ALM_SCD_ARASTAT_REG (ALM_SCD_BASE + 0x004)
@@ -236,7 +239,10 @@
#define ALM_SCD_SBYP_MODE_1_REG (ALM_SCD_BASE + 0x02C)
#define ALM_SCD_SBYP_MODE_2_REG (ALM_SCD_BASE + 0x030)
-/* 4965 SCD memory mapped registers */
+/*
+ * 4965 Tx Scheduler registers.
+ * Details are documented in iwl-4965-hw.h
+ */
#define KDR_SCD_BASE (PRPH_BASE + 0xa02c00)
#define KDR_SCD_SRAM_BASE_ADDR (KDR_SCD_BASE + 0x0)
diff --git a/drivers/net/wireless/iwlwifi/iwl4965-base.c b/drivers/net/wireless/iwlwifi/iwl4965-base.c
index ddeedf6..1a9dada 100644
--- a/drivers/net/wireless/iwlwifi/iwl4965-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl4965-base.c
@@ -202,6 +202,8 @@ static void iwl4965_print_hex_dump(int level, void *p, u32 len)
* The 4965 operates with up to 17 queues: One receive queue, one transmit
* queue (#4) for sending commands to the device firmware, and 15 other
* Tx queues that may be mapped to prioritized Tx DMA/FIFO channels.
+ *
+ * See more detailed info in iwl-4965-hw.h.
***************************************************/
static int iwl4965_queue_space(const struct iwl4965_queue *q)
--
1.5.2.2
---------------------------------------------------------------------
Intel Israel (74) Limited
This e-mail and any attachments may contain confidential material for
the sole use of the intended recipient(s). Any review or distribution
by others is strictly prohibited. If you are not the intended
recipient, please contact the sender and delete all copies.
-
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
