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iwlwifi: document shared Tx structures 

Document shared Tx structures

Signed-off-by: Ben Cahill <ben.m.cahill@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Ben Cahill 2007-11-29 11:10:06 +08:00 committed by David S. Miller
parent 483fd7e5ff
commit 5d5456fe50
1 changed files with 135 additions and 12 deletions
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147
drivers/net/wireless/iwlwifi/iwl-4965-hw.h
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@ -452,6 +452,13 @@ struct iwl4965_eeprom {
*/
#define CSR_HW_REV_WA_REG (CSR_BASE+0x22C)
/* Hardware interface configuration bits */
#define CSR_HW_IF_CONFIG_REG_BIT_KEDRON_R (0x00000010)
#define CSR_HW_IF_CONFIG_REG_MSK_BOARD_VER (0x00000C00)
#define CSR_HW_IF_CONFIG_REG_BIT_MAC_SI (0x00000100)
#define CSR_HW_IF_CONFIG_REG_BIT_RADIO_SI (0x00000200)
#define CSR_HW_IF_CONFIG_REG_BIT_EEPROM_OWN_SEM (0x00200000)
/* interrupt flags in INTA, set by uCode or hardware (e.g. dma),
* acknowledged (reset) by host writing "1" to flagged bits. */
#define CSR_INT_BIT_FH_RX (1<<31) /* Rx DMA, cmd responses, FH_INT[17:16] */
@ -1574,12 +1581,6 @@ enum {
#define SCD_QUEUE_CTX_REG2_FRAME_LIMIT_POS (16)
#define SCD_QUEUE_CTX_REG2_FRAME_LIMIT_MSK (0x007F0000)
#define CSR_HW_IF_CONFIG_REG_BIT_KEDRON_R (0x00000010)
#define CSR_HW_IF_CONFIG_REG_MSK_BOARD_VER (0x00000C00)
#define CSR_HW_IF_CONFIG_REG_BIT_MAC_SI (0x00000100)
#define CSR_HW_IF_CONFIG_REG_BIT_RADIO_SI (0x00000200)
#define CSR_HW_IF_CONFIG_REG_BIT_EEPROM_OWN_SEM (0x00200000)
static inline u8 iwl4965_hw_get_rate(__le32 rate_n_flags)
{
return le32_to_cpu(rate_n_flags) & 0xFF;
@ -1593,6 +1594,53 @@ static inline __le32 iwl4965_hw_set_rate_n_flags(u8 rate, u16 flags)
return cpu_to_le32(flags|(u16)rate);
}
/**
* Tx/Rx Queues
*
* Most communication between driver and 4965 is via queues of data buffers.
* For example, all commands that the driver issues to device's embedded
* controller (uCode) are via the command queue (one of the Tx queues). All
* uCode command responses/replies/notifications, including Rx frames, are
* conveyed from uCode to driver via the Rx queue.
*
* Most support for these queues, including handshake support, resides in
* structures in host DRAM, shared between the driver and the device. When
* allocating this memory, the driver must make sure that data written by
* the host CPU updates DRAM immediately (and does not get "stuck" in CPU's
* cache memory), so DRAM and cache are consistent, and the device can
* immediately see changes made by the driver.
*
* 4965 supports up to 16 DRAM-based Tx queues, and services these queues via
* up to 7 DMA channels (FIFOs). Each Tx queue is supported by a circular array
* in DRAM containing 256 Transmit Frame Descriptors (TFDs).
*/
#define IWL4965_MAX_WIN_SIZE 64
#define IWL4965_QUEUE_SIZE 256
#define IWL4965_NUM_FIFOS 7
#define IWL_MAX_NUM_QUEUES 16
/**
* struct iwl4965_tfd_frame_data
*
* Describes up to 2 buffers containing (contiguous) portions of a Tx frame.
* Each buffer must be on dword boundary.
* Up to 10 iwl_tfd_frame_data structures, describing up to 20 buffers,
* may be filled within a TFD (iwl_tfd_frame).
*
* Bit fields in tb1_addr:
* 31- 0: Tx buffer 1 address bits [31:0]
*
* Bit fields in val1:
* 31-16: Tx buffer 2 address bits [15:0]
* 15- 4: Tx buffer 1 length (bytes)
* 3- 0: Tx buffer 1 address bits [32:32]
*
* Bit fields in val2:
* 31-20: Tx buffer 2 length (bytes)
* 19- 0: Tx buffer 2 address bits [35:16]
*/
struct iwl4965_tfd_frame_data {
__le32 tb1_addr;
@ -1621,6 +1669,35 @@ struct iwl4965_tfd_frame_data {
#define IWL_tb2_len_SYM val2
} __attribute__ ((packed));
/**
* struct iwl4965_tfd_frame
*
* Transmit Frame Descriptor (TFD)
*
* 4965 supports up to 16 Tx queues resident in host DRAM.
