[PATCH v12 1/5] memory: tegra124-emc: Make driver modular

From: Dmitry Osipenko
Date: Mon Dec 28 2020 - 10:50:53 EST

Add modularization support to the Tegra124 EMC driver, which now can be
compiled as a loadable kernel module.

Note that EMC clock must be registered at clk-init time, otherwise PLLM
will be disabled as unused clock at boot time if EMC driver is compiled
as a module. Hence add a prepare/complete callbacks. similarly to what is
done for the Tegra20/30 EMC drivers.

Tested-by: Nicolas Chauvet <kwizart@xxxxxxxxx>
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
drivers/clk/tegra/Kconfig | 3 ++
drivers/clk/tegra/Makefile | 2 +-
drivers/clk/tegra/clk-tegra124-emc.c | 41 ++++++++++++++++++++++++----
drivers/clk/tegra/clk-tegra124.c | 26 ++++++++++++++++--
drivers/clk/tegra/clk.h | 18 ++++++++----
drivers/memory/tegra/Kconfig | 3 +-
drivers/memory/tegra/tegra124-emc.c | 31 ++++++++++++++-------
include/linux/clk/tegra.h | 8 ++++++
include/soc/tegra/emc.h | 16 -----------
9 files changed, 106 insertions(+), 42 deletions(-)
delete mode 100644 include/soc/tegra/emc.h

diff --git a/drivers/clk/tegra/Kconfig b/drivers/clk/tegra/Kconfig
index deaa4605824c..90df619dc087 100644
--- a/drivers/clk/tegra/Kconfig
+++ b/drivers/clk/tegra/Kconfig
@@ -7,3 +7,6 @@ config TEGRA_CLK_DFLL
depends on ARCH_TEGRA_124_SOC || ARCH_TEGRA_210_SOC
select PM_OPP
def_bool y
+
+config TEGRA124_CLK_EMC
+ bool
diff --git a/drivers/clk/tegra/Makefile b/drivers/clk/tegra/Makefile
index eec2313fd37e..7b1816856eb5 100644
--- a/drivers/clk/tegra/Makefile
+++ b/drivers/clk/tegra/Makefile
@@ -22,7 +22,7 @@ obj-$(CONFIG_ARCH_TEGRA_3x_SOC) += clk-tegra20-emc.o
obj-$(CONFIG_ARCH_TEGRA_114_SOC) += clk-tegra114.o
obj-$(CONFIG_ARCH_TEGRA_124_SOC) += clk-tegra124.o
obj-$(CONFIG_TEGRA_CLK_DFLL) += clk-tegra124-dfll-fcpu.o
-obj-$(CONFIG_TEGRA124_EMC) += clk-tegra124-emc.o
+obj-$(CONFIG_TEGRA124_CLK_EMC) += clk-tegra124-emc.o
obj-$(CONFIG_ARCH_TEGRA_132_SOC) += clk-tegra124.o
obj-y += cvb.o
obj-$(CONFIG_ARCH_TEGRA_210_SOC) += clk-tegra210.o
diff --git a/drivers/clk/tegra/clk-tegra124-emc.c b/drivers/clk/tegra/clk-tegra124-emc.c
index 745f9faa98d8..bdf6f4a51617 100644
--- a/drivers/clk/tegra/clk-tegra124-emc.c
+++ b/drivers/clk/tegra/clk-tegra124-emc.c
@@ -11,7 +11,9 @@
#include <linux/clk-provider.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
+#include <linux/clk/tegra.h>
#include <linux/delay.h>
+#include <linux/export.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
@@ -21,7 +23,6 @@
#include <linux/string.h>

#include <soc/tegra/fuse.h>
-#include <soc/tegra/emc.h>

#include "clk.h"

@@ -80,6 +81,9 @@ struct tegra_clk_emc {
int num_timings;
struct emc_timing *timings;
spinlock_t *lock;
+
+ tegra124_emc_prepare_timing_change_cb *prepare_timing_change;
+ tegra124_emc_complete_timing_change_cb *complete_timing_change;
};

