From cb4f4949b1c76f29ca804d6ecd879a2e84c88afc Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Tue, 2 Apr 2019 14:50:50 +0200 Subject: clk: at91: allow configuring peripheral PCR layout The PCR register actually changed layout for each SoC. By chance, this didn't have impact on sama5d[2-4] support but since sama5d3, PID is seven bits wide and sama5d4 and sama5d2 don't have DIV. For the DT backward compatibility, keep the layout as is. Signed-off-by: Alexandre Belloni Signed-off-by: Stephen Boyd --- include/linux/clk/at91_pmc.h | 3 --- 1 file changed, 3 deletions(-) (limited to 'include/linux/clk') diff --git a/include/linux/clk/at91_pmc.h b/include/linux/clk/at91_pmc.h index 931ab05f771d..b97b8dcbffe6 100644 --- a/include/linux/clk/at91_pmc.h +++ b/include/linux/clk/at91_pmc.h @@ -191,9 +191,6 @@ #define AT91_PMC_PCR_GCKCSS_MASK (0x7 << AT91_PMC_PCR_GCKCSS_OFFSET) #define AT91_PMC_PCR_GCKCSS(n) ((n) << AT91_PMC_PCR_GCKCSS_OFFSET) /* GCK Clock Source Selection */ #define AT91_PMC_PCR_CMD (0x1 << 12) /* Command (read=0, write=1) */ -#define AT91_PMC_PCR_DIV_OFFSET 16 -#define AT91_PMC_PCR_DIV_MASK (0x3 << AT91_PMC_PCR_DIV_OFFSET) -#define AT91_PMC_PCR_DIV(n) ((n) << AT91_PMC_PCR_DIV_OFFSET) /* Divisor Value */ #define AT91_PMC_PCR_GCKDIV_OFFSET 20 #define AT91_PMC_PCR_GCKDIV_MASK (0xff << AT91_PMC_PCR_GCKDIV_OFFSET) #define AT91_PMC_PCR_GCKDIV(n) ((n) << AT91_PMC_PCR_GCKDIV_OFFSET) /* Generated Clock Divisor Value */ -- cgit v1.2.3 From e4cfb823bd71c785fe482e4d7491ef04ac561a7d Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Tue, 2 Apr 2019 14:50:51 +0200 Subject: clk: at91: allow configuring generated PCR layout The PCR register layout for GCLKCSS is changing for the future SoCs, allow configuring it. Signed-off-by: Alexandre Belloni Signed-off-by: Stephen Boyd --- drivers/clk/at91/clk-generated.c | 48 +++++++++++++++++++++------------------- drivers/clk/at91/dt-compat.c | 3 ++- drivers/clk/at91/pmc.h | 1 + drivers/clk/at91/sama5d2.c | 1 + include/linux/clk/at91_pmc.h | 7 +----- 5 files changed, 30 insertions(+), 30 deletions(-) (limited to 'include/linux/clk') diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c index 66e7f7baf958..5f18847965c1 100644 --- a/drivers/clk/at91/clk-generated.c +++ b/drivers/clk/at91/clk-generated.c @@ -11,6 +11,7 @@ * */ +#include #include #include #include @@ -31,6 +32,7 @@ struct clk_generated { spinlock_t *lock; u32 id; u32 gckdiv; + const struct clk_pcr_layout *layout; u8 parent_id; bool audio_pll_allowed; }; @@ -47,14 +49,14 @@ static int clk_generated_enable(struct clk_hw *hw) __func__, gck->gckdiv, gck->parent_id); spin_lock_irqsave(gck->lock, flags); - regmap_write(gck->regmap, AT91_PMC_PCR, - (gck->id & AT91_PMC_PCR_PID_MASK)); - regmap_update_bits(gck->regmap, AT91_PMC_PCR, - AT91_PMC_PCR_GCKDIV_MASK | AT91_PMC_PCR_GCKCSS_MASK | - AT91_PMC_PCR_CMD | AT91_PMC_PCR_GCKEN, - AT91_PMC_PCR_GCKCSS(gck->parent_id) | - AT91_PMC_PCR_CMD | - AT91_PMC_PCR_GCKDIV(gck->gckdiv) | + regmap_write(gck->regmap, gck->layout->offset, + (gck->id & gck->layout->pid_mask)); + regmap_update_bits(gck->regmap, gck->layout->offset, + AT91_PMC_PCR_GCKDIV_MASK | gck->layout->gckcss_mask | + gck->layout->cmd | AT91_PMC_PCR_GCKEN, + field_prep(gck->layout->gckcss_mask, gck->parent_id) | + gck->layout->cmd | + FIELD_PREP(AT91_PMC_PCR_GCKDIV_MASK, gck->gckdiv) | AT91_PMC_PCR_GCKEN); spin_unlock_irqrestore(gck->lock, flags); return 0; @@ -66,11 +68,11 @@ static void clk_generated_disable(struct clk_hw *hw) unsigned long flags; spin_lock_irqsave(gck->lock, flags); - regmap_write(gck->regmap, AT91_PMC_PCR, - (gck->id & AT91_PMC_PCR_PID_MASK)); - regmap_update_bits(gck->regmap, AT91_PMC_PCR, - AT91_PMC_PCR_CMD | AT91_PMC_PCR_GCKEN, - AT91_PMC_PCR_CMD); + regmap_write(gck->regmap, gck->layout->offset, + (gck->id & gck->layout->pid_mask)); + regmap_update_bits(gck->regmap, gck->layout->offset, + gck->layout->cmd | AT91_PMC_PCR_GCKEN, + gck->layout->cmd); spin_unlock_irqrestore(gck->lock, flags); } @@ -81,9 +83,9 @@ static int clk_generated_is_enabled(struct clk_hw *hw) unsigned int status; spin_lock_irqsave(gck->lock, flags); - regmap_write(gck->regmap, AT91_PMC_PCR, - (gck->id & AT91_PMC_PCR_PID_MASK)); - regmap_read(gck->regmap, AT91_PMC_PCR, &status); + regmap_write(gck->regmap, gck->layout->offset, + (gck->id & gck->layout->pid_mask)); + regmap_read(gck->regmap, gck->layout->offset, &status); spin_unlock_irqrestore(gck->lock, flags); return status & AT91_PMC_PCR_GCKEN ? 1 : 0; @@ -259,19 +261,18 @@ static void clk_generated_startup(struct clk_generated *gck) unsigned long flags; spin_lock_irqsave(gck->lock, flags); - regmap_write(gck->regmap, AT91_PMC_PCR, - (gck->id & AT91_PMC_PCR_PID_MASK)); - regmap_read(gck->regmap, AT91_PMC_PCR, &tmp); + regmap_write(gck->regmap, gck->layout->offset, + (gck->id & gck->layout->pid_mask)); + regmap_read(gck->regmap, gck->layout->offset, &tmp); spin_unlock_irqrestore(gck->lock, flags); - gck->parent_id = (tmp & AT91_PMC_PCR_GCKCSS_MASK) - >> AT91_PMC_PCR_GCKCSS_OFFSET; - gck->gckdiv = (tmp & AT91_PMC_PCR_GCKDIV_MASK) - >> AT91_PMC_PCR_GCKDIV_OFFSET; + gck->parent_id = field_get(gck->layout->gckcss_mask, tmp); + gck->gckdiv = FIELD_GET(AT91_PMC_PCR_GCKDIV_MASK, tmp); } struct clk_hw * __init at91_clk_register_generated(struct regmap *regmap, spinlock_t *lock, + const struct clk_pcr_layout *layout, const char *name, const char **parent_names, u8 num_parents, u8 id, bool pll_audio, const struct clk_range *range) @@ -298,6 +299,7 @@ at91_clk_register_generated(struct regmap *regmap, spinlock_t *lock, gck->lock = lock; gck->range = *range; gck->audio_pll_allowed = pll_audio; + gck->layout = layout; clk_generated_startup(gck); hw = &gck->hw; diff --git a/drivers/clk/at91/dt-compat.c b/drivers/clk/at91/dt-compat.c index aa09072f36db..aa1754eac59f 100644 --- a/drivers/clk/at91/dt-compat.c +++ b/drivers/clk/at91/dt-compat.c @@ -154,7 +154,8 @@ static void __init of_sama5d2_clk_generated_setup(struct device_node *np) id == GCK_ID_CLASSD)) pll_audio = true; - hw = at91_clk_register_generated(regmap, &pmc_pcr_lock, name, + hw = at91_clk_register_generated(regmap, &pmc_pcr_lock, + &dt_pcr_layout, name, parent_names, num_parents, id, pll_audio, &range); if (IS_ERR(hw)) diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h index 616c04588093..4027306b904c 100644 --- a/drivers/clk/at91/pmc.h +++ b/drivers/clk/at91/pmc.h @@ -116,6 +116,7 @@ at91_clk_register_audio_pll_pmc(struct regmap *regmap, const char *name, struct clk_hw * __init at91_clk_register_generated(struct regmap *regmap, spinlock_t *lock, + const struct clk_pcr_layout *layout, const char *name, const char **parent_names, u8 num_parents, u8 id, bool pll_audio, const struct clk_range *range); diff --git a/drivers/clk/at91/sama5d2.c b/drivers/clk/at91/sama5d2.c index 9d128bd60fee..096156850e08 100644 --- a/drivers/clk/at91/sama5d2.c +++ b/drivers/clk/at91/sama5d2.c @@ -305,6 +305,7 @@ static void __init sama5d2_pmc_setup(struct device_node *np) parent_names[5] = "audiopll_pmcck"; for (i = 0; i < ARRAY_SIZE(sama5d2_gck); i++) { hw = at91_clk_register_generated(regmap, &pmc_pcr_lock, + &sama5d2_pcr_layout, sama5d2_gck[i].n, parent_names, 6, sama5d2_gck[i].id, diff --git