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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 <sshtylyov@ru.mvista.com>
Cc: mcherkashin@ru.mvista.com
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
This commit is contained in:
Sergei Shtylyov 2008-07-08 19:27:22 +02:00 committed by Bartlomiej Zolnierkiewicz
parent a861beb140
commit ffab6cf44e
1 changed files with 18 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
drivers/ide/arm/palm_bk3710.c
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@ -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));