/* Common clock framework callback implementations */
@@ -176,6 +180,9 @@ static struct tegra_emc *emc_ensure_emc_driver(struct tegra_clk_emc *tegra)
if (tegra->emc)
return tegra->emc;

+ if (!tegra->prepare_timing_change || !tegra->complete_timing_change)
+ return NULL;
+
if (!tegra->emc_node)
return NULL;

@@ -241,7 +248,7 @@ static int emc_set_timing(struct tegra_clk_emc *tegra,

div = timing->parent_rate / (timing->rate / 2) - 2;

- err = tegra_emc_prepare_timing_change(emc, timing->rate);
+ err = tegra->prepare_timing_change(emc, timing->rate);
if (err)
return err;

@@ -259,7 +266,7 @@ static int emc_set_timing(struct tegra_clk_emc *tegra,

spin_unlock_irqrestore(tegra->lock, flags);

- tegra_emc_complete_timing_change(emc, timing->rate);
+ tegra->complete_timing_change(emc, timing->rate);

clk_hw_reparent(&tegra->hw, __clk_get_hw(timing->parent));
clk_disable_unprepare(tegra->prev_parent);
@@ -473,8 +480,8 @@ static const struct clk_ops tegra_clk_emc_ops = {
.get_parent = emc_get_parent,
};

-struct clk *tegra_clk_register_emc(void __iomem *base, struct device_node *np,
- spinlock_t *lock)
+struct clk *tegra124_clk_register_emc(void __iomem *base, struct device_node *np,
+ spinlock_t *lock)
{
struct tegra_clk_emc *tegra;
struct clk_init_data init;
@@ -538,3 +545,27 @@ struct clk *tegra_clk_register_emc(void __iomem *base, struct device_node *np,

return clk;
};
+
+void tegra124_clk_set_emc_callbacks(tegra124_emc_prepare_timing_change_cb *prep_cb,
+ tegra124_emc_complete_timing_change_cb *complete_cb)
+{
+ struct clk *clk = __clk_lookup("emc");
+ struct tegra_clk_emc *tegra;
+ struct clk_hw *hw;
+
+ if (clk) {
+ hw = __clk_get_hw(clk);
+ tegra = container_of(hw, struct tegra_clk_emc, hw);
+
+ tegra->prepare_timing_change = prep_cb;
+ tegra->complete_timing_change = complete_cb;
+ }
+}
+EXPORT_SYMBOL_GPL(tegra124_clk_set_emc_callbacks);
+
+bool tegra124_clk_emc_driver_available(struct clk_hw *hw)
+{
+ struct tegra_clk_emc *tegra = container_of(hw, struct tegra_clk_emc, hw);
+
+ return tegra->prepare_timing_change && tegra->complete_timing_change;
+}
diff --git a/drivers/clk/tegra/clk-tegra124.c b/drivers/clk/tegra/clk-tegra124.c
index e931319dcc9d..934520aab6e3 100644
--- a/drivers/clk/tegra/clk-tegra124.c
+++ b/drivers/clk/tegra/clk-tegra124.c
@@ -1500,6 +1500,26 @@ static void __init tegra124_132_clock_init_pre(struct device_node *np)
writel(plld_base, clk_base + PLLD_BASE);
}

+static struct clk *tegra124_clk_src_onecell_get(struct of_phandle_args *clkspec,
+ void *data)
+{
+ struct clk_hw *hw;
+ struct clk *clk;
+
+ clk = of_clk_src_onecell_get(clkspec, data);
+ if (IS_ERR(clk))
+ return clk;
+
+ hw = __clk_get_hw(clk);
+
+ if (clkspec->args[0] == TEGRA124_CLK_EMC) {
+ if (!tegra124_clk_emc_driver_available(hw))
+ return ERR_PTR(-EPROBE_DEFER);
+ }
+
+ return clk;
+}
+
/**
* tegra124_132_clock_init_post - clock initialization postamble for T124/T132
* @np: struct device_node * of the DT node for the SoC CAR IP block
@@ -1516,10 +1536,10 @@ static void __init tegra124_132_clock_init_post(struct device_node *np)
&pll_x_params);
tegra_init_special_resets(1, tegra124_reset_assert,
tegra124_reset_deassert);
- tegra_add_of_provider(np, of_clk_src_onecell_get);
+ tegra_add_of_provider(np, tegra124_clk_src_onecell_get);