* Each Tx queue uses a circular buffer of 256 TFDs stored in host DRAM.
* Both driver and device share these circular buffers, each of which must be
* contiguous 256 TFDs x 128 bytes-per-TFD = 32 KBytes for 4965.
*
* Driver must indicate the physical address of the base of each
* circular buffer via the 4965's FH_MEM_CBBC_QUEUE registers.
*
* Each TFD contains pointer/size information for up to 20 data buffers
* in host DRAM. These buffers collectively contain the (one) frame described
* by the TFD. Each buffer must be a single contiguous block of memory within
* itself, but buffers may be scattered in host DRAM. Each buffer has max size
* of (4K - 4). The 4965 concatenates all of a TFD's buffers into a single
* Tx frame, up to 8 KBytes in size.
*
* Bit fields in the control dword (val0):
* 31-30: # dwords (0-3) of padding required at end of frame for 16-byte bound
* 29: reserved
* 28-24: # Transmit Buffer Descriptors in TFD
* 23- 0: reserved
*
* A maximum of 255 (not 256!) TFDs may be on a queue waiting for Tx.
*/
struct iwl4965_tfd_frame {
__le32 val0;
/* __le32 rsvd1:24; */
@ -1634,11 +1711,16 @@ struct iwl4965_tfd_frame {
__le32 reserved;
} __attribute__ ((packed));
#define IWL4965_MAX_WIN_SIZE 64
#define IWL4965_QUEUE_SIZE 256
#define IWL4965_NUM_FIFOS 7
#define IWL_MAX_NUM_QUEUES 16
/**
* struct iwl4965_queue_byte_cnt_entry
*
* Byte Count Table Entry
*
* Bit fields:
* 15-12: reserved
* 11- 0: total to-be-transmitted byte count of frame (does not include command)
*/
struct iwl4965_queue_byte_cnt_entry {
__le16 val;
/* __le16 byte_cnt:12; */
@ -1648,6 +1730,25 @@ struct iwl4965_queue_byte_cnt_entry {
/* __le16 rsvd:4; */
} __attribute__ ((packed));
/**
* struct iwl4965_sched_queue_byte_cnt_tbl
*
* Byte Count table
*
* Each Tx queue uses a byte-count table containing 320 entries:
* one 16-bit entry for each of 256 TFDs, plus an additional 64 entries that
* duplicate the first 64 entries (to avoid wrap-around within a Tx window;
* max Tx window is 64 TFDs).
*
* When driver sets up a new TFD, it must also enter the total byte count
* of the frame to be transmitted into the corresponding entry in the byte
* count table for the chosen Tx queue. If the TFD index is 0-63, the driver
* must duplicate the byte count entry in corresponding index 256-319.
*
* "dont_care" padding puts each byte count table on a 1024-byte boundary;
* 4965 assumes tables are separated by 1024 bytes.
*/
struct iwl4965_sched_queue_byte_cnt_tbl {
struct iwl4965_queue_byte_cnt_entry tfd_offset[IWL4965_QUEUE_SIZE +
IWL4965_MAX_WIN_SIZE];
@ -1656,8 +1757,30 @@ struct iwl4965_sched_queue_byte_cnt_tbl {
sizeof(__le16)];
} __attribute__ ((packed));
/* Base physical address of iwl4965_shared is provided to KDR_SCD_DRAM_BASE_ADDR
* and &iwl4965_shared.val0 is provided to FH_RSCSR_CHNL0_STTS_WPTR_REG */
/**
* struct iwl4965_shared - handshake area for Tx and Rx
*
* For convenience in allocating memory, this structure combines 2 areas of
* DRAM which must be shared between driver and 4965. These do not need to
* be combined, if better allocation would result from keeping them separate:
*
* 1) The Tx byte count tables occupy 1024 bytes each (16 KBytes total for
* 16 queues). Driver uses SCD_DRAM_BASE_ADDR to tell 4965 where to find
* the first of these tables. 4965 assumes tables are 1024 bytes apart.
*
* 2) The Rx status (val0 and val1) occupies only 8 bytes. Driver uses
* FH_RSCSR_CHNL0_STTS_WPTR_REG to tell 4965 where to find this area.
* Driver reads val0 to determine the latest Receive Buffer Descriptor (RBD)
* that has been filled by the 4965.
*
* Bit fields val0:
* 31-12: Not used
* 11- 0: Index of last filled Rx buffer descriptor (4965 writes, driver reads)
*
* Bit fields val1:
* 31- 0: Not used
*/
struct iwl4965_shared {
struct iwl4965_sched_queue_byte_cnt_tbl
queues_byte_cnt_tbls[IWL_MAX_NUM_QUEUES];