[PATCH v8] clk: Add Gemini SoC clock controller
Linus Walleij
linus.walleij at linaro.org
Wed Jun 21 00:59:52 PDT 2017
The Cortina Systems Gemini (SL3516/CS3516) has an on-chip clock
controller that derive all clocks from a single crystal, using some
documented and some undocumented PLLs, half dividers, counters and
gates. This is a best attempt to construct a clock driver for the
clocks so at least we can gate off unused hardware and driver the
PCI bus clock.
Acked-by: Philipp Zabel <p.zabel at pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
ChangeLog v7->v8:
- Add Philipp's Acked-by that I managed to forget.
ChangeLog v6->v7:
- Use platform device oriented memory remapping with
devm_ioremap_resource().
- Convert shouty boot message about clock frequency to a
pr_debug().
- Drop patches 1, 2 from the series as they got merged.
ChangeLog v5->v6:
- Merge the Gemini reset controller code into the clock driver
so as to resolve the conflict about what device should be
probing from the system controller. The reset portions are
copy/pasted from the driver previously merged by Philipp
Zabel.
- Split the driver in two init paths: one that executes at
CLK_OF_DECLARE_DRIVER() level to provide the basic cxo, AHB
and APB clocks, so that the system timer can start, and
another path executed for the platform device as it comes
up. The clock table is filled with -EPROBE_DEFER pointers
until the platform device probes.
ChangeLog v4->v5:
- Add a dependency on ARCH_GEMINI || COMPILE_TEST to Kconfig
- Fix the includes, remove <linux/clkdev.h>, add <linux/spinlock.h>
- Indent all defines properly.
- Remove the global clock arrays and use the pattern to allocate
a struct clk_hw_onecell_data * and fill that with the hw clocks.
- Switch everything to use struct clk_hw * everywhere.
- Look up clocks using of_clk_hw_onecell_get, add the lookup
using of_clk_add_hw_provider().
- Cut unnecessary status checks from regmap_* accessors, skip
to just checking the return value of the first access and
then assume the MMIO regmap is working fine.
- Reduce the CPU-to-AHB calculation switch() statement to a table
lookup.
ChangeLog v3->v4:
- No changes, just resending with separate DT header file.
ChangeLog v2->v3:
- Augment driver to probe directly from the system controller.
- Mike/Stephen: when you're happy with this please ACK it so I
can merge it through ARM SoC. This is needed because of
the mess of #include <dt-bindings/*> from the DT bindings
that is then used all over the DTS files.
ChangeLog v1->v2:
- Move the clock controller to be part of the syscon node. No
need for a separate child node for this.
---
drivers/clk/Kconfig | 9 +
drivers/clk/Makefile | 1 +
drivers/clk/clk-gemini.c | 458 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 468 insertions(+)
create mode 100644 drivers/clk/clk-gemini.c
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 36cfea38135f..8611b0de01a0 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -126,6 +126,15 @@ config COMMON_CLK_CS2000_CP
help
If you say yes here you get support for the CS2000 clock multiplier.
+config COMMON_CLK_GEMINI
+ bool "Clock driver for Cortina Systems Gemini SoC"
+ depends on ARCH_GEMINI || COMPILE_TEST
+ select MFD_SYSCON
+ select RESET_CONTROLLER
+ ---help---
+ This driver supports the SoC clocks on the Cortina Systems Gemini
+ platform, also known as SL3516 or CS3516.
