linux-stable/drivers/clk/qcom/gdsc.c
Bjorn Andersson 37416e5549 clk: qcom: gdsc: Handle GDSC regulator supplies
Certain GDSCs, such as the GPU_GX on MSM8996, requires that the upstream
regulator supply is powered in order to be turned on.

It's not guaranteed that the bootloader will leave these supplies on and
the driver core will attempt to enable any GDSCs before allowing the
individual drivers to probe defer on the PMIC regulator driver not yet
being present.

So the gdsc driver needs to be made aware of supplying regulators and
probe defer on their absence, and it needs to enable and disable the
regulator accordingly.

Voltage adjustments of the supplying regulator are deferred to the
client drivers themselves.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lkml.kernel.org/r/20200417070044.1376212-2-bjorn.andersson@linaro.org
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2020-05-14 14:23:38 -07:00

435 lines
9.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2015, 2017-2018, The Linux Foundation. All rights reserved.
*/
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/pm_domain.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
#include "gdsc.h"
#define PWR_ON_MASK BIT(31)
#define EN_REST_WAIT_MASK GENMASK_ULL(23, 20)
#define EN_FEW_WAIT_MASK GENMASK_ULL(19, 16)
#define CLK_DIS_WAIT_MASK GENMASK_ULL(15, 12)
#define SW_OVERRIDE_MASK BIT(2)
#define HW_CONTROL_MASK BIT(1)
#define SW_COLLAPSE_MASK BIT(0)
#define GMEM_CLAMP_IO_MASK BIT(0)
#define GMEM_RESET_MASK BIT(4)
/* CFG_GDSCR */
#define GDSC_POWER_UP_COMPLETE BIT(16)
#define GDSC_POWER_DOWN_COMPLETE BIT(15)
#define CFG_GDSCR_OFFSET 0x4
/* Wait 2^n CXO cycles between all states. Here, n=2 (4 cycles). */
#define EN_REST_WAIT_VAL (0x2 << 20)
#define EN_FEW_WAIT_VAL (0x8 << 16)
#define CLK_DIS_WAIT_VAL (0x2 << 12)
#define RETAIN_MEM BIT(14)
#define RETAIN_PERIPH BIT(13)
#define TIMEOUT_US 500
#define domain_to_gdsc(domain) container_of(domain, struct gdsc, pd)
enum gdsc_status {
GDSC_OFF,
GDSC_ON
};
/* Returns 1 if GDSC status is status, 0 if not, and < 0 on error */
static int gdsc_check_status(struct gdsc *sc, enum gdsc_status status)
{
unsigned int reg;
u32 val;
int ret;
if (sc->flags & POLL_CFG_GDSCR)
reg = sc->gdscr + CFG_GDSCR_OFFSET;
else if (sc->gds_hw_ctrl)
reg = sc->gds_hw_ctrl;
else
reg = sc->gdscr;
ret = regmap_read(sc->regmap, reg, &val);
if (ret)
return ret;
if (sc->flags & POLL_CFG_GDSCR) {
switch (status) {
case GDSC_ON:
return !!(val & GDSC_POWER_UP_COMPLETE);
case GDSC_OFF:
return !!(val & GDSC_POWER_DOWN_COMPLETE);
}
}
switch (status) {
case GDSC_ON:
return !!(val & PWR_ON_MASK);
case GDSC_OFF:
return !(val & PWR_ON_MASK);
}
return -EINVAL;
}
static int gdsc_hwctrl(struct gdsc *sc, bool en)
{
u32 val = en ? HW_CONTROL_MASK : 0;
return regmap_update_bits(sc->regmap, sc->gdscr, HW_CONTROL_MASK, val);
}
static int gdsc_poll_status(struct gdsc *sc, enum gdsc_status status)
{
ktime_t start;
start = ktime_get();
do {
if (gdsc_check_status(sc, status))
return 0;
} while (ktime_us_delta(ktime_get(), start) < TIMEOUT_US);
if (gdsc_check_status(sc, status))
return 0;
return -ETIMEDOUT;
}
static int gdsc_toggle_logic(struct gdsc *sc, enum gdsc_status status)
{
int ret;
u32 val = (status == GDSC_ON) ? 0 : SW_COLLAPSE_MASK;
if (status == GDSC_ON && sc->rsupply) {
ret = regulator_enable(sc->rsupply);
if (ret < 0)
return ret;
}
ret = regmap_update_bits(sc->regmap, sc->gdscr, SW_COLLAPSE_MASK, val);
if (ret)
return ret;
/* If disabling votable gdscs, don't poll on status */
if ((sc->flags & VOTABLE) && status == GDSC_OFF) {
/*
* Add a short delay here to ensure that an enable
* right after it was disabled does not put it in an
* unknown state
*/
udelay(TIMEOUT_US);
return 0;
}
if (sc->gds_hw_ctrl) {
/*
* The gds hw controller asserts/de-asserts the status bit soon
* after it receives a power on/off request from a master.
