OpenCloudOS-Kernel/drivers/clk/baikal-t1/clk-ccu-pll.c

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clk: Add Baikal-T1 CCU PLLs driver Baikal-T1 is supposed to be supplied with a high-frequency external oscillator. But in order to create signals suitable for each IP-block embedded into the SoC the oscillator output is primarily connected to a set of CCU PLLs. There are five of them to create clocks for the MIPS P5600 cores, an embedded DDR controller, SATA, Ethernet and PCIe domains. The last three domains though named by the biggest system interfaces in fact include nearly all of the rest SoC peripherals. Each of the PLLs is based on True Circuits TSMC CLN28HPM IP-core with an interface wrapper (so called safe PLL' clocks switcher) to simplify the PLL configuration procedure. This driver creates the of-based hardware clocks to use them then in the corresponding subsystems. In order to simplify the driver code we split the functionality up into the PLLs clocks operations and hardware clocks declaration/registration procedures. Even though the PLLs are based on the same IP-core, they may have some differences. In particular, some CCU PLLs support the output clock change without gating them (like CPU or PCIe PLLs), while the others don't, some CCU PLLs are critical and aren't supposed to be gated. In order to cover all of these cases the hardware clocks driver is designed with an info-descriptor pattern. So there are special static descriptors declared for each PLL, which is then used to create a hardware clock with proper operations. Additionally debugfs-files are provided for each PLL' field to make sure the implemented rate-PLLs-dividers calculation algorithm is correct. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200526222056.18072-4-Sergey.Semin@baikalelectronics.ru [sboyd@kernel.org: Silence sparse warning about initializing structs with NULL vs. integer] Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2020-05-27 06:20:55 +08:00
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
*
* Authors:
* Serge Semin <Sergey.Semin@baikalelectronics.ru>
* Dmitry Dunaev <dmitry.dunaev@baikalelectronics.ru>
*
* Baikal-T1 CCU PLL clocks driver
*/
#define pr_fmt(fmt) "bt1-ccu-pll: " fmt
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/clk-provider.h>
#include <linux/mfd/syscon.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/ioport.h>
#include <linux/regmap.h>
#include <dt-bindings/clock/bt1-ccu.h>
#include "ccu-pll.h"
#define CCU_CPU_PLL_BASE 0x000
#define CCU_SATA_PLL_BASE 0x008
#define CCU_DDR_PLL_BASE 0x010
#define CCU_PCIE_PLL_BASE 0x018
#define CCU_ETH_PLL_BASE 0x020
#define CCU_PLL_INFO(_id, _name, _pname, _base, _flags) \
{ \
.id = _id, \
.name = _name, \
.parent_name = _pname, \
.base = _base, \
.flags = _flags \
}
#define CCU_PLL_NUM ARRAY_SIZE(pll_info)
struct ccu_pll_info {
unsigned int id;
const char *name;
const char *parent_name;
unsigned int base;
unsigned long flags;
};
/*
* Alas we have to mark all PLLs as critical. CPU and DDR PLLs are sources of
* CPU cores and DDR controller reference clocks, due to which they obviously
* shouldn't be ever gated. SATA and PCIe PLLs are the parents of APB-bus and
* DDR controller AXI-bus clocks. If they are gated the system will be
* unusable. Moreover disabling SATA and Ethernet PLLs causes automatic reset
* of the corresponding subsystems. So until we aren't ready to re-initialize
* all the devices consuming those PLLs, they will be marked as critical too.
clk: Add Baikal-T1 CCU PLLs driver Baikal-T1 is supposed to be supplied with a high-frequency external oscillator. But in order to create signals suitable for each IP-block embedded into the SoC the oscillator output is primarily connected to a set of CCU PLLs. There are five of them to create clocks for the MIPS P5600 cores, an embedded DDR controller, SATA, Ethernet and PCIe domains. The last three domains though named by the biggest system interfaces in fact include nearly all of the rest SoC peripherals. Each of the PLLs is based on True Circuits TSMC CLN28HPM IP-core with an interface wrapper (so called safe PLL' clocks switcher) to simplify the PLL configuration procedure. This driver creates the of-based hardware clocks to use them then in the corresponding subsystems. In order to simplify the driver code we split the functionality up into the PLLs clocks operations and hardware clocks declaration/registration procedures. Even though the PLLs are based on the same IP-core, they may have some differences. In particular, some CCU PLLs support the output clock change without gating them (like CPU or PCIe PLLs), while the others don't, some CCU PLLs are critical and aren't supposed to be gated. In order to cover all of these cases the hardware clocks driver is designed with an info-descriptor pattern. So there are special static descriptors declared for each PLL, which is then used to create a hardware clock with proper operations. Additionally debugfs-files are provided for each PLL' field to make sure the implemented rate-PLLs-dividers calculation algorithm is correct. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200526222056.18072-4-Sergey.Semin@baikalelectronics.ru [sboyd@kernel.org: Silence sparse warning about initializing structs with NULL vs. integer] Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2020-05-27 06:20:55 +08:00
