Commit ffab6cf4 authored by Sergei Shtylyov's avatar Sergei Shtylyov Committed by Bartlomiej Zolnierkiewicz
Browse files

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: default avatarSergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: mcherkashin@ru.mvista.com
Signed-off-by: default avatarBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
parent a861beb1

drivers/ide/arm/palm_bk3710.c

+18 −20
Original line number Diff line number Diff line
@@ -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));

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