linux-stable/drivers/clk/qcom/clk-rcg.h
Bjorn Andersson 703db1f5da clk: qcom: rcg2: Cache CFG register updates for parked RCGs
As GDSCs are turned on and off some associated clocks are momentarily
enabled for house keeping purposes. For this, and similar, purposes the
"shared RCGs" will park the RCG on a source clock which is known to be
available.
When the RCG is parked, a safe clock source will be selected and
committed, then the original source would be written back and upon enable
the change back to the unparked source would be committed.

But starting with SM8350 this fails, as the value in CFG is committed by
the GDSC handshake and without a ticking parent the GDSC enablement will
time out.

This becomes a concrete problem if the runtime supended state of a
device includes disabling such rcg's parent clock. As the device
attempts to power up the domain again the rcg will fail to enable and
hence the GDSC enablement will fail, preventing the device from
returning from the suspended state.

This can be seen in e.g. the display stack during probe on SM8350.

To avoid this problem, the software needs to ensure that the RCG is
configured to a active parent clock while it is disabled. This is done
by caching the CFG register content while the shared RCG is parked on
this safe source.

Writes to M, N and D registers are committed as they are requested. New
helpers for get_parent() and recalc_rate() are extracted from their
previous implementations and __clk_rcg2_configure() is modified to allow
it to operate on the cached value.

Fixes: 7ef6f11887 ("clk: qcom: Configure the RCGs to a safe source as needed")
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20220426212136.1543984-1-bjorn.andersson@linaro.org
2022-05-19 16:42:30 -05:00

189 lines
4.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (c) 2013, 2018, The Linux Foundation. All rights reserved. */
#ifndef __QCOM_CLK_RCG_H__
#define __QCOM_CLK_RCG_H__
#include <linux/clk-provider.h>
#include "clk-regmap.h"
#define F(f, s, h, m, n) { (f), (s), (2 * (h) - 1), (m), (n) }
struct freq_tbl {
unsigned long freq;
u8 src;
u8 pre_div;
u16 m;
u16 n;
};
/**
* struct mn - M/N:D counter
* @mnctr_en_bit: bit to enable mn counter
* @mnctr_reset_bit: bit to assert mn counter reset
* @mnctr_mode_shift: lowest bit of mn counter mode field
* @n_val_shift: lowest bit of n value field
* @m_val_shift: lowest bit of m value field
* @width: number of bits in m/n/d values
* @reset_in_cc: true if the mnctr_reset_bit is in the CC register
*/
struct mn {
u8 mnctr_en_bit;
u8 mnctr_reset_bit;
u8 mnctr_mode_shift;
#define MNCTR_MODE_DUAL 0x2
#define MNCTR_MODE_MASK 0x3
u8 n_val_shift;
u8 m_val_shift;
u8 width;
bool reset_in_cc;
};
/**
* struct pre_div - pre-divider
* @pre_div_shift: lowest bit of pre divider field
* @pre_div_width: number of bits in predivider
*/
struct pre_div {
u8 pre_div_shift;
u8 pre_div_width;
};
/**
* struct src_sel - source selector
* @src_sel_shift: lowest bit of source selection field
* @parent_map: map from software's parent index to hardware's src_sel field
*/
struct src_sel {
u8 src_sel_shift;
#define SRC_SEL_MASK 0x7
const struct parent_map *parent_map;
};
/**
* struct clk_rcg - root clock generator
*
* @ns_reg: NS register
* @md_reg: MD register
* @mn: mn counter
* @p: pre divider
* @s: source selector
* @freq_tbl: frequency table
* @clkr: regmap clock handle
* @lock: register lock
*/
struct clk_rcg {
u32 ns_reg;
u32 md_reg;
struct mn mn;
struct pre_div p;
struct src_sel s;
const struct freq_tbl *freq_tbl;
struct clk_regmap clkr;
};
extern const struct clk_ops clk_rcg_ops;
extern const struct clk_ops clk_rcg_floor_ops;
extern const struct clk_ops clk_rcg_bypass_ops;
extern const struct clk_ops clk_rcg_bypass2_ops;
extern const struct clk_ops clk_rcg_pixel_ops;
extern const struct clk_ops clk_rcg_esc_ops;
extern const struct clk_ops clk_rcg_lcc_ops;
#define to_clk_rcg(_hw) container_of(to_clk_regmap(_hw), struct clk_rcg, clkr)
/**
* struct clk_dyn_rcg - root clock generator with glitch free mux
*
* @mux_sel_bit: bit to switch glitch free mux
* @ns_reg: NS0 and NS1 register
* @md_reg: MD0 and MD1 register
* @bank_reg: register to XOR @mux_sel_bit into to switch glitch free mux
* @mn: mn counter (banked)
* @s: source selector (banked)
* @freq_tbl: frequency table
* @clkr: regmap clock handle
* @lock: register lock
*/
struct clk_dyn_rcg {
u32 ns_reg[2];
u32 md_reg[2];
u32 bank_reg;
u8 mux_sel_bit;
struct mn mn[2];
struct pre_div p[2];
struct src_sel s[2];
const struct freq_tbl *freq_tbl;
struct clk_regmap clkr;
};
extern const struct clk_ops clk_dyn_rcg_ops;
#define to_clk_dyn_rcg(_hw) \
container_of(to_clk_regmap(_hw), struct clk_dyn_rcg, clkr)
/**
* struct clk_rcg2 - root clock generator
*
* @cmd_rcgr: corresponds to *_CMD_RCGR
* @mnd_width: number of bits in m/n/d values
* @hid_width: number of bits in half integer divider
* @safe_src_index: safe src index value
* @parent_map: map from software's parent index to hardware's src_sel field
* @freq_tbl: frequency table
* @clkr: regmap clock handle
* @cfg_off: defines the cfg register offset from the CMD_RCGR + CFG_REG
* @parked_cfg: cached value of the CFG register for parked RCGs
*/
struct clk_rcg2 {
u32 cmd_rcgr;
u8 mnd_width;
u8 hid_width;
u8 safe_src_index;
const struct parent_map *parent_map;
const struct freq_tbl *freq_tbl;
struct clk_regmap clkr;
u8 cfg_off;
u32 parked_cfg;
};
#define to_clk_rcg2(_hw) container_of(to_clk_regmap(_hw), struct clk_rcg2, clkr)
struct clk_rcg2_gfx3d {
u8 div;
struct clk_rcg2 rcg;
struct clk_hw **hws;
};
#define to_clk_rcg2_gfx3d(_hw) \
container_of(to_clk_rcg2(_hw), struct clk_rcg2_gfx3d, rcg)
extern const struct clk_ops clk_rcg2_ops;
extern const struct clk_ops clk_rcg2_floor_ops;
extern const struct clk_ops clk_edp_pixel_ops;
extern const struct clk_ops clk_byte_ops;
extern const struct clk_ops clk_byte2_ops;
extern const struct clk_ops clk_pixel_ops;
extern const struct clk_ops clk_gfx3d_ops;
extern const struct clk_ops clk_rcg2_shared_ops;
extern const struct clk_ops clk_dp_ops;
struct clk_rcg_dfs_data {
struct clk_rcg2 *rcg;
struct clk_init_data *init;
};
#define DEFINE_RCG_DFS(r) \
{ .rcg = &r, .init = &r##_init }
extern int qcom_cc_register_rcg_dfs(struct regmap *regmap,
const struct clk_rcg_dfs_data *rcgs,
size_t len);
#endif