a/include/linux/clk/at91_pmc.h b/include/linux/clk/at91_pmc.h index b97b8dcbffe6..31f00ebf1315 100644 --- a/include/linux/clk/at91_pmc.h +++ b/include/linux/clk/at91_pmc.h @@ -187,13 +187,8 @@ #define AT91_PMC_PCR 0x10c /* Peripheral Control Register [some SAM9 and SAMA5] */ #define AT91_PMC_PCR_PID_MASK 0x3f -#define AT91_PMC_PCR_GCKCSS_OFFSET 8 -#define AT91_PMC_PCR_GCKCSS_MASK (0x7 << AT91_PMC_PCR_GCKCSS_OFFSET) -#define AT91_PMC_PCR_GCKCSS(n) ((n) << AT91_PMC_PCR_GCKCSS_OFFSET) /* GCK Clock Source Selection */ #define AT91_PMC_PCR_CMD (0x1 << 12) /* Command (read=0, write=1) */ -#define AT91_PMC_PCR_GCKDIV_OFFSET 20 -#define AT91_PMC_PCR_GCKDIV_MASK (0xff << AT91_PMC_PCR_GCKDIV_OFFSET) -#define AT91_PMC_PCR_GCKDIV(n) ((n) << AT91_PMC_PCR_GCKDIV_OFFSET) /* Generated Clock Divisor Value */ +#define AT91_PMC_PCR_GCKDIV_MASK GENMASK(27, 20) #define AT91_PMC_PCR_EN (0x1 << 28) /* Enable */ #define AT91_PMC_PCR_GCKEN (0x1 << 29) /* GCK Enable */ -- cgit v1.2.3 From e5be537064dd36129a724c65820e5fc2daebd5f4 Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Tue, 2 Apr 2019 14:50:53 +0200 Subject: clk: at91: master: Add sam9x60 support The sam9x60 cpu clock is located at a different offset but is otherwise similar to the master clock. Signed-off-by: Alexandre Belloni Signed-off-by: Stephen Boyd --- drivers/clk/at91/clk-master.c | 8 +++++--- drivers/clk/at91/pmc.h | 1 + include/linux/clk/at91_pmc.h | 2 ++ 3 files changed, 8 insertions(+), 3 deletions(-) (limited to 'include/linux/clk') diff --git a/drivers/clk/at91/clk-master.c b/drivers/clk/at91/clk-master.c index eb53b4a8fab6..12b5bf4cc7bb 100644 --- a/drivers/clk/at91/clk-master.c +++ b/drivers/clk/at91/clk-master.c @@ -29,6 +29,7 @@ struct clk_master { struct regmap *regmap; const struct clk_master_layout *layout; const struct clk_master_characteristics *characteristics; + u32 mckr; }; static inline bool clk_master_ready(struct regmap *regmap) @@ -69,7 +70,7 @@ static unsigned long clk_master_recalc_rate(struct clk_hw *hw, master->characteristics; unsigned int mckr; - regmap_read(master->regmap, AT91_PMC_MCKR, &mckr); + regmap_read(master->regmap, master->layout->offset, &mckr); mckr &= layout->mask; pres = (mckr >> layout->pres_shift) & MASTER_PRES_MASK; @@ -95,7 +96,7 @@ static u8 clk_master_get_parent(struct clk_hw *hw) struct clk_master *master = to_clk_master(hw); unsigned int mckr; - regmap_read(master->regmap, AT91_PMC_MCKR, &mckr); + regmap_read(master->regmap, master->layout->offset, &mckr); return mckr & AT91_PMC_CSS; } @@ -147,13 +148,14 @@ at91_clk_register_master(struct regmap *regmap, return hw; } - const struct clk_master_layout at91rm9200_master_layout = { .mask = 0x31F, .pres_shift = 2, + .offset = AT91_PMC_MCKR, }; const struct clk_master_layout at91sam9x5_master_layout = { .mask = 0x373, .pres_shift = 4, + .offset = AT91_PMC_MCKR, }; diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h index 44345e4ab1c9..4a30c20f17f1 100644 --- a/drivers/clk/at91/pmc.h +++ b/drivers/clk/at91/pmc.h @@ -38,6 +38,7 @@ struct clk_range { #define CLK_RANGE(MIN, MAX) {.min = MIN, .max = MAX,} struct clk_master_layout { + u32 offset; u32 mask; u8 pres_shift; }; diff --git a/include/linux/clk/at91_pmc.h b/include/linux/clk/at91_pmc.h index 31f00ebf1315..0c53f26ae3d3 100644 --- a/include/linux/clk/at91_pmc.h +++ b/include/linux/clk/at91_pmc.h @@ -74,6 +74,8 @@ #define AT91_PMC_USBDIV_4 (2 << 28) #define AT91_PMC_USB96M (1 << 28) /* Divider by 2 Enable (PLLB only) */ +#define AT91_PMC_CPU_CKR 0x28 /* CPU Clock Register */ + #define AT91_PMC_MCKR 0x30 /* Master Clock Register */ #define AT91_PMC_CSS (3 << 0) /* Master Clock Selection */ #define AT91_PMC_CSS_SLOW (0 << 0) -- cgit v1.2.3 From 7b9487a9a5c41ce0ff4f6ca74652e99541bd51c3 Mon Sep 17 00:00:00 2001 From: Paul Walmsley Date: Tue, 30 Apr 2019 13:50:58 -0700 Subject: clk: analogbits: add Wide-Range PLL library Add common library code for the Analog Bits Wide-Range PLL (WRPLL) IP block, as implemented in TSMC CLN28HPC. There is no bus interface or register target associated with this PLL. This library is intended to be used by drivers for IP blocks that expose registers connected to the PLL configuration and status signals. Based on code originally written by Wesley Terpstra : https://github.com/riscv/riscv-linux/commit/999529edf517ed75b56659d456d221b2ee56bb60 This version incorporates several changes requested by Stephen Boyd . Signed-off-by: Paul Walmsley Signed-off-by: Paul Walmsley Cc: Wesley Terpstra Cc: Palmer Dabbelt Cc: Michael Turquette Cc: Stephen Boyd Cc: Megan Wachs Cc: linux-clk@vger.kernel.org Cc: linux-kernel@vger.kernel.org [sboyd@kernel.org: Fix some const issues] Signed-off-by: Stephen Boyd --- MAINTAINERS | 6 + drivers/clk/Kconfig | 2 + drivers/clk/Makefile | 1 + drivers/clk/analogbits/Kconfig | 2 + drivers/clk/analogbits/Makefile | 3 + drivers/clk/analogbits/wrpll-cln28hpc.c | 364 ++++++++++++++++++++++++++ include/linux/clk/analogbits-wrpll-cln28hpc.h | 79 ++++++ 7 files changed, 457 insertions(+) create mode 100644 drivers/clk/analogbits/Kconfig create mode 100644 drivers/clk/analogbits/Makefile create mode 100644 drivers/clk/analogbits/wrpll-cln28hpc.c create mode 100644 include/linux/clk/analogbits-wrpll-cln28hpc.h (limited to 'include/linux/clk') diff --git a/MAINTAINERS b/MAINTAINERS index 09f43f1bdd15..98e1d15549f5 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -960,6 +960,12 @@ F: drivers/iio/adc/ltc2497* X: drivers/iio/*/adjd* F: drivers/staging/iio/*/ad* +ANALOGBITS PLL LIBRARIES +M: Paul Walmsley +S: Supported +F: drivers/clk/analogbits/* +F: include/linux/clk/analogbits* + ANDES ARCHITECTURE M: Greentime Hu M: Vincent Chen diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig index e705aab9e38b..8a0e77f791ab 100644 --- a/drivers/clk/Kconfig +++ b/drivers/clk/Kconfig @@ -1,3 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0 config CLKDEV_LOOKUP bool @@ -297,6 +298,7 @@ config COMMON_CLK_FIXED_MMIO Support for Memory Mapped IO Fixed clocks source "drivers/clk/actions/Kconfig" +source "drivers/clk/analogbits/Kconfig" source "drivers/clk/bcm/Kconfig" source "drivers/clk/hisilicon/Kconfig" source "drivers/clk/imgtec/Kconfig" diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 1db133652f0c..091ee1d8af65 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -64,6 +64,7 @@ obj-$(CONFIG_COMMON_CLK_XGENE) += clk-xgene.o # please keep this section sorted lexicographically by directory path name obj-y += actions/ +obj-y += analogbits/ obj-$(CONFIG_COMMON_CLK_AT91) += at91/ obj-$(CONFIG_ARCH_ARTPEC) += axis/ obj-$(CONFIG_ARC_PLAT_AXS10X) += axs10x/ diff --git a/drivers/clk/analogbits/Kconfig b/drivers/clk/analogbits/Kconfig new file mode 100644 index 000000000000..b5fd60c7f136 --- /dev/null +++ b/drivers/clk/analogbits/Kconfig @@ -0,0 +1,2 @@ +config CLK_ANALOGBITS_WRPLL_CLN28HPC + bool diff --git a/drivers/clk/analogbits/Makefile b/drivers/clk/analogbits/Makefile new file mode 100644 index 000000000000..bf017447451e --- /dev/null +++ b/drivers/clk/analogbits/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0 + +obj-$(CONFIG_CLK_ANALOGBITS_WRPLL_CLN28HPC) += wrpll-cln28hpc.o diff --git a/drivers/clk/analogbits/wrpll-cln28hpc.c