From: Ben Cahill Date: Thu, 29 Nov 2007 03:10:04 +0000 (+0800) Subject: iwlwifi: document Rx registers X-Git-Tag: v2.6.25-rc1~1162^2~486 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4d3cf5f7c2290c6cbe7ae1722bf2f938c81ef887;p=linux-2.6 iwlwifi: document Rx registers Document Rx registers Document Tx circular buffer base registers 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 8698bf77fd..f194d813f4 100644 --- a/drivers/net/wireless/iwlwifi/iwl-4965-hw.h +++ b/drivers/net/wireless/iwlwifi/iwl-4965-hw.h @@ -1286,7 +1286,7 @@ enum { /* Flow Handler Definitions */ /****************************/ -/* +/** * This I/O area is directly read/writable by driver (e.g. Linux uses writel()) * Addresses are offsets from device's PCI hardware base address. */ @@ -1313,35 +1313,193 @@ enum { #define IWL_FH_KW_MEM_ADDR_REG (FH_MEM_LOWER_BOUND + 0x97C) -/* CBBC Area - Circular buffers base address cache pointers table */ +/** + * TFD Circular Buffers Base (CBBC) addresses + * + * 4965 has 16 base pointer registers, one for each of 16 host-DRAM-resident + * circular buffers (CBs/queues) containing Transmit Frame Descriptors (TFDs) + * (see struct iwl_tfd_frame). These 16 pointer registers are offset by 0x04 + * bytes from one another. Each TFD circular buffer in DRAM must be 256-byte + * aligned (address bits 0-7 must be 0). + * + * Bit fields in each pointer register: + * 27-0: TFD CB physical base address [35:8], must be 256-byte aligned + */ #define FH_MEM_CBBC_LOWER_BOUND (FH_MEM_LOWER_BOUND + 0x9D0) #define FH_MEM_CBBC_UPPER_BOUND (FH_MEM_LOWER_BOUND + 0xA10) -/* queues 0 - 15 */ + +/* Find TFD CB base pointer for given queue (range 0-15). */ #define FH_MEM_CBBC_QUEUE(x) (FH_MEM_CBBC_LOWER_BOUND + (x) * 0x4) -/* RSCSR Area */ + +/** + * Rx SRAM Control and Status Registers (RSCSR) + * + * These registers provide handshake between driver and 4965 for the Rx queue + * (this queue handles *all* command responses, notifications, Rx data, etc. + * sent from 4965 uCode to host driver). Unlike Tx, there is only one Rx + * queue, and only one Rx DMA/FIFO channel. Also unlike Tx, which can + * concatenate up to 20 DRAM buffers to form a Tx frame, each Receive Buffer + * Descriptor (RBD) points to only one Rx Buffer (RB); there is a 1:1 + * mapping between RBDs and RBs. + * + * Driver must allocate host DRAM memory for the following, and set the + * physical address of each into 4965 registers: + * + * 1) Receive Buffer Descriptor (RBD) circular buffer (CB), typically with 256 + * entries (although any power of 2, up to 4096, is selectable by driver). + * Each entry (1 dword) points to a receive buffer (RB) of consistent size + * (typically 4K, although 8K or 16K are also selectable by driver). + * Driver sets up RB size and number of RBDs in the CB via Rx config + * register FH_MEM_RCSR_CHNL0_CONFIG_REG. + * + * Bit fields within one RBD: + * 27-0: Receive Buffer physical address bits [35:8], 256-byte aligned + * + * Driver sets physical address [35:8] of base of RBD circular buffer + * into FH_RSCSR_CHNL0_RBDCB_BASE_REG [27:0]. + * + * 2) Rx status buffer, 8 bytes, in which 4965 indicates which Rx Buffers + * (RBs) have been filled, via a "write pointer", actually the index of + * the RB's corresponding RBD within the circular buffer. Driver sets + * physical address [35:4] into FH_RSCSR_CHNL0_STTS_WPTR_REG [31:0]. + * + * Bit fields in lower dword of Rx status buffer (upper dword not used + * by driver; see struct iwl4965_shared, val0): + * 31-12: Not used by driver + * 11- 0: Index of last filled Rx buffer descriptor + * (4965 writes, driver reads this value) + * + * As the driver prepares Receive Buffers (RBs) for 4965 to fill, driver must + * enter pointers to these RBs into contiguous RBD circular buffer entries, + * and update the 4965's "write" index register, FH_RSCSR_CHNL0_RBDCB_WPTR_REG. + * + * This "write" index corresponds to the *next* RBD that the driver will make + * available, i.e. one RBD past the tail of the ready-to-fill RBDs within + * the circular buffer. This value should initially be 0 (before preparing any + * RBs), should be 8 after preparing the first 8 RBs (for example), and must + * wrap back to 0 at the end of the circular buffer (but don't wrap before + * "read" index has advanced past 1! See below). + * NOTE: 4965 EXPECTS THE WRITE INDEX TO BE INCREMENTED IN MULTIPLES OF 8. + * + * As the 4965 fills RBs (referenced from contiguous RBDs within the circular + * buffer), it updates the Rx status buffer in host DRAM, 2) described above, + * to tell the driver the index of the latest filled RBD. The driver must + * read this "read" index from DRAM after receiving an Rx interrupt from 4965. + * + * The driver must also internally keep track of a third index, which is the + * next RBD to process. When receiving an Rx interrupt, driver should process + * all filled but unprocessed RBs up to, but not including, the RB + * corresponding to the "read" index. For example, if "read" index becomes "1", + * driver may process the RB pointed to by RBD 0. Depending on volume of + * traffic, there may be many RBs to process. + * + * If read index == write index, 4965 thinks there is no room to put new data. + * Due to this, the maximum number of filled RBs is 255, instead of 256. To + * be safe, make sure that there is a gap of at least 2 RBDs between "write" + * and "read" indexes; that is, make sure that there are no more than 254 + * buffers waiting to be filled. + */ #define FH_MEM_RSCSR_LOWER_BOUND (FH_MEM_LOWER_BOUND + 0xBC0) #define FH_MEM_RSCSR_UPPER_BOUND (FH_MEM_LOWER_BOUND + 0xC00) #define FH_MEM_RSCSR_CHNL0 (FH_MEM_RSCSR_LOWER_BOUND) +/** + * Physical base address of 8-byte Rx Status buffer. + * Bit fields: + * 31-0: Rx status buffer physical base address [35:4], must 16-byte aligned. + */ #define FH_RSCSR_CHNL0_STTS_WPTR_REG (FH_MEM_RSCSR_CHNL0) + +/** + * Physical base address of Rx Buffer Descriptor Circular Buffer. + * Bit fields: + * 27-0: RBD CD physical base address [35:8], must be 256-byte aligned. + */ #define FH_RSCSR_CHNL0_RBDCB_BASE_REG (FH_MEM_RSCSR_CHNL0 + 0x004) + +/** + * Rx write pointer (index, really!). + * Bit fields: + * 11-0: Index of driver's most recent prepared-to-be-filled RBD, + 1. + * NOTE: For 256-entry circular buffer, use only bits [7:0]. + */ #define FH_RSCSR_CHNL0_RBDCB_WPTR_REG (FH_MEM_RSCSR_CHNL0 + 0x008) -/* RCSR Area - Registers address map */ + +/** + * Rx Config/Status Registers (RCSR) + * Rx Config Reg for channel 0 (only channel used) + * + * Driver must initialize FH_MEM_RCSR_CHNL0_CONFIG_REG as follows for + * normal operation (see bit fields). + * + * Clearing FH_MEM_RCSR_CHNL0_CONFIG_REG to 0 turns off Rx DMA. + * Driver should poll