[PATCH] S5PV210 Correct clock register properties
MyungJoo Ham
myungjoo.ham at samsung.com
Thu Jun 17 04:33:16 EDT 2010
From: MyungJoo Ham <myungJoo.ham at samsung.com>
Corrected shift values of I2S and UART clocks (CLK_GATE_IP3).
I2S (CLK_GATE_IP3) and UART (CLK_GATE_IP3) had wrong register shift
values, which in turn, made them turn on and off wrong clocks.
Please note that each clock definition should access different control
register; otherwise, the system may suffer lockups. For example, if we
have two clock definitions "a" and "b" which access the same register
(and the shift value). Then, when we do:
module B
1 clk = clk_get("b");
2 clk->clk_enable(clk);
3 do something with clk.
4 clk->clk_disable(clk);
module A
1 clk = clk_get("a");
2 clk->clk_enable(clk);
3 do something with clk
4 clk->clk_disable(clk);
And if the execution order is
B1->B2->A1->A2->A3->A4->B3 ...
Then, the system may hang at the point B3.
Therefore, there should be no clock definitions with the same contol
register/shift. If we need to create "aliases", then, creating child
clocks sharing the clock should be fine.
However, we did not mitigate this doppelganger clock problem for "struct
clksrc_clk" vs "struct clk"; look at "hsmmc" vs "mmc_bus". In the next
patch, we plan to let "struct clksrc_clk" access "CLK_SRC_MASK0" and
"CLK_SRC_MASK1"; i.e., clock source enable/disable should mask the clock
source itself, not the clock that is supplied by the clock source.
Signed-off-by: MyungJoo Ham <myungjoo.ham at samsung.com>
---
arch/arm/mach-s5pv210/clock.c | 12 ++++++------
1 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/arm/mach-s5pv210/clock.c b/arch/arm/mach-s5pv210/clock.c
index 154bca4..ec5ad8c 100644
--- a/arch/arm/mach-s5pv210/clock.c
+++ b/arch/arm/mach-s5pv210/clock.c
@@ -406,13 +406,13 @@ static struct clk init_clocks_disable[] = {
.id = 0,
.parent = &clk_p,
.enable = s5pv210_clk_ip3_ctrl,
- .ctrlbit = (1<<4),
+ .ctrlbit = (1<<5),
}, {
.name = "i2s_v32",
.id = 1,
.parent = &clk_p,
.enable = s5pv210_clk_ip3_ctrl,
- .ctrlbit = (1<<4),
+ .ctrlbit = (1<<6),
}
};
@@ -429,25 +429,25 @@ static struct clk init_clocks[] = {
.id = 0,
.parent = &clk_pclk_psys.clk,
.enable = s5pv210_clk_ip3_ctrl,
- .ctrlbit = (1<<7),
+ .ctrlbit = (1<<17),
}, {
.name = "uart",
.id = 1,
.parent = &clk_pclk_psys.clk,
.enable = s5pv210_clk_ip3_ctrl,
- .ctrlbit = (1<<8),
+ .ctrlbit = (1<<18),
}, {
.name = "uart",
.id = 2,
.parent = &clk_pclk_psys.clk,
.enable = s5pv210_clk_ip3_ctrl,
- .ctrlbit = (1<<9),
+ .ctrlbit = (1<<19),
}, {
.name = "uart",
.id = 3,
.parent = &clk_pclk_psys.clk,
.enable = s5pv210_clk_ip3_ctrl,
- .ctrlbit = (1<<10),
+ .ctrlbit = (1<<20),
},
};
--
1.6.3.3
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