* The controller then takes around 8 xo cycles to start its
* internal state machine and update the status bit. During
* this time, the status bit does not reflect the true status
* of the core.
* Add a delay of 1 us between writing to the SW_COLLAPSE bit
* and polling the status bit.
*/
udelay(1);
}
ret = gdsc_poll_status(sc, status);
WARN(ret, "%s status stuck at 'o%s'", sc->pd.name, status ? "ff" : "n");
if (!ret && status == GDSC_OFF && sc->rsupply) {
ret = regulator_disable(sc->rsupply);
if (ret < 0)
return ret;
}
return ret;
}
static inline int gdsc_deassert_reset(struct gdsc *sc)
{
int i;
for (i = 0; i < sc->reset_count; i++)
sc->rcdev->ops->deassert(sc->rcdev, sc->resets[i]);
return 0;
}
static inline int gdsc_assert_reset(struct gdsc *sc)
{
int i;
for (i = 0; i < sc->reset_count; i++)
sc->rcdev->ops->assert(sc->rcdev, sc->resets[i]);
return 0;
}
static inline void gdsc_force_mem_on(struct gdsc *sc)
{
int i;
u32 mask = RETAIN_MEM | RETAIN_PERIPH;
for (i = 0; i < sc->cxc_count; i++)
regmap_update_bits(sc->regmap, sc->cxcs[i], mask, mask);
}
static inline void gdsc_clear_mem_on(struct gdsc *sc)
{
int i;
u32 mask = RETAIN_MEM | RETAIN_PERIPH;
for (i = 0; i < sc->cxc_count; i++)
regmap_update_bits(sc->regmap, sc->cxcs[i], mask, 0);
}
static inline void gdsc_deassert_clamp_io(struct gdsc *sc)
{
regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
GMEM_CLAMP_IO_MASK, 0);
}
static inline void gdsc_assert_clamp_io(struct gdsc *sc)
{
regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
GMEM_CLAMP_IO_MASK, 1);
}
static inline void gdsc_assert_reset_aon(struct gdsc *sc)
{
regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
GMEM_RESET_MASK, 1);
udelay(1);
regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
GMEM_RESET_MASK, 0);
}
static int gdsc_enable(struct generic_pm_domain *domain)
{
struct gdsc *sc = domain_to_gdsc(domain);
int ret;
if (sc->pwrsts == PWRSTS_ON)
return gdsc_deassert_reset(sc);
if (sc->flags & SW_RESET) {
gdsc_assert_reset(sc);
udelay(1);
gdsc_deassert_reset(sc);
}
if (sc->flags & CLAMP_IO) {
if (sc->flags & AON_RESET)
gdsc_assert_reset_aon(sc);
gdsc_deassert_clamp_io(sc);
}
ret = gdsc_toggle_logic(sc, GDSC_ON);
if (ret)
return ret;
if (sc->pwrsts & PWRSTS_OFF)
gdsc_force_mem_on(sc);
/*
* If clocks to this power domain were already on, they will take an
* additional 4 clock cycles to re-enable after the power domain is
* enabled. Delay to account for this. A delay is also needed to ensure
* clocks are not enabled within 400ns of enabling power to the
* memories.
*/
udelay(1);
/* Turn on HW trigger mode if supported */
if (sc->flags & HW_CTRL) {
ret = gdsc_hwctrl(sc, true);
if (ret)
return ret;
/*
* Wait for the GDSC to go through a power down and
* up cycle. In case a firmware ends up polling status
* bits for the gdsc, it might read an 'on' status before
* the GDSC can finish the power cycle.
* We wait 1us before returning to ensure the firmware
* can't immediately poll the status bits.
