From: Holger Schurig Date: Thu, 5 Jun 2008 11:07:04 +0000 (+0200) Subject: libertas: document register meanings X-Git-Tag: v2.6.27-rc1~969^2~324^2~53 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5314325692239a977a58fc796b4f4fb783643012;p=linux-2.6 libertas: document register meanings Signed-off-by: Holger Schurig Acked-by: Dan Williams Signed-off-by: John W. Linville --- diff --git a/drivers/net/wireless/libertas/if_cs.c b/drivers/net/wireless/libertas/if_cs.c index b5d0cd4c41..6870276259 100644 --- a/drivers/net/wireless/libertas/if_cs.c +++ b/drivers/net/wireless/libertas/if_cs.c @@ -159,7 +159,9 @@ static int if_cs_poll_while_fw_download(struct if_cs_card *card, uint addr, u8 r -/* First the bitmasks for the host/card interrupt/status registers: */ +/* + * First the bitmasks for the host/card interrupt/status registers: + */ #define IF_CS_BIT_TX 0x0001 #define IF_CS_BIT_RX 0x0002 #define IF_CS_BIT_COMMAND 0x0004 @@ -167,35 +169,104 @@ static int if_cs_poll_while_fw_download(struct if_cs_card *card, uint addr, u8 r #define IF_CS_BIT_EVENT 0x0010 #define IF_CS_BIT_MASK 0x001f -/* And now the individual registers and assorted masks */ + + +/* + * It's not really clear to me what the host status register is for. It + * needs to be set almost in union with "host int cause". The following + * bits from above are used: + * + * IF_CS_BIT_TX driver downloaded a data packet + * IF_CS_BIT_RX driver got a data packet + * IF_CS_BIT_COMMAND driver downloaded a command + * IF_CS_BIT_RESP not used (has some meaning with powerdown) + * IF_CS_BIT_EVENT driver read a host event + */ #define IF_CS_HOST_STATUS 0x00000000 +/* + * With the host int cause register can the host (that is, Linux) cause + * an interrupt in the firmware, to tell the firmware about those events: + * + * IF_CS_BIT_TX a data packet has been downloaded + * IF_CS_BIT_RX a received data packet has retrieved + * IF_CS_BIT_COMMAND a firmware block or a command has been downloaded + * IF_CS_BIT_RESP not used (has some meaning with powerdown) + * IF_CS_BIT_EVENT a host event (link lost etc) has been retrieved + */ #define IF_CS_HOST_INT_CAUSE 0x00000002 +/* + * The host int mask register is used to enable/disable interrupt. However, + * I have the suspicion that disabled interrupts are lost. + */ #define IF_CS_HOST_INT_MASK 0x00000004 +/* + * Used to send or receive data packets: + */ #define IF_CS_HOST_WRITE 0x00000016 #define IF_CS_HOST_WRITE_LEN 0x00000014 - -#define IF_CS_HOST_CMD 0x0000001A -#define IF_CS_HOST_CMD_LEN 0x00000018 - #define IF_CS_READ 0x00000010 #define IF_CS_READ_LEN 0x00000024 +/* + * Used to send commands (and to send firmware block) and to + * receive command responses: + */ +#define IF_CS_HOST_CMD 0x0000001A +#define IF_CS_HOST_CMD_LEN 0x00000018 #define IF_CS_CARD_CMD 0x00000012 #define IF_CS_CARD_CMD_LEN 0x00000030 +/* + * The card status registers shows what the card/firmware actually + * accepts: + * + * IF_CS_BIT_TX you may send a data packet + * IF_CS_BIT_RX you may retrieve a data packet + * IF_CS_BIT_COMMAND you may send a command + * IF_CS_BIT_RESP you may retrieve a command response + * IF_CS_BIT_EVENT the card has a event for use (link lost, snr low etc) + * + * When reading this register several times, you will get back the same + * results --- with one exception: the IF_CS_BIT_EVENT clear itself + * automatically. + * + * Not that we don't rely on BIT_RX,_BIT_RESP or BIT_EVENT because + * we handle this via the card int cause register. + */ #define IF_CS_CARD_STATUS 0x00000020 #define IF_CS_CARD_STATUS_MASK 0x7f00 +/* + * The card int cause register is used by the card/firmware to notify us + * about the following events: + * + * IF_CS_BIT_TX a data packet has successfully been sentx + * IF_CS_BIT_RX a data packet has been received and can be retrieved + * IF_CS_BIT_COMMAND not used + * IF_CS_BIT_RESP the firmware has a command response for us + * IF_CS_BIT_EVENT the card has a event for use (link lost, snr low etc) + */ #define IF_CS_CARD_INT_CAUSE 0x00000022 +/* + * This is used to for handshaking with the card's bootloader/helper image + * to synchronize downloading of firmware blocks. + */ #define IF_CS_CARD_SQ_READ_LOW 0x00000028 #define IF_CS_CARD_SQ_HELPER_OK 0x10 +/* + * The scratch register tells us ... + * + * IF_CS_SCRATCH_BOOT_OK the bootloader runs + * IF_CS_SCRATCH_HELPER_OK the helper firmware already runs + */ #define IF_CS_SCRATCH 0x0000003F - +#define IF_CS_SCRATCH_BOOT_OK 0x00 +#define IF_CS_SCRATCH_HELPER_OK 0x5a /********************************************************************/ @@ -465,11 +536,11 @@ static int if_cs_prog_helper(struct if_cs_card *card) /* "If the value is 0x5a, the firmware is already * downloaded successfully" */ - if (scratch == 0x5a) + if (scratch == IF_CS_SCRATCH_HELPER_OK) goto done; /* "If the value is != 00, it is invalid value of register */ - if (scratch != 0x00) { + if (scratch != IF_CS_SCRATCH_BOOT_OK) { ret = -ENODEV; goto done; }