+
config COMMON_CLK_S2MPS11
tristate "Clock driver for S2MPS1X/S5M8767 MFD"
depends on MFD_SEC_CORE || COMPILE_TEST
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index c19983afcb81..a625c002a810 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -25,6 +25,7 @@ obj-$(CONFIG_COMMON_CLK_CDCE925) += clk-cdce925.o
obj-$(CONFIG_ARCH_CLPS711X) += clk-clps711x.o
obj-$(CONFIG_COMMON_CLK_CS2000_CP) += clk-cs2000-cp.o
obj-$(CONFIG_ARCH_EFM32) += clk-efm32gg.o
+obj-$(CONFIG_COMMON_CLK_GEMINI) += clk-gemini.o
obj-$(CONFIG_ARCH_HIGHBANK) += clk-highbank.o
obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o
obj-$(CONFIG_ARCH_MB86S7X) += clk-mb86s7x.o
diff --git a/drivers/clk/clk-gemini.c b/drivers/clk/clk-gemini.c
new file mode 100644
index 000000000000..3ddd2faec674
--- /dev/null
+++ b/drivers/clk/clk-gemini.c
@@ -0,0 +1,458 @@
+/*
+ * Cortina Gemini SoC Clock Controller driver
+ * Copyright (c) 2017 Linus Walleij <linus.walleij at linaro.org>
+ */
+
+#define pr_fmt(fmt) "clk-gemini: " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/clk-provider.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/spinlock.h>
+#include <linux/reset-controller.h>
+#include <dt-bindings/reset/cortina,gemini-reset.h>
+#include <dt-bindings/clock/cortina,gemini-clock.h>
+
+/* Globally visible clocks */
+static DEFINE_SPINLOCK(gemini_clk_lock);
+
+#define GEMINI_GLOBAL_STATUS 0x04
+#define PLL_OSC_SEL BIT(30)
+#define AHBSPEED_SHIFT (15)
+#define AHBSPEED_MASK 0x07
+#define CPU_AHB_RATIO_SHIFT (18)
+#define CPU_AHB_RATIO_MASK 0x03
+
+#define GEMINI_GLOBAL_PLL_CONTROL 0x08
+
+#define GEMINI_GLOBAL_SOFT_RESET 0x0c
+
+#define GEMINI_GLOBAL_MISC_CONTROL 0x30
+#define PCI_CLK_66MHZ BIT(18)
+#define PCI_CLK_OE BIT(17)
+
+#define GEMINI_GLOBAL_CLOCK_CONTROL 0x34
+#define PCI_CLKRUN_EN BIT(16)
+#define TVC_HALFDIV_SHIFT (24)
+#define TVC_HALFDIV_MASK 0x1f
+#define SECURITY_CLK_SEL BIT(29)
+
+#define GEMINI_GLOBAL_PCI_DLL_CONTROL 0x44
+#define PCI_DLL_BYPASS BIT(31)
+#define PCI_DLL_TAP_SEL_MASK 0x1f
+
+/**
+ * struct gemini_data_data - Gemini gated clocks
+ * @bit_idx: the bit used to gate this clock in the clock register
+ * @name: the clock name
+ * @parent_name: the name of the parent clock
+ * @flags: standard clock framework flags
+ */
+struct gemini_gate_data {
+ u8 bit_idx;
+ const char *name;
+ const char *parent_name;
+ unsigned long flags;
+};
+
+/**
+ * struct clk_gemini_pci - Gemini PCI clock
+ * @hw: corresponding clock hardware entry
+ * @map: regmap to access the registers
+ * @rate: current rate
+ */
+struct clk_gemini_pci {
+ struct clk_hw hw;
+ struct regmap *map;
+ unsigned long rate;
+};
+
+/**
+ * struct gemini_reset - gemini reset controller
+ * @map: regmap to access the containing system controller
+ * @rcdev: reset controller device
+ */
+struct gemini_reset {
+ struct regmap *map;
+ struct reset_controller_dev rcdev;
+};
+
+/* Keeps track of all clocks */
+static struct clk_hw_onecell_data *gemini_clk_data;
+
+static const struct gemini_gate_data gemini_gates[] = {
+ { 1, "security-gate", "secdiv", 0 },
+ { 2, "gmac0-gate", "ahb", 0 },
+ { 3, "gmac1-gate", "ahb", 0 },
+ { 4, "sata0-gate", "ahb", 0 },
+ { 5, "sata1-gate", "ahb", 0 },
+ { 6, "usb0-gate", "ahb", 0 },
+ { 7, "usb1-gate", "ahb", 0 },
+ { 8, "ide-gate", "ahb", 0 },
+ { 9, "pci-gate", "ahb", 0 },
+ /*
+ * The DDR controller may never have a driver, but certainly must
+ * not be gated off.
+ */
+ { 10, "ddr-gate", "ahb", CLK_IS_CRITICAL },
+ /*
+ * The flash controller must be on to access NOR flash through the
+ * memory map.
