From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 2/6] libata: add xfer_mask handling functions Date: Mon, 6 Mar 2006 04:31:56 +0900 Message-ID: <11415871161635-git-send-email-htejun@gmail.com> References: <11415871161709-git-send-email-htejun@gmail.com> Reply-To: Tejun Heo Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Return-path: Received: from zproxy.gmail.com ([64.233.162.197]:57429 "EHLO zproxy.gmail.com") by vger.kernel.org with ESMTP id S1751805AbWCETcC (ORCPT ); Sun, 5 Mar 2006 14:32:02 -0500 Received: by zproxy.gmail.com with SMTP id 14so1085678nzn for ; Sun, 05 Mar 2006 11:32:01 -0800 (PST) In-Reply-To: <11415871161709-git-send-email-htejun@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: jgarzik@pobox.com, albertcc@tw.ibm.com, alan@lxorguk.ukuu.org.uk, linux-ide@vger.kernel.org Cc: Tejun Heo Add ata_pack_xfermask(), ata_xfer_mask2mode(), ata_xfer_mode2mask(), ata_xfer_mode2shift() and ata_id_xfermask(). These functions will be used by following patches to simplify xfer_mask handling. Signed-off-by: Tejun Heo --- drivers/scsi/libata-core.c | 147 ++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 147 insertions(+), 0 deletions(-) 3247748741bb32ca18e3fa3c0dd14690dbd184a6 diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c index 18418c8..9946618 100644 --- a/drivers/scsi/libata-core.c +++ b/drivers/scsi/libata-core.c @@ -231,6 +231,108 @@ int ata_rwcmd_protocol(struct ata_queued return -1; } +/** + * ata_pack_xfermask - Pack pio, mwdma and udma masks into xfer_mask + * @pio_mask: pio_mask + * @mwdma_mask: mwdma_mask + * @udma_mask: udma_mask + * + * Pack @pio_mask, @mwdma_mask and @udma_mask into a single + * unsigned int xfer_mask. + * + * LOCKING: + * None. + * + * RETURNS: + * Packed xfer_mask. + */ +static unsigned int ata_pack_xfermask(unsigned int pio_mask, + unsigned int mwdma_mask, + unsigned int udma_mask) +{ + return ((pio_mask << ATA_SHIFT_PIO) & ATA_MASK_PIO) | + ((mwdma_mask << ATA_SHIFT_MWDMA) & ATA_MASK_MWDMA) | + ((udma_mask << ATA_SHIFT_UDMA) & ATA_MASK_UDMA); +} + +static const struct ata_xfer_ent { + unsigned int shift, bits; + u8 base; +} ata_xfer_tbl[] = { + { ATA_SHIFT_PIO, ATA_BITS_PIO, XFER_PIO_0 }, + { ATA_SHIFT_MWDMA, ATA_BITS_MWDMA, XFER_MW_DMA_0 }, + { ATA_SHIFT_UDMA, ATA_BITS_UDMA, XFER_UDMA_0 }, + { -1, }, +}; + +/** + * ata_xfer_mask2mode - Find matching XFER_* for the given xfer_mask + * @xfer_mask: xfer_mask of interest + * + * Return matching XFER_* value for @xfer_mask. Only the highest + * bit of @xfer_mask is considered. + * + * LOCKING: + * None. + * + * RETURNS: + * Matching XFER_* value, 0 if no match found. + */ +static u8 ata_xfer_mask2mode(unsigned int xfer_mask) +{ + int highbit = fls(xfer_mask) - 1; + const struct ata_xfer_ent *ent; + + for (ent = ata_xfer_tbl; ent->shift >= 0; ent++) + if (highbit >= ent->shift && highbit < ent->shift + ent->bits) + return ent->base + highbit - ent->shift; + return 0; +} + +/** + * ata_xfer_mode2mask - Find matching xfer_mask for XFER_* + * @xfer_mode: XFER_* of interest + * + * Return matching xfer_mask for @xfer_mode. + * + * LOCKING: + * None. + * + * RETURNS: + * Matching xfer_mask, 0 if no match found. + */ +static unsigned int ata_xfer_mode2mask(u8 xfer_mode) +{ + const struct ata_xfer_ent *ent; + + for (ent = ata_xfer_tbl; ent->shift >= 0; ent++) + if (xfer_mode >= ent->base && xfer_mode < ent->base + ent->bits) + return 1 << (ent->shift + xfer_mode - ent->base); + return 0; +} + +/** + * ata_xfer_mode2shift - Find matching xfer_shift for XFER_* + * @xfer_mode: XFER_* of interest + * + * Return matching xfer_shift for @xfer_mode. + * + * LOCKING: + * None. + * + * RETURNS: + * Matching xfer_shift, -1 if no match found. + */ +static int ata_xfer_mode2shift(unsigned int xfer_mode) +{ + const struct ata_xfer_ent *ent; + + for (ent = ata_xfer_tbl; ent->shift >= 0; ent++) + if (xfer_mode >= ent->base && xfer_mode < ent->base + ent->bits) + return ent->shift; + return -1; +} + static const char * const xfer_mode_str[] = { "PIO0", "PIO1", @@ -682,6 +784,51 @@ static inline void ata_dump_id(const u16 id[93]); } +/** + * ata_id_xfermask - Compute xfermask from the given IDENTIFY data + * @id: IDENTIFY data to compute xfer mask from + * + * Compute the xfermask for this device. This is not as trivial + * as it seems if we must consider early devices correctly. + * + * FIXME: pre IDE drive timing (do we care ?). + * + * LOCKING: + * None. + * + * RETURNS: + * Computed xfermask + */ +static unsigned int ata_id_xfermask(const u16 *id) +{ + unsigned int pio_mask, mwdma_mask, udma_mask; + + /* Usual case. Word 53 indicates word 64 is valid */ + if (id[ATA_ID_FIELD_VALID] & (1 << 1)) { + pio_mask = id[ATA_ID_PIO_MODES] & 0x03; + pio_mask <<= 3; + pio_mask |= 0x7; + } else { + /* If word 64 isn't valid then Word 51 high byte holds + * the PIO timing number for the maximum. Turn it into + * a mask. + */ + pio_mask = (2 << (id[ATA_ID_OLD_PIO_MODES] & 0xFF)) - 1 ; + + /* But wait.. there's more. Design your standards by + * committee and you too can get a free iordy field to + * process. However its the speeds not the modes that + * are supported... Note drivers using the timing API + * will get this right anyway + */ + } + + mwdma_mask = id[ATA_ID_MWDMA_MODES] & 0x07; + udma_mask = id[ATA_ID_UDMA_MODES] & 0xff; + + return ata_pack_xfermask(pio_mask, mwdma_mask, udma_mask); +} + /* * Compute the PIO modes available for this device. This is not as * trivial as it seems if we must consider early devices correctly. -- 1.2.4