diff options
Diffstat (limited to 'drivers/memory/tegra/tegra30.c')
| -rw-r--r-- | drivers/memory/tegra/tegra30.c | 173 |
1 files changed, 172 insertions, 1 deletions
diff --git a/drivers/memory/tegra/tegra30.c b/drivers/memory/tegra/tegra30.c index d0314f29608d..ea849003014b 100644 --- a/drivers/memory/tegra/tegra30.c +++ b/drivers/memory/tegra/tegra30.c @@ -4,7 +4,8 @@ */ #include <linux/of.h> -#include <linux/mm.h> +#include <linux/of_device.h> +#include <linux/slab.h> #include <dt-bindings/memory/tegra30-mc.h> @@ -1083,6 +1084,175 @@ static const struct tegra_mc_reset tegra30_mc_resets[] = { TEGRA30_MC_RESET(VI, 0x200, 0x204, 17), }; +static void tegra30_mc_tune_client_latency(struct tegra_mc *mc, + const struct tegra_mc_client *client, + unsigned int bandwidth_mbytes_sec) +{ + u32 arb_tolerance_compensation_nsec, arb_tolerance_compensation_div; + const struct tegra_mc_la *la = &client->la; + unsigned int fifo_size = client->fifo_size; + u32 arb_nsec, la_ticks, value; + + /* see 18.4.1 Client Configuration in Tegra3 TRM v03p */ + if (bandwidth_mbytes_sec) + arb_nsec = fifo_size * NSEC_PER_USEC / bandwidth_mbytes_sec; + else + arb_nsec = U32_MAX; + + /* + * Latency allowness should be set with consideration for the module's + * latency tolerance and internal buffering capabilities. + * + * Display memory clients use isochronous transfers and have very low + * tolerance to a belated transfers. Hence we need to compensate the + * memory arbitration imperfection for them in order to prevent FIFO + * underflow condition when memory bus is busy. + * + * VI clients also need a stronger compensation. + */ + switch (client->swgroup) { + case TEGRA_SWGROUP_MPCORE: + case TEGRA_SWGROUP_PTC: + /* + * We always want lower latency for these clients, hence + * don't touch them. + */ + return; + + case TEGRA_SWGROUP_DC: + case TEGRA_SWGROUP_DCB: + arb_tolerance_compensation_nsec = 1050; + arb_tolerance_compensation_div = 2; + break; + + case TEGRA_SWGROUP_VI: + arb_tolerance_compensation_nsec = 1050; + arb_tolerance_compensation_div = 1; + break; + + default: + arb_tolerance_compensation_nsec = 150; + arb_tolerance_compensation_div = 1; + break; + } + + if (arb_nsec > arb_tolerance_compensation_nsec) + arb_nsec -= arb_tolerance_compensation_nsec; + else + arb_nsec = 0; + + arb_nsec /= arb_tolerance_compensation_div; + + /* + * Latency allowance is a number of ticks a request from a particular + * client may wait in the EMEM arbiter before it becomes a high-priority + * request. + */ + la_ticks = arb_nsec / mc->tick; + la_ticks = min(la_ticks, la->mask); + + value = mc_readl(mc, la->reg); + value &= ~(la->mask << la->shift); + value |= la_ticks << la->shift; + mc_writel(mc, value, la->reg); +} + +static int tegra30_mc_icc_set(struct icc_node *src, struct icc_node *dst) +{ + struct tegra_mc *mc = icc_provider_to_tegra_mc(src->provider); + const struct tegra_mc_client *client = &mc->soc->clients[src->id]; + u64 peak_bandwidth = icc_units_to_bps(src->peak_bw); + + /* + * Skip pre-initialization that is done by icc_node_add(), which sets + * bandwidth to maximum for all clients before drivers are loaded. + * + * This doesn't make sense for us because we don't have drivers for all + * clients and it's okay to keep configuration left from bootloader + * during boot, at least for today. + */ + if (src == dst) + return 0; + + /* convert bytes/sec to megabytes/sec */ + do_div(peak_bandwidth, 1000000); + + tegra30_mc_tune_client_latency(mc, client, peak_bandwidth); + + return 0; +} + +static int tegra30_mc_icc_aggreate(struct icc_node *node, u32 tag, u32 avg_bw, + u32 peak_bw, u32 *agg_avg, u32 *agg_peak) +{ + /* + * ISO clients need to reserve extra bandwidth up-front because + * there could be high bandwidth pressure during initial filling + * of the client's FIFO buffers. Secondly, we need to take into + * account impurities of the memory subsystem. + */ + if (tag & TEGRA_MC_ICC_TAG_ISO) + peak_bw = tegra_mc_scale_percents(peak_bw, 400); + + *agg_avg += avg_bw; + *agg_peak = max(*agg_peak, peak_bw); + + return 0; +} + +static struct icc_node_data * +tegra30_mc_of_icc_xlate_extended(struct of_phandle_args *spec, void *data) +{ + struct tegra_mc *mc = icc_provider_to_tegra_mc(data); + const struct tegra_mc_client *client; + unsigned int i, idx = spec->args[0]; + struct icc_node_data *ndata; + struct icc_node *node; + + list_for_each_entry(node, &mc->provider.nodes, node_list) { + if (node->id != idx) + continue; + + ndata = kzalloc(sizeof(*ndata), GFP_KERNEL); + if (!ndata) + return ERR_PTR(-ENOMEM); + + client = &mc->soc->clients[idx]; + ndata->node = node; + + switch (client->swgroup) { + case TEGRA_SWGROUP_DC: + case TEGRA_SWGROUP_DCB: + case TEGRA_SWGROUP_PTC: + case TEGRA_SWGROUP_VI: + /* these clients are isochronous by default */ + ndata->tag = TEGRA_MC_ICC_TAG_ISO; + break; + + default: + ndata->tag = TEGRA_MC_ICC_TAG_DEFAULT; + break; + } + + return ndata; + } + + for (i = 0; i < mc->soc->num_clients; i++) { + if (mc->soc->clients[i].id == idx) + return ERR_PTR(-EPROBE_DEFER); + } + + dev_err(mc->dev, "invalid ICC client ID %u\n", idx); + + return ERR_PTR(-EINVAL); +} + +static const struct tegra_mc_icc_ops tegra30_mc_icc_ops = { + .xlate_extended = tegra30_mc_of_icc_xlate_extended, + .aggregate = tegra30_mc_icc_aggreate, + .set = tegra30_mc_icc_set, +}; + const struct tegra_mc_soc tegra30_mc_soc = { .clients = tegra30_mc_clients, .num_clients = ARRAY_SIZE(tegra30_mc_clients), @@ -1097,4 +1267,5 @@ const struct tegra_mc_soc tegra30_mc_soc = { .reset_ops = &tegra_mc_reset_ops_common, .resets = tegra30_mc_resets, .num_resets = ARRAY_SIZE(tegra30_mc_resets), + .icc_ops = &tegra30_mc_icc_ops, }; |