memory: tegra: Add API needed by the EMC driver

The EMC driver needs to know the number of external memory devices and
also needs to update the EMEM configuration based on the new rate of the
memory bus.

To know how to update the EMEM config, looks up the values of the burst
regs in the DT, for a given timing.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

include/soc/tegra/mc.h

@@ -20,6 +20,12 @@ struct tegra_smmu_enable {
 	unsigned int bit;
 };
 
+struct tegra_mc_timing {
+	unsigned long rate;
+
+	u32 *emem_data;
+};
+
 /* latency allowance */
 struct tegra_mc_la {
 	unsigned int reg;
@@ -84,7 +90,7 @@ struct tegra_mc_soc {
 	const struct tegra_mc_client *clients;
 	unsigned int num_clients;
 
-	const unsigned int *emem_regs;
+	const unsigned long *emem_regs;
 	unsigned int num_emem_regs;
 
 	unsigned int num_address_bits;
@@ -102,6 +108,12 @@ struct tegra_mc {
 
 	const struct tegra_mc_soc *soc;
 	unsigned long tick;
+
+	struct tegra_mc_timing *timings;
+	unsigned int num_timings;
 };
 
+void tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long rate);
+unsigned int tegra_mc_get_emem_device_count(struct tegra_mc *mc);
+
 #endif /* __SOC_TEGRA_MC_H__ */