Hi Chanwoo,

I'll send a new version soon, just wanted to ask some questions here. See below.

Missatge de Chanwoo Choi [off-list ref] del dia dt., 15 de
maig 2018 a les 0:21:

Hi,

On 2018? 05? 15? 06:16, Enric Balletbo i Serra wrote:

quoted

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.

I have a question.
'disable frequency' is the same meaning of 'disable the DDR ODT'?

Yes, the DT defines an odt_dis_freq parameter, when the DDR frequency
is less than the value in this parameter we disable the ODT on the
DRAM.

quoted

Signed-off-by: Enric Balletbo i Serra <redacted>
---

 drivers/devfreq/rk3399_dmc.c        | 50 ++++++++++++++++++++++++++++-
 include/soc/rockchip/rockchip_sip.h |  1 +
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/drivers/devfreq/rk3399_dmc.c b/drivers/devfreq/rk3399_dmc.c
index d5c03e5abe13..cc1bbca3fb15 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;
+     int dram_flag;
      int err;

      opp = devfreq_recommended_opp(dev, freq, flags);

@@ -95,6 +103,15 @@ static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq,

      mutex_lock(&dmcfreq->lock);

+     dram_flag = 0;

Also, if dram_flag is 0, it mean that disable ODT frequency?

Yes, not a good name, maybe I should just rename it to odt_enable to
be more clear.

If it's right, you better to define the precise variables as following
instead of just integer(0 or 1).
For example,
- ROCKCHIP_SIP_DRAM_FREQ_ENABLE
- ROCKCHIP_SIP_DRAM_FREQ_DISABLE

quoted

+     if (target_rate >= dmcfreq->odt_dis_freq)
+             dram_flag = 1;
+
+     arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, dmcfreq->odt_pd_arg0,
+                   dmcfreq->odt_pd_arg1,
+                   ROCKCHIP_SIP_CONFIG_DRAM_SET_ODT_PD,
+                   dram_flag, 0, 0, 0, &res);
+

This operation is special for only rk3399_dmc. It is difficult
to understand what to do. I recommend you better to add the detailed comment
with code.

Will do.

quoted

      /*
       * If frequency scaling from low to high, adjust voltage first.
       * If frequency scaling from high to low, adjust frequency first.

@@ -294,11 +311,13 @@ 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 +353,29 @@ 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 */
+     if (ddr_type == RK3399_PMUGRF_DDRTYPE_DDR3)
+             data->odt_dis_freq = data->timing.ddr3_odt_dis_freq;
+     else if (ddr_type == RK3399_PMUGRF_DDRTYPE_LPDDR3)
+             data->odt_dis_freq = data->timing.lpddr3_odt_dis_freq;
+     else if (ddr_type == RK3399_PMUGRF_DDRTYPE_LPDDR4)
+             data->odt_dis_freq = data->timing.lpddr4_odt_dis_freq;
+     else
+             return -EINVAL;
+

how about using 'switch' statement?

Ok

quoted

      /*
       * Get dram timing and pass it to arm trust firmware,
       * the dram drvier in arm trust firmware will get these

@@ -358,6 +400,12 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
                    ROCKCHIP_SIP_CONFIG_DRAM_INIT,
                    0, 0, 0, 0, &res);

+     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);
+

odt_pd_arg0 and odt_pd_arg1 might be used for disabling/enabling the ODT frequency.
As I commented, it depend on only rk3399_dmc. You better to add detailed comment.

Ok

And I prefer to define the XXX_SHIFT/XXX_MASK definition instead of
using 8/16/0xff/0xffff for the readability.

I tried to add the XXX_SHIFT/XXX_MASK definitions and IMHO the
readability is worst if I use a maximum line length of 80 characters.
These masks are only used here, let me try to convince you by adding a
good doc in the next version and if you still prefer I add the
definition I'll do.

quoted

      /*
       * 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

--
Best Regards,
Chanwoo Choi
Samsung Electronics

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Cheers,
 Enric