b/drivers/clk/analogbits/wrpll-cln28hpc.c new file mode 100644 index 000000000000..776ead319ae9 --- /dev/null +++ b/drivers/clk/analogbits/wrpll-cln28hpc.c @@ -0,0 +1,364 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018-2019 SiFive, Inc. + * Wesley Terpstra + * Paul Walmsley + * + * This library supports configuration parsing and reprogramming of + * the CLN28HPC variant of the Analog Bits Wide Range PLL. The + * intention is for this library to be reusable for any device that + * integrates this PLL; thus the register structure and programming + * details are expected to be provided by a separate IP block driver. + * + * The bulk of this code is primarily useful for clock configurations + * that must operate at arbitrary rates, as opposed to clock configurations + * that are restricted by software or manufacturer guidance to a small, + * pre-determined set of performance points. + * + * References: + * - Analog Bits "Wide Range PLL Datasheet", version 2015.10.01 + * - SiFive FU540-C000 Manual v1p0, Chapter 7 "Clocking and Reset" + * https://static.dev.sifive.com/FU540-C000-v1.0.pdf + */ + +#include +#include +#include +#include +#include + +/* MIN_INPUT_FREQ: minimum input clock frequency, in Hz (Fref_min) */ +#define MIN_INPUT_FREQ 7000000 + +/* MAX_INPUT_FREQ: maximum input clock frequency, in Hz (Fref_max) */ +#define MAX_INPUT_FREQ 600000000 + +/* MIN_POST_DIVIDE_REF_FREQ: minimum post-divider reference frequency, in Hz */ +#define MIN_POST_DIVR_FREQ 7000000 + +/* MAX_POST_DIVIDE_REF_FREQ: maximum post-divider reference frequency, in Hz */ +#define MAX_POST_DIVR_FREQ 200000000 + +/* MIN_VCO_FREQ: minimum VCO frequency, in Hz (Fvco_min) */ +#define MIN_VCO_FREQ 2400000000UL + +/* MAX_VCO_FREQ: maximum VCO frequency, in Hz (Fvco_max) */ +#define MAX_VCO_FREQ 4800000000ULL + +/* MAX_DIVQ_DIVISOR: maximum output divisor. Selected by DIVQ = 6 */ +#define MAX_DIVQ_DIVISOR 64 + +/* MAX_DIVR_DIVISOR: maximum reference divisor. Selected by DIVR = 63 */ +#define MAX_DIVR_DIVISOR 64 + +/* MAX_LOCK_US: maximum PLL lock time, in microseconds (tLOCK_max) */ +#define MAX_LOCK_US 70 + +/* + * ROUND_SHIFT: number of bits to shift to avoid precision loss in the rounding + * algorithm + */ +#define ROUND_SHIFT 20 + +/* + * Private functions + */ + +/** + * __wrpll_calc_filter_range() - determine PLL loop filter bandwidth + * @post_divr_freq: input clock rate after the R divider + * + * Select the value to be presented to the PLL RANGE input signals, based + * on the input clock frequency after the post-R-divider @post_divr_freq. + * This code follows the recommendations in the PLL datasheet for filter + * range selection. + * + * Return: The RANGE value to be presented to the PLL configuration inputs, + * or a negative return code upon error. + */ +static int __wrpll_calc_filter_range(unsigned long post_divr_freq) +{ + if (post_divr_freq < MIN_POST_DIVR_FREQ || + post_divr_freq > MAX_POST_DIVR_FREQ) { + WARN(1, "%s: post-divider reference freq out of range: %lu", + __func__, post_divr_freq); + return -ERANGE; + } + + switch (post_divr_freq) { + case 0 ... 10999999: + return 1; + case 11000000 ... 17999999: + return 2; + case 18000000 ... 29999999: + return 3; + case 30000000 ... 49999999: + return 4; + case 50000000 ... 79999999: + return 5; + case 80000000 ... 