- clks[TEGRA124_CLK_EMC] = tegra_clk_register_emc(clk_base, np,
- &emc_lock);
+ clks[TEGRA124_CLK_EMC] = tegra124_clk_register_emc(clk_base, np,
+ &emc_lock);

tegra_register_devclks(devclks, ARRAY_SIZE(devclks));

diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h
index 6b565f6b5f66..c3e36b5dcc75 100644
--- a/drivers/clk/tegra/clk.h
+++ b/drivers/clk/tegra/clk.h
@@ -881,16 +881,22 @@ void tegra_super_clk_gen5_init(void __iomem *clk_base,
void __iomem *pmc_base, struct tegra_clk *tegra_clks,
struct tegra_clk_pll_params *pll_params);

-#ifdef CONFIG_TEGRA124_EMC
-struct clk *tegra_clk_register_emc(void __iomem *base, struct device_node *np,
- spinlock_t *lock);
+#ifdef CONFIG_TEGRA124_CLK_EMC
+struct clk *tegra124_clk_register_emc(void __iomem *base, struct device_node *np,
+ spinlock_t *lock);
+bool tegra124_clk_emc_driver_available(struct clk_hw *emc_hw);
#else
-static inline struct clk *tegra_clk_register_emc(void __iomem *base,
- struct device_node *np,
- spinlock_t *lock)
+static inline struct clk *
+tegra124_clk_register_emc(void __iomem *base, struct device_node *np,
+ spinlock_t *lock)
{
return NULL;
}
+
+static inline bool tegra124_clk_emc_driver_available(struct clk_hw *emc_hw)
+{
+ return false;
+}
#endif

void tegra114_clock_tune_cpu_trimmers_high(void);
diff --git a/drivers/memory/tegra/Kconfig b/drivers/memory/tegra/Kconfig
index ca7077a06f4c..f5b451403c58 100644
--- a/drivers/memory/tegra/Kconfig
+++ b/drivers/memory/tegra/Kconfig
@@ -32,9 +32,10 @@ config TEGRA30_EMC
external memory.

config TEGRA124_EMC
- bool "NVIDIA Tegra124 External Memory Controller driver"
+ tristate "NVIDIA Tegra124 External Memory Controller driver"
default y
depends on TEGRA_MC && ARCH_TEGRA_124_SOC
+ select TEGRA124_CLK_EMC
help
This driver is for the External Memory Controller (EMC) found on
Tegra124 chips. The EMC controls the external DRAM on the board.
diff --git a/drivers/memory/tegra/tegra124-emc.c b/drivers/memory/tegra/tegra124-emc.c
index ee8ee39e98ed..edfbf6d6d357 100644
--- a/drivers/memory/tegra/tegra124-emc.c
+++ b/drivers/memory/tegra/tegra124-emc.c
@@ -9,16 +9,17 @@
#include <linux/clk-provider.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
+#include <linux/clk/tegra.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/io.h>
+#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/sort.h>
#include <linux/string.h>

-#include <soc/tegra/emc.h>
#include <soc/tegra/fuse.h>
#include <soc/tegra/mc.h>

@@ -562,8 +563,8 @@ static struct emc_timing *tegra_emc_find_timing(struct tegra_emc *emc,
return timing;
}

-int tegra_emc_prepare_timing_change(struct tegra_emc *emc,
- unsigned long rate)
+static int tegra_emc_prepare_timing_change(struct tegra_emc *emc,
+ unsigned long rate)
{
struct emc_timing *timing = tegra_emc_find_timing(emc, rate);
struct emc_timing *last = &emc->last_timing;
@@ -790,8 +791,8 @@ int tegra_emc_prepare_timing_change(struct tegra_emc *emc,
return 0;
}

