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| author | Philipp Zabel <philipp.zabel@gmail.com> | 2008-06-29 16:53:34 +0200 |
|---|---|---|
| committer | Eric Miao <eric.miao@marvell.com> | 2008-12-02 07:43:47 +0100 |
| commit | a10c287d393bdd32127d59f3ec8fd7bb80e2fa05 (patch) | |
| tree | 00b75d4d4839eb4eaa56cc301e84dd207420ed54 /arch/arm/mach-pxa/cpufreq-pxa2xx.c | |
| parent | [ARM] pxa: cpufreq-pxa2xx: allow frequency table selection (diff) | |
| download | linux-a10c287d393bdd32127d59f3ec8fd7bb80e2fa05.tar.xz linux-a10c287d393bdd32127d59f3ec8fd7bb80e2fa05.zip | |
[ARM] pxa: cpufreq-pxa2xx: sdram_rows detection support
This patch implements Eric Miao's idea to detect the correct value of
sdram_rows by inspecting the MDCNFG register settings.
It is only tested on two pxa27x devices with 64MB RAM (magician and
hx4700) so far.
Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
Diffstat (limited to 'arch/arm/mach-pxa/cpufreq-pxa2xx.c')
| -rw-r--r-- | arch/arm/mach-pxa/cpufreq-pxa2xx.c | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/arch/arm/mach-pxa/cpufreq-pxa2xx.c b/arch/arm/mach-pxa/cpufreq-pxa2xx.c index 6bb678db537c..771dd4eac935 100644 --- a/arch/arm/mach-pxa/cpufreq-pxa2xx.c +++ b/arch/arm/mach-pxa/cpufreq-pxa2xx.c @@ -64,7 +64,7 @@ typedef struct { /* Define the refresh period in mSec for the SDRAM and the number of rows */ #define SDRAM_TREF 64 /* standard 64ms SDRAM */ -#define SDRAM_ROWS 4096 /* 64MB=8192 32MB=4096 */ +static unsigned int sdram_rows; #define CCLKCFG_TURBO 0x1 #define CCLKCFG_FCS 0x2 @@ -73,6 +73,9 @@ typedef struct { #define MDREFR_DB2_MASK (MDREFR_K2DB2 | MDREFR_K1DB2) #define MDREFR_DRI_MASK 0xFFF +#define MDCNFG_DRAC2(mdcnfg) (((mdcnfg) >> 21) & 0x3) +#define MDCNFG_DRAC0(mdcnfg) (((mdcnfg) >> 5) & 0x3) + /* * PXA255 definitions */ @@ -192,14 +195,28 @@ static void pxa27x_guess_max_freq(void) } } +static void init_sdram_rows(void) +{ + uint32_t mdcnfg = MDCNFG; + unsigned int drac2 = 0, drac0 = 0; + + if (mdcnfg & (MDCNFG_DE2 | MDCNFG_DE3)) + drac2 = MDCNFG_DRAC2(mdcnfg); + + if (mdcnfg & (MDCNFG_DE0 | MDCNFG_DE1)) + drac0 = MDCNFG_DRAC0(mdcnfg); + + sdram_rows = 1 << (11 + max(drac0, drac2)); +} + static u32 mdrefr_dri(unsigned int freq) { u32 dri = 0; if (cpu_is_pxa25x()) - dri = ((freq * SDRAM_TREF) / (SDRAM_ROWS * 32)); + dri = ((freq * SDRAM_TREF) / (sdram_rows * 32)); if (cpu_is_pxa27x()) - dri = ((freq * SDRAM_TREF) / (SDRAM_ROWS - 31)) / 32; + dri = ((freq * SDRAM_TREF) / (sdram_rows - 31)) / 32; return dri; } @@ -334,6 +351,8 @@ static __init int pxa_cpufreq_init(struct cpufreq_policy *policy) if (cpu_is_pxa27x()) pxa27x_guess_max_freq(); + init_sdram_rows(); + /* set default policy and cpuinfo */ policy->cpuinfo.transition_latency = 1000; /* FIXME: 1 ms, assumed */ policy->cur = get_clk_frequency_khz(0); /* current freq */ |