diff options
| author | James Wylder <james.wylder@motorola.com> | 2011-06-21 12:51:37 -0500 |
|---|---|---|
| committer | Dan Willemsen <dwillemsen@nvidia.com> | 2011-11-30 21:37:11 -0800 |
| commit | 1dd8408b6a558eef02cb1c11981e1bb12efeecaa (patch) | |
| tree | ba2641b5398f59c7de3cedc43ec923dd6abe2e18 /arch | |
| parent | 3c21ede5c77eb776e7bd528274ab79e30c4bf274 (diff) | |
ARM: tegra: small optimizations for table lookups
Optimization that primarily addresses when cpu frequency
is low but a high memory bandwidth is needed.
Change-Id: I4f800c2368191c744aefd9f83eb96e4c108dbcc3
Signed-off-by: James Wylder <james.wylder@motorola.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/mach-tegra/tegra2_emc.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/arch/arm/mach-tegra/tegra2_emc.c b/arch/arm/mach-tegra/tegra2_emc.c index 3fd81e0e3e01..f1ac82ad5c15 100644 --- a/arch/arm/mach-tegra/tegra2_emc.c +++ b/arch/arm/mach-tegra/tegra2_emc.c @@ -41,6 +41,9 @@ static void __iomem *emc = IO_ADDRESS(TEGRA_EMC_BASE); static const struct tegra_emc_table *tegra_emc_table; static int tegra_emc_table_size; +static unsigned long tegra_emc_max_bus_rate; /* 2 * 1000 * maximum emc_clock rate */ +static unsigned long tegra_emc_min_bus_rate; /* 2 * 1000 * minimum emc_clock rate */ + static inline void emc_writel(u32 val, unsigned long addr) { writel(val, emc + addr); @@ -142,6 +145,14 @@ long tegra_emc_round_rate(unsigned long rate) if (!emc_enable) return -EINVAL; + if (rate >= tegra_emc_max_bus_rate) { + best = tegra_emc_table_size - 1; + goto round_out; + } else if (rate <= tegra_emc_min_bus_rate) { + best = 0; + goto round_out; + } + pr_debug("%s: %lu\n", __func__, rate); /* @@ -160,7 +171,7 @@ long tegra_emc_round_rate(unsigned long rate) if (best < 0) return -EINVAL; - +round_out: pr_debug("%s: using %lu\n", __func__, tegra_emc_table[best].rate); return tegra_emc_table[best].rate * 2 * 1000; @@ -188,11 +199,11 @@ int tegra_emc_set_rate(unsigned long rate) */ rate = rate / 2 / 1000; - for (i = 0; i < tegra_emc_table_size; i++) + for (i = tegra_emc_table_size - 1; i >= 0; i--) if (tegra_emc_table[i].rate == rate) break; - if (i >= tegra_emc_table_size) + if (i < 0) return -EINVAL; pr_debug("%s: setting to %lu\n", __func__, rate); @@ -246,6 +257,10 @@ void tegra_init_emc(const struct tegra_emc_chip *chips, int chips_size) chips[chip_matched].description); tegra_emc_table = chips[chip_matched].table; tegra_emc_table_size = chips[chip_matched].table_size; + + tegra_emc_min_bus_rate = tegra_emc_table[0].rate * 2 * 1000; + tegra_emc_max_bus_rate = tegra_emc_table[tegra_emc_table_size - 1].rate * 2 * 1000; + } else { pr_err("%s: Memory not recognized, memory scaling disabled\n", __func__); |