diff options
| -rw-r--r-- | drivers/memory/tegra/tegra124-emc.c | 185 |
1 files changed, 143 insertions, 42 deletions
diff --git a/drivers/memory/tegra/tegra124-emc.c b/drivers/memory/tegra/tegra124-emc.c index 464f0ceaee63..21f05240682b 100644 --- a/drivers/memory/tegra/tegra124-emc.c +++ b/drivers/memory/tegra/tegra124-emc.c @@ -467,12 +467,20 @@ struct tegra_emc { void __iomem *regs; + struct clk *clk; + enum emc_dram_type dram_type; unsigned int dram_num; struct emc_timing last_timing; struct emc_timing *timings; unsigned int num_timings; + + struct { + struct dentry *root; + unsigned long min_rate; + unsigned long max_rate; + } debugfs; }; /* Timing change sequence functions */ @@ -998,38 +1006,51 @@ tegra_emc_find_node_by_ram_code(struct device_node *node, u32 ram_code) return NULL; } -/* Debugfs entry */ +/* + * debugfs interface + * + * The memory controller driver exposes some files in debugfs that can be used + * to control the EMC frequency. The top-level directory can be found here: + * + * /sys/kernel/debug/emc + * + * It contains the following files: + * + * - available_rates: This file contains a list of valid, space-separated + * EMC frequencies. + * + * - min_rate: Writing a value to this file sets the given frequency as the + * floor of the permitted range. If this is higher than the currently + * configured EMC frequency, this will cause the frequency to be + * increased so that it stays within the valid range. + * + * - max_rate: Similarily to the min_rate file, writing a value to this file + * sets the given frequency as the ceiling of the permitted range. If + * the value is lower than the currently configured EMC frequency, this + * will cause the frequency to be decreased so that it stays within the + * valid range. + */ -static int emc_debug_rate_get(void *data, u64 *rate) +static bool tegra_emc_validate_rate(struct tegra_emc *emc, unsigned long rate) { - struct clk *c = data; - - *rate = clk_get_rate(c); - - return 0; -} + unsigned int i; -static int emc_debug_rate_set(void *data, u64 rate) -{ - struct clk *c = data; + for (i = 0; i < emc->num_timings; i++) + if (rate == emc->timings[i].rate) + return true; - return clk_set_rate(c, rate); + return false; } -DEFINE_SIMPLE_ATTRIBUTE(emc_debug_rate_fops, emc_debug_rate_get, - emc_debug_rate_set, "%lld\n"); - -static int emc_debug_supported_rates_show(struct seq_file *s, void *data) +static int tegra_emc_debug_available_rates_show(struct seq_file *s, + void *data) { struct tegra_emc *emc = s->private; const char *prefix = ""; unsigned int i; for (i = 0; i < emc->num_timings; i++) { - struct emc_timing *timing = &emc->timings[i]; - - seq_printf(s, "%s%lu", prefix, timing->rate); - + seq_printf(s, "%s%lu", prefix, emc->timings[i].rate); prefix = " "; } @@ -1038,46 +1059,126 @@ static int emc_debug_supported_rates_show(struct seq_file *s, void *data) return 0; } -static int emc_debug_supported_rates_open(struct inode *inode, - struct file *file) +static int tegra_emc_debug_available_rates_open(struct inode *inode, + struct file *file) { - return single_open(file, emc_debug_supported_rates_show, + return single_open(file, tegra_emc_debug_available_rates_show, inode->i_private); } -static const struct file_operations emc_debug_supported_rates_fops = { - .open = emc_debug_supported_rates_open, +static const struct file_operations