+ */
+ { 11, "flash-gate", "ahb", CLK_IGNORE_UNUSED },
+ { 12, "tvc-gate", "ahb", 0 },
+ { 13, "boot-gate", "apb", 0 },
+};
+
+#define to_pciclk(_hw) container_of(_hw, struct clk_gemini_pci, hw)
+
+#define to_gemini_reset(p) container_of((p), struct gemini_reset, rcdev)
+
+static unsigned long gemini_pci_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_gemini_pci *pciclk = to_pciclk(hw);
+ u32 val;
+
+ regmap_read(pciclk->map, GEMINI_GLOBAL_MISC_CONTROL, &val);
+ if (val & PCI_CLK_66MHZ)
+ return 66000000;
+ return 33000000;
+}
+
+static long gemini_pci_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ /* We support 33 and 66 MHz */
+ if (rate < 48000000)
+ return 33000000;
+ return 66000000;
+}
+
+static int gemini_pci_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_gemini_pci *pciclk = to_pciclk(hw);
+
+ if (rate == 33000000)
+ return regmap_update_bits(pciclk->map,
+ GEMINI_GLOBAL_MISC_CONTROL,
+ PCI_CLK_66MHZ, 0);
+ if (rate == 66000000)
+ return regmap_update_bits(pciclk->map,
+ GEMINI_GLOBAL_MISC_CONTROL,
+ 0, PCI_CLK_66MHZ);
+ return -EINVAL;
+}
+
+static int gemini_pci_enable(struct clk_hw *hw)
+{
+ struct clk_gemini_pci *pciclk = to_pciclk(hw);
+
+ regmap_update_bits(pciclk->map, GEMINI_GLOBAL_CLOCK_CONTROL,
+ 0, PCI_CLKRUN_EN);
+ regmap_update_bits(pciclk->map,
+ GEMINI_GLOBAL_MISC_CONTROL,
+ 0, PCI_CLK_OE);
+ return 0;
+}
+
+static void gemini_pci_disable(struct clk_hw *hw)
+{
+ struct clk_gemini_pci *pciclk = to_pciclk(hw);
+
+ regmap_update_bits(pciclk->map,
+ GEMINI_GLOBAL_MISC_CONTROL,
+ PCI_CLK_OE, 0);
+ regmap_update_bits(pciclk->map, GEMINI_GLOBAL_CLOCK_CONTROL,
+ PCI_CLKRUN_EN, 0);
+}
+
+static int gemini_pci_is_enabled(struct clk_hw *hw)
+{
+ struct clk_gemini_pci *pciclk = to_pciclk(hw);
+ unsigned int val;
+
+ regmap_read(pciclk->map, GEMINI_GLOBAL_CLOCK_CONTROL, &val);
+ return !!(val & PCI_CLKRUN_EN);
+}
+
+static const struct clk_ops gemini_pci_clk_ops = {
+ .recalc_rate = gemini_pci_recalc_rate,
+ .round_rate = gemini_pci_round_rate,
+ .set_rate = gemini_pci_set_rate,
+ .enable = gemini_pci_enable,
+ .disable = gemini_pci_disable,
+ .is_enabled = gemini_pci_is_enabled,
+};
+
+static struct clk_hw *gemini_pci_clk_setup(const char *name,
+ const char *parent_name,
+ struct regmap *map)
+{
+ struct clk_gemini_pci *pciclk;
+ struct clk_init_data init;
+ int ret;
+
+ pciclk = kzalloc(sizeof(*pciclk), GFP_KERNEL);
+ if (!pciclk)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &gemini_pci_clk_ops;
+ init.flags = 0;
+ init.parent_names = &parent_name;
+ init.num_parents = 1;
+ pciclk->map = map;
+ pciclk->hw.init = &init;
+
+ ret = clk_hw_register(NULL, &pciclk->hw);
+ if (ret) {
+ kfree(pciclk);
+ return ERR_PTR(ret);
+ }
+
+ return &pciclk->hw;
+}
+
+/*
+ * This is a self-deasserting reset controller.