FH_MEM_RSSR_RX_STATUS_REG for + * FH_RSSR_CHNL0_RX_STATUS_CHNL_IDLE (bit 24) before continuing. + * + * Bit fields: + * 31-30: Rx DMA channel enable: '00' off/pause, '01' pause at end of frame, + * '10' operate normally + * 29-24: reserved + * 23-20: # RBDs in circular buffer = 2^value; use "8" for 256 RBDs (normal), + * min "5" for 32 RBDs, max "12" for 4096 RBDs. + * 19-18: reserved + * 17-16: size of each receive buffer; '00' 4K (normal), '01' 8K, + * '10' 12K, '11' 16K. + * 15-14: reserved + * 13-12: IRQ destination; '00' none, '01' host driver (normal operation) + * 11- 4: timeout for closing Rx buffer and interrupting host (units 32 usec) + * typical value 0x10 (about 1/2 msec) + * 3- 0: reserved + */ #define FH_MEM_RCSR_LOWER_BOUND (FH_MEM_LOWER_BOUND + 0xC00) #define FH_MEM_RCSR_UPPER_BOUND (FH_MEM_LOWER_BOUND + 0xCC0) #define FH_MEM_RCSR_CHNL0 (FH_MEM_RCSR_LOWER_BOUND) #define FH_MEM_RCSR_CHNL0_CONFIG_REG (FH_MEM_RCSR_CHNL0) -/* RSSR Area - Rx shared ctrl & status registers */ +#define FH_RCSR_CHNL0_RX_CONFIG_RB_TIMEOUT_MASK (0x00000FF0) /* bit 4-11 */ +#define FH_RCSR_CHNL0_RX_CONFIG_IRQ_DEST_MASK (0x00001000) /* bit 12 */ +#define FH_RCSR_CHNL0_RX_CONFIG_SINGLE_FRAME_MASK (0x00008000) /* bit 15 */ +#define FH_RCSR_CHNL0_RX_CONFIG_RB_SIZE_MASK (0x00030000) /* bits 16-17 */ +#define FH_RCSR_CHNL0_RX_CONFIG_RBDBC_SIZE_MASK (0x00F00000) /* bits 20-23 */ +#define FH_RCSR_CHNL0_RX_CONFIG_DMA_CHNL_EN_MASK (0xC0000000) /* bits 30-31 */ + +#define FH_RCSR_RX_CONFIG_RBDCB_SIZE_BITSHIFT (20) +#define FH_RCSR_RX_CONFIG_RB_SIZE_BITSHIFT (16) + +#define FH_RCSR_RX_CONFIG_CHNL_EN_PAUSE_VAL (0x00000000) +#define FH_RCSR_RX_CONFIG_CHNL_EN_PAUSE_EOF_VAL (0x40000000) +#define FH_RCSR_RX_CONFIG_CHNL_EN_ENABLE_VAL (0x80000000) + +#define IWL_FH_RCSR_RX_CONFIG_REG_VAL_RB_SIZE_4K (0x00000000) + +#define FH_RCSR_CHNL0_RX_CONFIG_IRQ_DEST_NO_INT_VAL (0x00000000) +#define FH_RCSR_CHNL0_RX_CONFIG_IRQ_DEST_INT_HOST_VAL (0x00001000) + + +/** + * Rx Shared Status Registers (RSSR) + * + * After stopping Rx DMA channel (writing 0 to FH_MEM_RCSR_CHNL0_CONFIG_REG), + * driver must poll FH_MEM_RSSR_RX_STATUS_REG until Rx channel is idle. + * + * Bit fields: + * 24: 1 = Channel 0 is idle + * + * FH_MEM_RSSR_SHARED_CTRL_REG and FH_MEM_RSSR_RX_ENABLE_ERR_IRQ2DRV contain + * default values that should not be altered by the driver. + */ #define FH_MEM_RSSR_LOWER_BOUND (FH_MEM_LOWER_BOUND + 0xC40) #define FH_MEM_RSSR_UPPER_BOUND (FH_MEM_LOWER_BOUND + 0xD00) + #define FH_MEM_RSSR_SHARED_CTRL_REG (FH_MEM_RSSR_LOWER_BOUND) #define FH_MEM_RSSR_RX_STATUS_REG (FH_MEM_RSSR_LOWER_BOUND + 0x004) #define FH_MEM_RSSR_RX_ENABLE_ERR_IRQ2DRV (FH_MEM_RSSR_LOWER_BOUND + 0x008) +#define FH_RSSR_CHNL0_RX_STATUS_CHNL_IDLE (0x01000000) + /* TCSR */ #define IWL_FH_TCSR_LOWER_BOUND (FH_MEM_LOWER_BOUND + 0xD00) #define IWL_FH_TCSR_UPPER_BOUND (FH_MEM_LOWER_BOUND + 0xE60) @@ -1369,17 +1527,6 @@ enum { #define IWL_FH_TCSR_TX_CONFIG_REG_VAL_DMA_CHNL_ENABLE (0x80000000) -/* RCSR: channel 0 rx_config register defines */ - -#define FH_RCSR_RX_CONFIG_RBDCB_SIZE_BITSHIFT (20) - -#define FH_RCSR_RX_CONFIG_CHNL_EN_ENABLE_VAL (0x80000000) - -#define IWL_FH_RCSR_RX_CONFIG_REG_VAL_RB_SIZE_4K (0x00000000) - -/* RCSR channel 0 config register values */ -#define FH_RCSR_CHNL0_RX_CONFIG_IRQ_DEST_INT_HOST_VAL (0x00001000) - #define SCD_WIN_SIZE 64 #define SCD_FRAME_LIMIT 64