*/
udelay(1);
}
return 0;
}
static int gdsc_disable(struct generic_pm_domain *domain)
{
struct gdsc *sc = domain_to_gdsc(domain);
int ret;
if (sc->pwrsts == PWRSTS_ON)
return gdsc_assert_reset(sc);
/* Turn off HW trigger mode if supported */
if (sc->flags & HW_CTRL) {
ret = gdsc_hwctrl(sc, false);
if (ret < 0)
return ret;
/*
* Wait for the GDSC to go through a power down and
* up cycle. In case we end up polling status
* bits for the gdsc before the power cycle is completed
* it might read an 'on' status wrongly.
*/
udelay(1);
ret = gdsc_poll_status(sc, GDSC_ON);
if (ret)
return ret;
}
if (sc->pwrsts & PWRSTS_OFF)
gdsc_clear_mem_on(sc);
ret = gdsc_toggle_logic(sc, GDSC_OFF);
if (ret)
return ret;
if (sc->flags & CLAMP_IO)
gdsc_assert_clamp_io(sc);
return 0;
}
static int gdsc_init(struct gdsc *sc)
{
u32 mask, val;
int on, ret;
/*
* Disable HW trigger: collapse/restore occur based on registers writes.
* Disable SW override: Use hardware state-machine for sequencing.
* Configure wait time between states.
*/
mask = HW_CONTROL_MASK | SW_OVERRIDE_MASK |
EN_REST_WAIT_MASK | EN_FEW_WAIT_MASK | CLK_DIS_WAIT_MASK;
val = EN_REST_WAIT_VAL | EN_FEW_WAIT_VAL | CLK_DIS_WAIT_VAL;
ret = regmap_update_bits(sc->regmap, sc->gdscr, mask, val);
if (ret)
return ret;
/* Force gdsc ON if only ON state is supported */
if (sc->pwrsts == PWRSTS_ON) {
ret = gdsc_toggle_logic(sc, GDSC_ON);
if (ret)
return ret;
}
on = gdsc_check_status(sc, GDSC_ON);
if (on < 0)
return on;
/*
* Votable GDSCs can be ON due to Vote from other masters.
* If a Votable GDSC is ON, make sure we have a Vote.
*/
if ((sc->flags & VOTABLE) && on)
gdsc_enable(&sc->pd);
/* If ALWAYS_ON GDSCs are not ON, turn them ON */
if (sc->flags & ALWAYS_ON) {
if (!on)
gdsc_enable(&sc->pd);
on = true;
sc->pd.flags |= GENPD_FLAG_ALWAYS_ON;
}
if (on || (sc->pwrsts & PWRSTS_RET))
gdsc_force_mem_on(sc);
else
gdsc_clear_mem_on(sc);
if (!sc->pd.power_off)
sc->pd.power_off = gdsc_disable;
if (!sc->pd.power_on)
sc->pd.power_on = gdsc_enable;
pm_genpd_init(&sc->pd, NULL, !on);
return 0;
}
int gdsc_register(struct gdsc_desc *desc,
struct reset_controller_dev *rcdev, struct regmap *regmap)
{
int i, ret;
struct genpd_onecell_data *data;
struct device *dev = desc->dev;
struct gdsc **scs = desc->scs;
size_t num = desc->num;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->domains = devm_kcalloc(dev, num, sizeof(*data->domains),
GFP_KERNEL);
if (!data->domains)
return -ENOMEM;
for (i = 0; i < num; i++) {
if (!scs[i] || !scs[i]->supply)
continue;
scs[i]->rsupply = devm_regulator_get(dev, scs[i]->supply);
if (IS_ERR(scs[i]->rsupply))
return PTR_ERR(scs[i]->rsupply);
}
data->num_domains = num;
for (i = 0; i < num; i++) {
if (!scs[i])
continue;
scs[i]->regmap = regmap;
scs[i]->rcdev = rcdev;
ret = gdsc_init(scs[i]);
if (ret)
return ret;
data->domains[i] = &scs[i]->pd;
}
/* Add subdomains */
for (i = 0; i < num; i++) {
if (!scs[i])
continue;
if (scs[i]->parent)
pm_genpd_add_subdomain(scs[i]->parent, &scs[i]->pd);
}
return of_genpd_add_provider_onecell(dev->of_node, data);
}
void gdsc_unregister(struct gdsc_desc *desc)
{
int i;
struct device *dev = desc->dev;
struct gdsc **scs = desc->scs;
size_t num = desc->num;
/* Remove subdomains */
for (i = 0; i < num; i++) {
if (!scs[i])
continue;
if (scs[i]->parent)
pm_genpd_remove_subdomain(scs[i]->parent, &scs[i]->pd);
}
of_genpd_del_provider(dev->of_node);
}