clk: clk-divider: Fix infinite loop for table divider

From: Fabio Estevam <[email protected]>

Since commit e7489693b3 (clk: divider: Optimize clk_divider_bestdiv loop) we notice a system hang on mx6qboard.

The cause for the hang is well explained by Sascha Hauer [1]:

"This cannot work. _round_up_table is implemented like this:

static int _round_up_table(const struct clk_div_table *table, int div)

{
         const struct clk_div_table *clkt;
         int up = _get_table_maxdiv(table);

         for (clkt = table; clkt->div; clkt++) {
                 if (clkt->div == div)
                         return clkt->div;
                 ...
         }
         ...
}

Here when a table entry matches the input div this function will return exactly the input div. This means _next_div() will always return the same value and clk_divider_bestdiv() has an infinite loop:

         for (i = 1; i <= maxdiv; i = _next_div(divider, i)) {
                 ...
         }

"
[1] http://marc.info/?l=linux-arm-kernel&m=139940658726253&w=2

Remove the 'return _round_up_table' so that the system can work normally again.

Signed-off-by Fabio Estevam <[email protected]>

---
  drivers/clk/clk-divider.c | 2 --
  1 file changed, 2 deletions(-)

drivers/clk/clk-divider.c +0 -0

index b3c8396..fc3e344 100644

drivers/clk/clk-divider.c +0 -0

  	return div;
  }
 

Couldn't we initialize "up" variable to INT_MAX in _round_up_table() as I just proposed in mail thread reporting the regression?