+ */
+static int gemini_reset(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct gemini_reset *gr = to_gemini_reset(rcdev);
+
+ /* Manual says to always set BIT 30 (CPU1) to 1 */
+ return regmap_write(gr->map,
+ GEMINI_GLOBAL_SOFT_RESET,
+ BIT(GEMINI_RESET_CPU1) | BIT(id));
+}
+
+static int gemini_reset_status(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct gemini_reset *gr = to_gemini_reset(rcdev);
+ u32 val;
+ int ret;
+
+ ret = regmap_read(gr->map, GEMINI_GLOBAL_SOFT_RESET, &val);
+ if (ret)
+ return ret;
+
+ return !!(val & BIT(id));
+}
+
+static const struct reset_control_ops gemini_reset_ops = {
+ .reset = gemini_reset,
+ .status = gemini_reset_status,
+};
+
+static int gemini_clk_probe(struct platform_device *pdev)
+{
+ /* Gives the fracions 1x, 1.5x, 1.85x and 2x */
+ unsigned int cpu_ahb_mult[4] = { 1, 3, 24, 2 };
+ unsigned int cpu_ahb_div[4] = { 1, 2, 13, 1 };
+ void __iomem *base;
+ struct gemini_reset *gr;
+ struct regmap *map;
+ struct clk_hw *hw;
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ unsigned int mult, div;
+ struct resource *res;
+ u32 val;
+ int ret;
+ int i;
+
+ gr = devm_kzalloc(dev, sizeof(*gr), GFP_KERNEL);
+ if (!gr)
+ return -ENOMEM;
+
+ /* Remap the system controller for the exclusive register */
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+ base = devm_ioremap_resource(dev, res);
+ if (!base) {
+ dev_err(dev, "no memory base\n");
+ return -ENODEV;
+ }
+
+ map = syscon_node_to_regmap(np);
+ if (IS_ERR(map)) {
+ dev_err(dev, "no syscon regmap\n");
+ return PTR_ERR(map);
+ }
+
+ gr->map = map;
+ gr->rcdev.owner = THIS_MODULE;
+ gr->rcdev.nr_resets = 32;
+ gr->rcdev.ops = &gemini_reset_ops;
+ gr->rcdev.of_node = np;
+
+ ret = devm_reset_controller_register(dev, &gr->rcdev);
+ if (ret) {
+ dev_err(dev, "could not register reset controller\n");
+ return ret;
+ }
+
+ /* RTC clock 32768 Hz */
+ hw = clk_hw_register_fixed_rate(NULL, "rtc", NULL, 0, 32768);
+ gemini_clk_data->hws[GEMINI_CLK_RTC] = hw;
+
+ /* CPU clock derived as a fixed ratio from the AHB clock */
+ val >>= CPU_AHB_RATIO_SHIFT;
+ val &= CPU_AHB_RATIO_MASK;
+ hw = clk_hw_register_fixed_factor(NULL, "cpu", "ahb", 0,
+ cpu_ahb_mult[val],
+ cpu_ahb_div[val]);
+ gemini_clk_data->hws[GEMINI_CLK_CPU] = hw;
+
+ /* Security clock is 1:1 or 0.75 of APB */
+ regmap_read(map, GEMINI_GLOBAL_CLOCK_CONTROL, &val);
+ if (val & SECURITY_CLK_SEL) {
+ mult = 1;
+ div = 1;
+ } else {
+ mult = 3;
+ div = 4;
+ }
+ hw = clk_hw_register_fixed_factor(NULL, "secdiv", "ahb", 0, mult, div);
+
+ /*
+ * These are the leaf gates, at boot no clocks are gated.
+ */
+ for (i = 0; i < ARRAY_SIZE(gemini_gates); i++) {
+ const struct gemini_gate_data *gd;
+
+ gd = &gemini_gates[i];
+ gemini_clk_data->hws[GEMINI_CLK_GATES + i] =
+ clk_hw_register_gate(NULL, gd->name,
+ gd->parent_name,
+ gd->flags,
+ base + GEMINI_GLOBAL_CLOCK_CONTROL,
+ gd->bit_idx,
+ CLK_GATE_SET_TO_DISABLE,
+ &gemini_clk_lock);
+ }
+
+ /*
+ * The TV Interface Controller has a 5-bit half divider register.
+ * This clock is supposed to be 27MHz as this is an exact multiple
+ * of PAL and NTSC frequencies. The register is undocumented :(
+ * FIXME: figure out the parent and how the divider works.
