From: Sergei Shtylyov Date: Wed, 13 Dec 2006 08:35:52 +0000 (-0800) Subject: [PATCH] ide: HPT3xx: fix PCI clock detection X-Git-Tag: v2.6.20-rc1~39 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=26c068daf089aa21844236c97d05049b9497cc0a;p=linux-2.6 [PATCH] ide: HPT3xx: fix PCI clock detection Use the f_CNT value saved by the HighPoint BIOS if available as reading it directly would give us a wrong PCI frequency after DPLL has already been calibrated by BIOS. Signed-off-by: Sergei Shtylyov Cc: Bartlomiej Zolnierkiewicz Cc: Alan Cox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/ide/pci/hpt366.c b/drivers/ide/pci/hpt366.c index 4968b16fa3..9fd50801d3 100644 --- a/drivers/ide/pci/hpt366.c +++ b/drivers/ide/pci/hpt366.c @@ -70,6 +70,8 @@ * - fix/remove bad/unused timing tables and use one set of tables for the whole * HPT37x chip family; save space by introducing the separate transfer mode * table in which the mode lookup is done + * - use f_CNT value saved by the HighPoint BIOS as reading it directly gives + * the wrong PCI frequency since DPLL has already been calibrated by BIOS * - fix the hotswap code: it caused RESET- to glitch when tristating the bus, * and for HPT36x the obsolete HDIO_TRISTATE_HWIF handler was called instead * - pass to init_chipset() handlers a copy of the IDE PCI device structure as @@ -1010,8 +1012,8 @@ static void __devinit hpt37x_clocking(ide_hwif_t *hwif) struct hpt_info *info = ide_get_hwifdata(hwif); struct pci_dev *dev = hwif->pci_dev; int adjust, i; - u16 freq; - u32 pll; + u16 freq = 0; + u32 pll, temp = 0; u8 reg5bh = 0, mcr1 = 0; /* @@ -1025,15 +1027,34 @@ static void __devinit hpt37x_clocking(ide_hwif_t *hwif) pci_write_config_byte(dev, 0x5b, 0x23); /* - * set up the PLL. we need to adjust it so that it's stable. - * freq = Tpll * 192 / Tpci + * We'll have to read f_CNT value in order to determine + * the PCI clock frequency according to the following ratio: * - * Todo. For non x86 should probably check the dword is - * set to 0xABCDExxx indicating the BIOS saved f_CNT + * f_CNT = Fpci * 192 / Fdpll + * + * First try reading the register in which the HighPoint BIOS + * saves f_CNT value before reprogramming the DPLL from its + * default setting (which differs for the various chips). + * In case the signature check fails, we'll have to resort to + * reading the f_CNT register itself in hopes that nobody has + * touched the DPLL yet... */ - pci_read_config_word(dev, 0x78, &freq); - freq &= 0x1FF; - + pci_read_config_dword(dev, 0x70, &temp); + if ((temp & 0xFFFFF000) != 0xABCDE000) { + int i; + + printk(KERN_WARNING "HPT37X: no clock data saved by BIOS\n"); + + /* Calculate the average value of f_CNT */ + for (temp = i = 0; i < 128; i++) { + pci_read_config_word(dev, 0x78, &freq); + temp += freq & 0x1ff; + mdelay(1); + } + freq = temp / 128; + } else + freq = temp & 0x1ff; + /* * HPT3xxN chips use different PCI clock information. * Currently we always set up the PLL for them. @@ -1095,11 +1116,8 @@ static void __devinit hpt37x_clocking(ide_hwif_t *hwif) info->flags |= PLL_MODE; /* - * FIXME: make this work correctly, esp with 372N as per - * reference driver code. - * - * adjust PLL based upon PCI clock, enable it, and wait for - * stabilization. + * Adjust the PLL based upon the PCI clock, enable it, and + * wait for stabilization... */ adjust = 0; freq = (pll < F_LOW_PCI_50) ? 2 : 4;