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Subject[PATCH 3/8] devfreq: rk3399_dmc: Pass ODT and auto power down parameters to TF-A.
Date
Trusted Firmware-A (TF-A) for rk3399 implements a SiP call to get the
on-die termination (ODT) and auto power down parameters from kernel,
this patch adds the functionality to do this. Also, if DDR clock
frequency is lower than the on-die termination (ODT) disable frequency
this driver should disable the DDR ODT.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---

Changes in v1:
- [RFC 3/10] Add an explanation for platform SIP calls.
- [RFC 3/10] Change if statement for a switch.
- [RFC 3/10] Rename ddr_flag to odt_enable to be more clear.

drivers/devfreq/rk3399_dmc.c | 74 ++++++++++++++++++++++++++++-
include/soc/rockchip/rockchip_sip.h | 1 +
2 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/drivers/devfreq/rk3399_dmc.c b/drivers/devfreq/rk3399_dmc.c
index e795ad2b3f6b..c619dc4ac620 100644
--- a/drivers/devfreq/rk3399_dmc.c
+++ b/drivers/devfreq/rk3399_dmc.c
@@ -18,14 +18,17 @@
#include <linux/devfreq.h>
#include <linux/devfreq-event.h>
#include <linux/interrupt.h>
+#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
+#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/rwsem.h>
#include <linux/suspend.h>

+#include <soc/rockchip/rk3399_grf.h>
#include <soc/rockchip/rockchip_sip.h>

struct dram_timing {
@@ -69,8 +72,11 @@ struct rk3399_dmcfreq {
struct mutex lock;
struct dram_timing timing;
struct regulator *vdd_center;
+ struct regmap *regmap_pmu;
unsigned long rate, target_rate;
unsigned long volt, target_volt;
+ unsigned int odt_dis_freq;
+ int odt_pd_arg0, odt_pd_arg1;
};

static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq,
@@ -80,6 +86,8 @@ static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq,
struct dev_pm_opp *opp;
unsigned long old_clk_rate = dmcfreq->rate;
unsigned long target_volt, target_rate;
+ struct arm_smccc_res res;
+ bool odt_enable = false;
int err;

opp = devfreq_recommended_opp(dev, freq, flags);
@@ -95,6 +103,19 @@ static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq,

mutex_lock(&dmcfreq->lock);

+ if (target_rate >= dmcfreq->odt_dis_freq)
+ odt_enable = true;
+
+ /*
+ * This makes a SMC call to the TF-A to set the DDR PD (power-down)
+ * timings and to enable or disable the ODT (on-die termination)
+ * resistors.
+ */
+ arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, dmcfreq->odt_pd_arg0,
+ dmcfreq->odt_pd_arg1,
+ ROCKCHIP_SIP_CONFIG_DRAM_SET_ODT_PD,
+ odt_enable, 0, 0, 0, &res);
+
/*
* If frequency scaling from low to high, adjust voltage first.
* If frequency scaling from high to low, adjust frequency first.
@@ -294,11 +315,13 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
{
struct arm_smccc_res res;
struct device *dev = &pdev->dev;
- struct device_node *np = pdev->dev.of_node;
+ struct device_node *np = pdev->dev.of_node, *node;
struct rk3399_dmcfreq *data;
int ret, index, size;
uint32_t *timing;
struct dev_pm_opp *opp;
+ u32 ddr_type;
+ u32 val;

data = devm_kzalloc(dev, sizeof(struct rk3399_dmcfreq), GFP_KERNEL);
if (!data)
@@ -334,6 +357,34 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
return ret;
}

+ /* Try to find the optional reference to the pmu syscon */
+ node = of_parse_phandle(np, "rockchip,pmu", 0);
+ if (node) {
+ data->regmap_pmu = syscon_node_to_regmap(node);
+ if (IS_ERR(data->regmap_pmu))
+ return PTR_ERR(data->regmap_pmu);
+ }
+
+ /* Get DDR type */
+ regmap_read(data->regmap_pmu, RK3399_PMUGRF_OS_REG2, &val);
+ ddr_type = (val >> RK3399_PMUGRF_DDRTYPE_SHIFT) &
+ RK3399_PMUGRF_DDRTYPE_MASK;
+
+ /* Get the odt_dis_freq parameter in function of the DDR type */
+ switch (ddr_type) {
+ case RK3399_PMUGRF_DDRTYPE_DDR3:
+ data->odt_dis_freq = data->timing.ddr3_odt_dis_freq;
+ break;
+ case RK3399_PMUGRF_DDRTYPE_LPDDR3:
+ data->odt_dis_freq = data->timing.lpddr3_odt_dis_freq;
+ break;
+ case RK3399_PMUGRF_DDRTYPE_LPDDR4:
+ data->odt_dis_freq = data->timing.lpddr4_odt_dis_freq;
+ break;
+ default:
+ return -EINVAL;
+ };
+
/*
* Get dram timing and pass it to arm trust firmware,
* the dram drvier in arm trust firmware will get these
@@ -358,6 +409,27 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
ROCKCHIP_SIP_CONFIG_DRAM_INIT,
0, 0, 0, 0, &res);

+ /*
+ * In TF-A there is a platform SIP call to set the PD (power-down)
+ * timings and to enable or disable the ODT (on-die termination).
+ * This call needs three arguments as follows:
+ *
+ * arg0:
+ * bit[0-7] : sr_idle
+ * bit[8-15] : sr_mc_gate_idle
+ * bit[16-31] : standby idle
+ * arg1:
+ * bit[0-11] : pd_idle
+ * bit[16-27] : srpd_lite_idle
+ * arg2:
+ * bit[0] : odt enable
+ */
+ data->odt_pd_arg0 = (data->timing.sr_idle & 0xff) |
+ ((data->timing.sr_mc_gate_idle & 0xff) << 8) |
+ ((data->timing.standby_idle & 0xffff) << 16);
+ data->odt_pd_arg1 = (data->timing.pd_idle & 0xfff) |
+ ((data->timing.srpd_lite_idle & 0xfff) << 16);
+
/*
* We add a devfreq driver to our parent since it has a device tree node
* with operating points.
diff --git a/include/soc/rockchip/rockchip_sip.h b/include/soc/rockchip/rockchip_sip.h
index 7e28092c4d3d..ad9482c56797 100644
--- a/include/soc/rockchip/rockchip_sip.h
+++ b/include/soc/rockchip/rockchip_sip.h
@@ -23,5 +23,6 @@
#define ROCKCHIP_SIP_CONFIG_DRAM_GET_RATE 0x05
#define ROCKCHIP_SIP_CONFIG_DRAM_CLR_IRQ 0x06
#define ROCKCHIP_SIP_CONFIG_DRAM_SET_PARAM 0x07
+#define ROCKCHIP_SIP_CONFIG_DRAM_SET_ODT_PD 0x08

#endif
--
2.18.0
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