From: Ben Cahill Date: Thu, 29 Nov 2007 03:10:06 +0000 (+0800) Subject: iwlwifi: document shared Tx structures X-Git-Tag: v2.6.25-rc1~1162^2~484 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5d5456fe50cb07347dd350fc045dc98677dbc58f;p=linux-2.6 iwlwifi: document shared Tx structures Document shared Tx structures Signed-off-by: Ben Cahill Signed-off-by: Zhu Yi Signed-off-by: John W. Linville --- diff --git a/drivers/net/wireless/iwlwifi/iwl-4965-hw.h b/drivers/net/wireless/iwlwifi/iwl-4965-hw.h index e7c7f71db8..b548b7979b 100644 --- a/drivers/net/wireless/iwlwifi/iwl-4965-hw.h +++ b/drivers/net/wireless/iwlwifi/iwl-4965-hw.h @@ -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];