129999999: + return 6; + } + + return 7; +} + +/** + * __wrpll_calc_fbdiv() - return feedback fixed divide value + * @c: ptr to a struct wrpll_cfg record to read from + * + * The internal feedback path includes a fixed by-two divider; the + * external feedback path does not. Return the appropriate divider + * value (2 or 1) depending on whether internal or external feedback + * is enabled. This code doesn't test for invalid configurations + * (e.g. both or neither of WRPLL_FLAGS_*_FEEDBACK are set); it relies + * on the caller to do so. + * + * Context: Any context. Caller must protect the memory pointed to by + * @c from simultaneous modification. + * + * Return: 2 if internal feedback is enabled or 1 if external feedback + * is enabled. + */ +static u8 __wrpll_calc_fbdiv(const struct wrpll_cfg *c) +{ + return (c->flags & WRPLL_FLAGS_INT_FEEDBACK_MASK) ? 2 : 1; +} + +/** + * __wrpll_calc_divq() - determine DIVQ based on target PLL output clock rate + * @target_rate: target PLL output clock rate + * @vco_rate: pointer to a u64 to store the computed VCO rate into + * + * Determine a reasonable value for the PLL Q post-divider, based on the + * target output rate @target_rate for the PLL. Along with returning the + * computed Q divider value as the return value, this function stores the + * desired target VCO rate into the variable pointed to by @vco_rate. + * + * Context: Any context. Caller must protect the memory pointed to by + * @vco_rate from simultaneous access or modification. + * + * Return: a positive integer DIVQ value to be programmed into the hardware + * upon success, or 0 upon error (since 0 is an invalid DIVQ value) + */ +static u8 __wrpll_calc_divq(u32 target_rate, u64 *vco_rate) +{ + u64 s; + u8 divq = 0; + + if (!vco_rate) { + WARN_ON(1); + goto wcd_out; + } + + s = div_u64(MAX_VCO_FREQ, target_rate); + if (s <= 1) { + divq = 1; + *vco_rate = MAX_VCO_FREQ; + } else if (s > MAX_DIVQ_DIVISOR) { + divq = ilog2(MAX_DIVQ_DIVISOR); + *vco_rate = MIN_VCO_FREQ; + } else { + divq = ilog2(s); + *vco_rate = (u64)target_rate << divq; + } + +wcd_out: + return divq; +} + +/** + * __wrpll_update_parent_rate() - update PLL data when parent rate changes + * @c: ptr to a struct wrpll_cfg record to write PLL data to + * @parent_rate: PLL input refclk rate (pre-R-divider) + * + * Pre-compute some data used by the PLL configuration algorithm when + * the PLL's reference clock rate changes. The intention is to avoid + * computation when the parent rate remains constant - expected to be + * the common case. + * + * Returns: 0 upon success or -ERANGE if the reference clock rate is + * out of range. + */ +static int __wrpll_update_parent_rate(struct wrpll_cfg *c, + unsigned long parent_rate) +{ + u8 max_r_for_parent; + + if (parent_rate > MAX_INPUT_FREQ || parent_rate < MIN_POST_DIVR_FREQ) + return -ERANGE; + + c->parent_rate = parent_rate; + max_r_for_parent = div_u64(parent_rate, MIN_POST_DIVR_FREQ); + c->max_r = min_t(u8, MAX_DIVR_DIVISOR, max_r_for_parent); + + c->init_r = DIV_ROUND_UP_ULL(parent_rate, MAX_POST_DIVR_FREQ); + + return 0; +} + +/** + * wrpll_configure() - compute PLL configuration for a target rate + * @c: ptr to a struct wrpll_cfg record to write into + * @target_rate: target PLL output clock rate (post-Q-divider) + * @parent_rate: PLL input refclk rate (pre-R-divider) + * + * Compute the appropriate PLL signal configuration values and store + * in PLL context @c. PLL reprogramming is not glitchless, so the + * caller should switch any downstream logic to a different clock + * source or clock-gate it before presenting these values to the PLL + * configuration signals. + * + * The caller must pass this function a pre-initialized struct + * wrpll_cfg record: either initialized to zero (with the + * exception of the .name and .flags fields) or read from the PLL. + * + * Context: Any context. Caller must protect the memory