+ */
+ mult = 1;
+ div = ((val >> TVC_HALFDIV_SHIFT) & TVC_HALFDIV_MASK);
+ dev_dbg(dev, "TVC half divider value = %d\n", div);
+ div += 1;
+ hw = clk_hw_register_fixed_rate(NULL, "tvcdiv", "xtal", 0, 27000000);
+ gemini_clk_data->hws[GEMINI_CLK_TVC] = hw;
+
+ /* FIXME: very unclear what the parent is */
+ hw = gemini_pci_clk_setup("PCI", "xtal", map);
+ gemini_clk_data->hws[GEMINI_CLK_PCI] = hw;
+
+ /* FIXME: very unclear what the parent is */
+ hw = clk_hw_register_fixed_rate(NULL, "uart", "xtal", 0, 48000000);
+ gemini_clk_data->hws[GEMINI_CLK_UART] = hw;
+
+ return 0;
+}
+
+static const struct of_device_id gemini_clk_dt_ids[] = {
+ { .compatible = "cortina,gemini-syscon", },
+ { /* sentinel */ },
+};
+
+static struct platform_driver gemini_clk_driver = {
+ .probe = gemini_clk_probe,
+ .driver = {
+ .name = "gemini-clk",
+ .of_match_table = gemini_clk_dt_ids,
+ .suppress_bind_attrs = true,
+ },
+};
+builtin_platform_driver(gemini_clk_driver);
+
+static void __init gemini_cc_init(struct device_node *np)
+{
+ struct regmap *map;
+ struct clk_hw *hw;
+ unsigned long freq;
+ unsigned int mult, div;
+ u32 val;
+ int ret;
+ int i;
+
+ gemini_clk_data = kzalloc(sizeof(*gemini_clk_data) +
+ sizeof(*gemini_clk_data->hws) * GEMINI_NUM_CLKS,
+ GFP_KERNEL);
+ if (!gemini_clk_data)
+ return;
+
+ /*
+ * This way all clock fetched before the platform device probes,
+ * except those we assign here for early use, will be deferred.
+ */
+ for (i = 0; i < GEMINI_NUM_CLKS; i++)
+ gemini_clk_data->hws[i] = ERR_PTR(-EPROBE_DEFER);
+
+ map = syscon_node_to_regmap(np);
+ if (IS_ERR(map)) {
+ pr_err("no syscon regmap\n");
+ return;
+ }
+ /*
+ * We check that the regmap works on this very first access,
+ * but as this is an MMIO-backed regmap, subsequent regmap
+ * access is not going to fail and we skip error checks from
+ * this point.
+ */
+ ret = regmap_read(map, GEMINI_GLOBAL_STATUS, &val);
+ if (ret) {
+ pr_err("failed to read global status register\n");
+ return;
+ }
+
+ /*
+ * XTAL is the crystal oscillator, 60 or 30 MHz selected from
+ * strap pin E6
+ */
+ if (val & PLL_OSC_SEL)
+ freq = 30000000;
+ else
+ freq = 60000000;
+ hw = clk_hw_register_fixed_rate(NULL, "xtal", NULL, 0, freq);
+ pr_debug("main crystal @%lu MHz\n", freq / 1000000);
+
+ /* VCO clock derived from the crystal */
+ mult = 13 + ((val >> AHBSPEED_SHIFT) & AHBSPEED_MASK);
+ div = 2;
+ /* If we run on 30 MHz crystal we have to multiply with two */
+ if (val & PLL_OSC_SEL)
+ mult *= 2;
+ hw = clk_hw_register_fixed_factor(NULL, "vco", "xtal", 0, mult, div);
+
+ /* The AHB clock is always 1/3 of the VCO */
+ hw = clk_hw_register_fixed_factor(NULL, "ahb", "vco", 0, 1, 3);
+ gemini_clk_data->hws[GEMINI_CLK_AHB] = hw;
+
+ /* The APB clock is always 1/6 of the AHB */
+ hw = clk_hw_register_fixed_factor(NULL, "apb", "ahb", 0, 1, 6);
+ gemini_clk_data->hws[GEMINI_CLK_APB] = hw;
+
+ /* Register the clocks to be accessed by the device tree */
+ gemini_clk_data->num = GEMINI_NUM_CLKS;
+ of_clk_add_hw_provider(np, of_clk_hw_onecell_get, gemini_clk_data);
+}
+CLK_OF_DECLARE_DRIVER(gemini_cc, "cortina,gemini-syscon", gemini_cc_init);
--
2.9.4
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