tegra_emc_debug_available_rates_fops = { + .open = tegra_emc_debug_available_rates_open, .read = seq_read, .llseek = seq_lseek, .release = single_release, }; +static int tegra_emc_debug_min_rate_get(void *data, u64 *rate) +{ + struct tegra_emc *emc = data; + + *rate = emc->debugfs.min_rate; + + return 0; +} + +static int tegra_emc_debug_min_rate_set(void *data, u64 rate) +{ + struct tegra_emc *emc = data; + int err; + + if (!tegra_emc_validate_rate(emc, rate)) + return -EINVAL; + + err = clk_set_min_rate(emc->clk, rate); + if (err < 0) + return err; + + emc->debugfs.min_rate = rate; + + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_min_rate_fops, + tegra_emc_debug_min_rate_get, + tegra_emc_debug_min_rate_set, "%llu\n"); + +static int tegra_emc_debug_max_rate_get(void *data, u64 *rate) +{ + struct tegra_emc *emc = data; + + *rate = emc->debugfs.max_rate; + + return 0; +} + +static int tegra_emc_debug_max_rate_set(void *data, u64 rate) +{ + struct tegra_emc *emc = data; + int err; + + if (!tegra_emc_validate_rate(emc, rate)) + return -EINVAL; + + err = clk_set_max_rate(emc->clk, rate); + if (err < 0) + return err; + + emc->debugfs.max_rate = rate; + + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_max_rate_fops, + tegra_emc_debug_max_rate_get, + tegra_emc_debug_max_rate_set, "%llu\n"); + static void emc_debugfs_init(struct device *dev, struct tegra_emc *emc) { - struct dentry *root, *file; - struct clk *clk; + unsigned int i; + int err; - root = debugfs_create_dir("emc", NULL); - if (!root) { - dev_err(dev, "failed to create debugfs directory\n"); - return; + emc->clk = devm_clk_get(dev, "emc"); + if (IS_ERR(emc->clk)) { + if (PTR_ERR(emc->clk) != -ENODEV) { + dev_err(dev, "failed to get EMC clock: %ld\n", + PTR_ERR(emc->clk)); + return; + } } - clk = clk_get_sys("tegra-clk-debug", "emc"); - if (IS_ERR(clk)) { - dev_err(dev, "failed to get debug clock: %ld\n", PTR_ERR(clk)); + emc->debugfs.min_rate = ULONG_MAX; + emc->debugfs.max_rate = 0; + + for (i = 0; i < emc->num_timings; i++) { + if (emc->timings[i].rate < emc->debugfs.min_rate) + emc->debugfs.min_rate = emc->timings[i].rate; + + if (emc->timings[i].rate > emc->debugfs.max_rate) + emc->debugfs.max_rate = emc->timings[i].rate; + } + + err = clk_set_rate_range(emc->clk, emc->debugfs.min_rate, + emc->debugfs.max_rate); + if (err < 0) { + dev_err(dev, "failed to set rate range [%lu-%lu] for %pC\n", + emc->debugfs.min_rate, emc->debugfs.max_rate, + emc->clk); return; } - file = debugfs_create_file("rate", S_IRUGO | S_IWUSR, root, clk, - &emc_debug_rate_fops); - if (!file) - dev_err(dev, "failed to create debugfs entry\n"); + emc->debugfs.root = debugfs_create_dir("emc", NULL); + if (!emc->debugfs.root) { + dev_err(dev, "failed to create debugfs directory\n"); + return; + } - file = debugfs_create_file("supported_rates", S_IRUGO, root, emc, - &emc_debug_supported_rates_fops); - if (!file) - dev_err(dev, "failed to create debugfs entry\n"); + debugfs_create_file("available_rates", S_IRUGO, emc->debugfs.root, emc, + &tegra_emc_debug_available_rates_fops); + debugfs_create_file("min_rate", S_IRUGO | S_IWUSR, emc->debugfs.root, + emc, &tegra_emc_debug_min_rate_fops); + debugfs_create_file("max_rate", S_IRUGO | S_IWUSR, emc->debugfs.root, + emc, &tegra_emc_debug_max_rate_fops); } static int tegra_emc_probe(struct platform_device *pdev) |