pointed to by @c + * from simultaneous access or modification. + * + * Return: 0 upon success; anything else upon failure. + */ +int wrpll_configure_for_rate(struct wrpll_cfg *c, u32 target_rate, + unsigned long parent_rate) +{ + unsigned long ratio; + u64 target_vco_rate, delta, best_delta, f_pre_div, vco, vco_pre; + u32 best_f, f, post_divr_freq; + u8 fbdiv, divq, best_r, r; + int range; + + if (c->flags == 0) { + WARN(1, "%s called with uninitialized PLL config", __func__); + return -EINVAL; + } + + /* Initialize rounding data if it hasn't been initialized already */ + if (parent_rate != c->parent_rate) { + if (__wrpll_update_parent_rate(c, parent_rate)) { + pr_err("%s: PLL input rate is out of range\n", + __func__); + return -ERANGE; + } + } + + c->flags &= ~WRPLL_FLAGS_RESET_MASK; + + /* Put the PLL into bypass if the user requests the parent clock rate */ + if (target_rate == parent_rate) { + c->flags |= WRPLL_FLAGS_BYPASS_MASK; + return 0; + } + + c->flags &= ~WRPLL_FLAGS_BYPASS_MASK; + + /* Calculate the Q shift and target VCO rate */ + divq = __wrpll_calc_divq(target_rate, &target_vco_rate); + if (!divq) + return -1; + c->divq = divq; + + /* Precalculate the pre-Q divider target ratio */ + ratio = div64_u64((target_vco_rate << ROUND_SHIFT), parent_rate); + + fbdiv = __wrpll_calc_fbdiv(c); + best_r = 0; + best_f = 0; + best_delta = MAX_VCO_FREQ; + + /* + * Consider all values for R which land within + * [MIN_POST_DIVR_FREQ, MAX_POST_DIVR_FREQ]; prefer smaller R + */ + for (r = c->init_r; r <= c->max_r; ++r) { + f_pre_div = ratio * r; + f = (f_pre_div + (1 << ROUND_SHIFT)) >> ROUND_SHIFT; + f >>= (fbdiv - 1); + + post_divr_freq = div_u64(parent_rate, r); + vco_pre = fbdiv * post_divr_freq; + vco = vco_pre * f; + + /* Ensure rounding didn't take us out of range */ + if (vco > target_vco_rate) { + --f; + vco = vco_pre * f; + } else if (vco < MIN_VCO_FREQ) { + ++f; + vco = vco_pre * f; + } + + delta = abs(target_rate - vco); + if (delta < best_delta) { + best_delta = delta; + best_r = r; + best_f = f; + } + } + + c->divr = best_r - 1; + c->divf = best_f - 1; + + post_divr_freq = div_u64(parent_rate, best_r); + + /* Pick the best PLL jitter filter */ + range = __wrpll_calc_filter_range(post_divr_freq); + if (range < 0) + return range; + c->range = range; + + return 0; +} + +/** + * wrpll_calc_output_rate() - calculate the PLL's target output rate + * @c: ptr to a struct wrpll_cfg record to read from + * @parent_rate: PLL refclk rate + * + * Given a pointer to the PLL's current input configuration @c and the + * PLL's input reference clock rate @parent_rate (before the R + * pre-divider), calculate the PLL's output clock rate (after the Q + * post-divider). + * + * Context: Any context. Caller must protect the memory pointed to by @c + * from simultaneous modification. + * + * Return: the PLL's output clock rate, in Hz. The return value from + * this function is intended to be convenient to pass directly + * to the Linux clock framework; thus there is no explicit + * error return value. + */ +unsigned long wrpll_calc_output_rate(const struct wrpll_cfg *c, + unsigned long parent_rate) +{ + u8 fbdiv; + u64 n; + + if (c->flags & WRPLL_FLAGS_EXT_FEEDBACK_MASK) { + WARN(1, "external feedback mode not yet supported"); + return ULONG_MAX; + } + + fbdiv = __wrpll_calc_fbdiv(c); + n = parent_rate * fbdiv * (c->divf + 1); + n = div_u64(n, c->divr + 1); + n >>= c->divq; + + return n; +} + +/** + * wrpll_calc_max_lock_us() - return the time for the PLL to lock + * @c: ptr to a struct wrpll_cfg record to read from + * + * Return the minimum amount of