*/
static const struct ccu_pll_info pll_info[] = {
CCU_PLL_INFO(CCU_CPU_PLL, "cpu_pll", "ref_clk", CCU_CPU_PLL_BASE,
CLK_IS_CRITICAL),
CCU_PLL_INFO(CCU_SATA_PLL, "sata_pll", "ref_clk", CCU_SATA_PLL_BASE,
CLK_IS_CRITICAL | CLK_SET_RATE_GATE),
CCU_PLL_INFO(CCU_DDR_PLL, "ddr_pll", "ref_clk", CCU_DDR_PLL_BASE,
CLK_IS_CRITICAL | CLK_SET_RATE_GATE),
CCU_PLL_INFO(CCU_PCIE_PLL, "pcie_pll", "ref_clk", CCU_PCIE_PLL_BASE,
CLK_IS_CRITICAL),
CCU_PLL_INFO(CCU_ETH_PLL, "eth_pll", "ref_clk", CCU_ETH_PLL_BASE,
CLK_IS_CRITICAL | CLK_SET_RATE_GATE)
clk: Add Baikal-T1 CCU PLLs driver Baikal-T1 is supposed to be supplied with a high-frequency external oscillator. But in order to create signals suitable for each IP-block embedded into the SoC the oscillator output is primarily connected to a set of CCU PLLs. There are five of them to create clocks for the MIPS P5600 cores, an embedded DDR controller, SATA, Ethernet and PCIe domains. The last three domains though named by the biggest system interfaces in fact include nearly all of the rest SoC peripherals. Each of the PLLs is based on True Circuits TSMC CLN28HPM IP-core with an interface wrapper (so called safe PLL' clocks switcher) to simplify the PLL configuration procedure. This driver creates the of-based hardware clocks to use them then in the corresponding subsystems. In order to simplify the driver code we split the functionality up into the PLLs clocks operations and hardware clocks declaration/registration procedures. Even though the PLLs are based on the same IP-core, they may have some differences. In particular, some CCU PLLs support the output clock change without gating them (like CPU or PCIe PLLs), while the others don't, some CCU PLLs are critical and aren't supposed to be gated. In order to cover all of these cases the hardware clocks driver is designed with an info-descriptor pattern. So there are special static descriptors declared for each PLL, which is then used to create a hardware clock with proper operations. Additionally debugfs-files are provided for each PLL' field to make sure the implemented rate-PLLs-dividers calculation algorithm is correct. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200526222056.18072-4-Sergey.Semin@baikalelectronics.ru [sboyd@kernel.org: Silence sparse warning about initializing structs with NULL vs. integer] Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2020-05-27 06:20:55 +08:00
};
struct ccu_pll_data {
struct device_node *np;
struct regmap *sys_regs;
struct ccu_pll *plls[CCU_PLL_NUM];
};
static struct ccu_pll *ccu_pll_find_desc(struct ccu_pll_data *data,
unsigned int clk_id)
{
struct ccu_pll *pll;
int idx;
for (idx = 0; idx < CCU_PLL_NUM; ++idx) {
pll = data->plls[idx];
if (pll && pll->id == clk_id)
return pll;
}
return ERR_PTR(-EINVAL);
}
static struct ccu_pll_data *ccu_pll_create_data(struct device_node *np)
{
struct ccu_pll_data *data;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return ERR_PTR(-ENOMEM);
data->np = np;
return data;
}
static void ccu_pll_free_data(struct ccu_pll_data *data)
{
kfree(data);
}
static int ccu_pll_find_sys_regs(struct ccu_pll_data *data)
{
data->sys_regs = syscon_node_to_regmap(data->np->parent);
if (IS_ERR(data->sys_regs)) {
pr_err("Failed to find syscon regs for '%s'\n",
of_node_full_name(data->np));
return PTR_ERR(data->sys_regs);
}
return 0;
}
static struct clk_hw *ccu_pll_of_clk_hw_get(struct of_phandle_args *clkspec,
void *priv)
{
struct ccu_pll_data *data = priv;
struct ccu_pll *pll;
unsigned int clk_id;
clk_id = clkspec->args[0];
pll = ccu_pll_find_desc(data, clk_id);
if (IS_ERR(pll)) {
pr_info("Invalid PLL clock ID %d specified\n", clk_id);
return ERR_CAST(pll);
}
return ccu_pll_get_clk_hw(pll);
}
static int ccu_pll_clk_register(struct ccu_pll_data *data)
{
int idx, ret;
for (idx = 0; idx < CCU_PLL_NUM; ++idx) {
const struct ccu_pll_info *info = &pll_info[idx];
struct ccu_pll_init_data init = {0};
init.id = info->id;
init.name = info->name;
init.parent_name = info->parent_name;
init.base = info->base;
init.sys_regs = data->sys_regs;
init.np = data->np;
init.flags = info->flags;
data->plls[idx] = ccu_pll_hw_register(&init);
if (IS_ERR(data->plls[idx])) {
ret = PTR_ERR(data->plls[idx]);
pr_err("Couldn't register PLL hw '%s'\n",
init.name);
goto err_hw_unregister;
}
}
ret = of_clk_add_hw_provider(data->np, ccu_pll_of_clk_hw_get, data);
if (ret) {
pr_err("Couldn't register PLL provider of '%s'\n",
of_node_full_name(data->np));
goto err_hw_unregister;
}
return 0;
err_hw_unregister:
for (--idx; idx >= 0; --idx)
ccu_pll_hw_unregister(data->plls[idx]);
return ret;
}
static __init void ccu_pll_init(struct device_node *np)
{
struct ccu_pll_data *data;
int ret;
data = ccu_pll_create_data(np);
if (IS_ERR(data))
return;
ret = ccu_pll_find_sys_regs(data);
if (ret)
goto err_free_data;
ret = ccu_pll_clk_register(data);
if (ret)
goto err_free_data;
return;
err_free_data:
ccu_pll_free_data(data);
}
CLK_OF_DECLARE(ccu_pll, "baikal,bt1-ccu-pll", ccu_pll_init);