-void tegra_emc_complete_timing_change(struct tegra_emc *emc,
- unsigned long rate)
+static void tegra_emc_complete_timing_change(struct tegra_emc *emc,
+ unsigned long rate)
{
struct emc_timing *timing = tegra_emc_find_timing(emc, rate);
struct emc_timing *last = &emc->last_timing;
@@ -987,6 +988,7 @@ static const struct of_device_id tegra_emc_of_match[] = {
{ .compatible = "nvidia,tegra132-emc" },
{}
};
+MODULE_DEVICE_TABLE(of, tegra_emc_of_match);

static struct device_node *
tegra_emc_find_node_by_ram_code(struct device_node *node, u32 ram_code)
@@ -1226,9 +1228,19 @@ static int tegra_emc_probe(struct platform_device *pdev)

platform_set_drvdata(pdev, emc);

+ tegra124_clk_set_emc_callbacks(tegra_emc_prepare_timing_change,
+ tegra_emc_complete_timing_change);
+
if (IS_ENABLED(CONFIG_DEBUG_FS))
emc_debugfs_init(&pdev->dev, emc);

+ /*
+ * Don't allow the kernel module to be unloaded. Unloading adds some
+ * extra complexity which doesn't really worth the effort in a case of
+ * this driver.
+ */
+ try_module_get(THIS_MODULE);
+
return 0;
};

@@ -1240,9 +1252,8 @@ static struct platform_driver tegra_emc_driver = {
.suppress_bind_attrs = true,
},
};
+module_platform_driver(tegra_emc_driver);

-static int tegra_emc_init(void)
-{
- return platform_driver_register(&tegra_emc_driver);
-}
-subsys_initcall(tegra_emc_init);
+MODULE_AUTHOR("Mikko Perttunen <mperttunen@xxxxxxxxxx>");
+MODULE_DESCRIPTION("NVIDIA Tegra124 EMC driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/clk/tegra.h b/include/linux/clk/tegra.h
index 3f01d43f0598..eb016fc9cc0b 100644
--- a/include/linux/clk/tegra.h
+++ b/include/linux/clk/tegra.h
@@ -136,6 +136,7 @@ extern void tegra210_clk_emc_dll_update_setting(u32 emc_dll_src_value);
extern void tegra210_clk_emc_update_setting(u32 emc_src_value);

struct clk;
+struct tegra_emc;

typedef long (tegra20_clk_emc_round_cb)(unsigned long rate,
unsigned long min_rate,
@@ -146,6 +147,13 @@ void tegra20_clk_set_emc_round_callback(tegra20_clk_emc_round_cb *round_cb,
void *cb_arg);
int tegra20_clk_prepare_emc_mc_same_freq(struct clk *emc_clk, bool same);

+typedef int (tegra124_emc_prepare_timing_change_cb)(struct tegra_emc *emc,
+ unsigned long rate);
+typedef void (tegra124_emc_complete_timing_change_cb)(struct tegra_emc *emc,
+ unsigned long rate);
+void tegra124_clk_set_emc_callbacks(tegra124_emc_prepare_timing_change_cb *prep_cb,
+ tegra124_emc_complete_timing_change_cb *complete_cb);
+
struct tegra210_clk_emc_config {
unsigned long rate;
bool same_freq;
diff --git a/include/soc/tegra/emc.h b/include/soc/tegra/emc.h
deleted file mode 100644
index 05199a97ccf4..000000000000
--- a/include/soc/tegra/emc.h
+++ /dev/null
@@ -1,16 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (c) 2014 NVIDIA Corporation. All rights reserved.
- */
-
-#ifndef __SOC_TEGRA_EMC_H__
-#define __SOC_TEGRA_EMC_H__
-
-struct tegra_emc;
-
-int tegra_emc_prepare_timing_change(struct tegra_emc *emc,
- unsigned long rate);
-void tegra_emc_complete_timing_change(struct tegra_emc *emc,
- unsigned long rate);
-
-#endif /* __SOC_TEGRA_EMC_H__ */
--
2.29.2