From ffab6cf44e9058fe75a33aa86386b22e616a8f6f Mon Sep 17 00:00:00 2001 From: Sergei Shtylyov Date: Tue, 8 Jul 2008 19:27:22 +0200 Subject: [PATCH] palm_bk3710: fix IDECLK period calculation The driver uses completely bogus rounding formula for calculating period from the IDECLK frequency which gives one-off period values (e.g. 11 ns with 100 MHz IDECLK) which in turn can lead to overclocked IDE transfer timings. Actually, rounding is just wrong in this case, so use a mere division for a safe result. While at it, also: - give 'ide_palm_clk' variable a more suitable name; - get rid of the useless 'ideclkp' variable; - drop the LISP stype 'p' postfix from the 'clkp' variable's name. :-) Signed-off-by: Sergei Shtylyov Cc: mcherkashin@ru.mvista.com Signed-off-by: Bartlomiej Zolnierkiewicz --- drivers/ide/arm/palm_bk3710.c | 38 +++++++++++++++++------------------ 1 file changed, 18 insertions(+), 20 deletions(-) diff --git a/drivers/ide/arm/palm_bk3710.c b/drivers/ide/arm/palm_bk3710.c index cc24803fad..2f2b4f4cf2 100644 --- a/drivers/ide/arm/palm_bk3710.c +++ b/drivers/ide/arm/palm_bk3710.c @@ -76,7 +76,7 @@ struct palm_bk3710_udmatiming { #include "../ide-timing.h" -static long ide_palm_clk; +static unsigned ideclk_period; /* in nanoseconds */ static const struct palm_bk3710_udmatiming palm_bk3710_udmatimings[6] = { {160, 240}, /* UDMA Mode 0 */ @@ -86,8 +86,6 @@ static const struct palm_bk3710_udmatiming palm_bk3710_udmatimings[6] = { {85, 60}, /* UDMA Mode 4 */ }; -static struct clk *ideclkp; - static void palm_bk3710_setudmamode(void __iomem *base, unsigned int dev, unsigned int mode) { @@ -97,10 +95,10 @@ static void palm_bk3710_setudmamode(void __iomem *base, unsigned int dev, /* DMA Data Setup */ t0 = DIV_ROUND_UP(palm_bk3710_udmatimings[mode].cycletime, - ide_palm_clk) - 1; - tenv = DIV_ROUND_UP(20, ide_palm_clk) - 1; + ideclk_period) - 1; + tenv = DIV_ROUND_UP(20, ideclk_period) - 1; trp = DIV_ROUND_UP(palm_bk3710_udmatimings[mode].rptime, - ide_palm_clk) - 1; + ideclk_period) - 1; /* udmatim Register */ val16 = readw(base + BK3710_UDMATIM) & (dev ? 0xFF0F : 0xFFF0); @@ -141,8 +139,8 @@ static void palm_bk3710_setdmamode(void __iomem *base, unsigned int dev, cycletime = max_t(int, t->cycle, min_cycle); /* DMA Data Setup */ - t0 = DIV_ROUND_UP(cycletime, ide_palm_clk); - td = DIV_ROUND_UP(t->active, ide_palm_clk); + t0 = DIV_ROUND_UP(cycletime, ideclk_period); + td = DIV_ROUND_UP(t->active, ideclk_period); tkw = t0 - td - 1; td -= 1; @@ -168,9 +166,9 @@ static void palm_bk3710_setpiomode(void __iomem *base, ide_drive_t *mate, struct ide_timing *t; /* PIO Data Setup */ - t0 = DIV_ROUND_UP(cycletime, ide_palm_clk); + t0 = DIV_ROUND_UP(cycletime, ideclk_period); t2 = DIV_ROUND_UP(ide_timing_find_mode(XFER_PIO_0 + mode)->active, - ide_palm_clk); + ideclk_period); t2i = t0 - t2 - 1; t2 -= 1; @@ -192,8 +190,8 @@ static void palm_bk3710_setpiomode(void __iomem *base, ide_drive_t *mate, /* TASKFILE Setup */ t = ide_timing_find_mode(XFER_PIO_0 + mode); - t0 = DIV_ROUND_UP(t->cyc8b, ide_palm_clk); - t2 = DIV_ROUND_UP(t->act8b, ide_palm_clk); + t0 = DIV_ROUND_UP(t->cyc8b, ideclk_period); + t2 = DIV_ROUND_UP(t->act8b, ideclk_period); t2i = t0 - t2 - 1; t2 -= 1; @@ -350,22 +348,22 @@ static const struct ide_port_info __devinitdata palm_bk3710_port_info = { static int __devinit palm_bk3710_probe(struct platform_device *pdev) { - struct clk *clkp; + struct clk *clk; struct resource *mem, *irq; ide_hwif_t *hwif; - unsigned long base; + unsigned long base, rate; int i; hw_regs_t hw; u8 idx[4] = { 0xff, 0xff, 0xff, 0xff }; - clkp = clk_get(NULL, "IDECLK"); - if (IS_ERR(clkp)) + clk = clk_get(NULL, "IDECLK"); + if (IS_ERR(clk)) return -ENODEV; - ideclkp = clkp; - clk_enable(ideclkp); - ide_palm_clk = clk_get_rate(ideclkp)/100000; - ide_palm_clk = (10000/ide_palm_clk) + 1; + clk_enable(clk); + rate = clk_get_rate(clk); + ideclk_period = 1000000000UL / rate; + /* Register the IDE interface with Linux ATA Interface */ memset(&hw, 0, sizeof(hw)); -- 2.39.5