time (in microseconds) that the caller + * must wait after reprogramming the PLL to ensure that it is locked + * to the input frequency and stable. This is likely to depend on the DIVR + * value; this is under discussion with the manufacturer. + * + * Return: the minimum amount of time the caller must wait for the PLL + * to lock (in microseconds) + */ +unsigned int wrpll_calc_max_lock_us(const struct wrpll_cfg *c) +{ + return MAX_LOCK_US; +} diff --git a/include/linux/clk/analogbits-wrpll-cln28hpc.h b/include/linux/clk/analogbits-wrpll-cln28hpc.h new file mode 100644 index 000000000000..03279097e138 --- /dev/null +++ b/include/linux/clk/analogbits-wrpll-cln28hpc.h @@ -0,0 +1,79 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2018-2019 SiFive, Inc. + * Wesley Terpstra + * Paul Walmsley + */ + +#ifndef __LINUX_CLK_ANALOGBITS_WRPLL_CLN28HPC_H +#define __LINUX_CLK_ANALOGBITS_WRPLL_CLN28HPC_H + +#include + +/* DIVQ_VALUES: number of valid DIVQ values */ +#define DIVQ_VALUES 6 + +/* + * Bit definitions for struct wrpll_cfg.flags + * + * WRPLL_FLAGS_BYPASS_FLAG: if set, the PLL is either in bypass, or should be + * programmed to enter bypass + * WRPLL_FLAGS_RESET_FLAG: if set, the PLL is in reset + * WRPLL_FLAGS_INT_FEEDBACK_FLAG: if set, the PLL is configured for internal + * feedback mode + * WRPLL_FLAGS_EXT_FEEDBACK_FLAG: if set, the PLL is configured for external + * feedback mode (not yet supported by this driver) + */ +#define WRPLL_FLAGS_BYPASS_SHIFT 0 +#define WRPLL_FLAGS_BYPASS_MASK BIT(WRPLL_FLAGS_BYPASS_SHIFT) +#define WRPLL_FLAGS_RESET_SHIFT 1 +#define WRPLL_FLAGS_RESET_MASK BIT(WRPLL_FLAGS_RESET_SHIFT) +#define WRPLL_FLAGS_INT_FEEDBACK_SHIFT 2 +#define WRPLL_FLAGS_INT_FEEDBACK_MASK BIT(WRPLL_FLAGS_INT_FEEDBACK_SHIFT) +#define WRPLL_FLAGS_EXT_FEEDBACK_SHIFT 3 +#define WRPLL_FLAGS_EXT_FEEDBACK_MASK BIT(WRPLL_FLAGS_EXT_FEEDBACK_SHIFT) + +/** + * struct wrpll_cfg - WRPLL configuration values + * @divr: reference divider value (6 bits), as presented to the PLL signals + * @divf: feedback divider value (9 bits), as presented to the PLL signals + * @divq: output divider value (3 bits), as presented to the PLL signals + * @flags: PLL configuration flags. See above for more information + * @range: PLL loop filter range. See below for more information + * @output_rate_cache: cached output rates, swept across DIVQ + * @parent_rate: PLL refclk rate for which values are valid + * @max_r: maximum possible R divider value, given @parent_rate + * @init_r: initial R divider value to start the search from + * + * @divr, @divq, @divq, @range represent what the PLL expects to see + * on its input signals. Thus @divr and @divf are the actual divisors + * minus one. @divq is a power-of-two divider; for example, 1 = + * divide-by-2 and 6 = divide-by-64. 0 is an invalid @divq value. + * + * When initially passing a struct wrpll_cfg record, the + * record should be zero-initialized with the exception of the @flags + * field. The only flag bits that need to be set are either + * WRPLL_FLAGS_INT_FEEDBACK or WRPLL_FLAGS_EXT_FEEDBACK. + */ +struct wrpll_cfg { + u8 divr; + u8 divq; + u8 range; + u8 flags; + u16 divf; +/* private: */ + u32 output_rate_cache[DIVQ_VALUES]; + unsigned long parent_rate; + u8 max_r; + u8 init_r; +}; + +int wrpll_configure_for_rate(struct wrpll_cfg *c, u32 target_rate, + unsigned long parent_rate); + +unsigned int wrpll_calc_max_lock_us(const struct wrpll_cfg *c); + +unsigned long wrpll_calc_output_rate(const struct wrpll_cfg *c, + unsigned long parent_rate); + +#endif /* __LINUX_CLK_ANALOGBITS_WRPLL_CLN28HPC_H */ -- cgit v1.2.3