diff options
| -rw-r--r-- | drivers/usb/dwc3/core.c | 41 | ||||
| -rw-r--r-- | drivers/usb/dwc3/core.h | 3 |
2 files changed, 44 insertions, 0 deletions
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index ed5d0d16f78..6e0876d2c45 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -30,6 +30,7 @@ #include <linux/usb/ch9.h> #include <linux/usb/gadget.h> #include <linux/bitfield.h> +#include <linux/math64.h> #include "core.h" #include "gadget.h" @@ -37,6 +38,8 @@ #include "linux-compat.h" +#define NSEC_PER_SEC 1000000000L + static LIST_HEAD(dwc3_list); /* -------------------------------------------------------------------------- */ @@ -128,6 +131,8 @@ static void dwc3_frame_length_adjustment(struct dwc3 *dwc, u32 fladj) static void dwc3_ref_clk_period(struct dwc3 *dwc) { unsigned long period; + unsigned long fladj; + unsigned long decr; unsigned long rate; u32 reg; @@ -138,6 +143,7 @@ static void dwc3_ref_clk_period(struct dwc3 *dwc) period = NSEC_PER_SEC / rate; } else if (dwc->ref_clk_per) { period = dwc->ref_clk_per; + rate = NSEC_PER_SEC / period; } else { return; } @@ -146,6 +152,41 @@ static void dwc3_ref_clk_period(struct dwc3 *dwc) reg &= ~DWC3_GUCTL_REFCLKPER_MASK; reg |= FIELD_PREP(DWC3_GUCTL_REFCLKPER_MASK, period); dwc3_writel(dwc->regs, DWC3_GUCTL, reg); + + if (dwc->revision <= DWC3_REVISION_250A) + return; + + /* + * The calculation below is + * + * 125000 * (NSEC_PER_SEC / (rate * period) - 1) + * + * but rearranged for fixed-point arithmetic. The division must be + * 64-bit because 125000 * NSEC_PER_SEC doesn't fit in 32 bits (and + * neither does rate * period). + * + * Note that rate * period ~= NSEC_PER_SECOND, minus the number of + * nanoseconds of error caused by the truncation which happened during + * the division when calculating rate or period (whichever one was + * derived from the other). We first calculate the relative error, then + * scale it to units of 8 ppm. + */ + fladj = div64_u64(125000ULL * NSEC_PER_SEC, (u64)rate * period); + fladj -= 125000; + + /* + * The documented 240MHz constant is scaled by 2 to get PLS1 as well. + */ + decr = 480000000 / rate; + + reg = dwc3_readl(dwc->regs, DWC3_GFLADJ); + reg &= ~DWC3_GFLADJ_REFCLK_FLADJ_MASK + & ~DWC3_GFLADJ_240MHZDECR + & ~DWC3_GFLADJ_240MHZDECR_PLS1; + reg |= FIELD_PREP(DWC3_GFLADJ_REFCLK_FLADJ_MASK, fladj) + | FIELD_PREP(DWC3_GFLADJ_240MHZDECR, decr >> 1) + | FIELD_PREP(DWC3_GFLADJ_240MHZDECR_PLS1, decr & 1); + dwc3_writel(dwc->regs, DWC3_GFLADJ, reg); } /** diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index b4a7d9e52bc..532746dd88d 100644 --- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -248,6 +248,9 @@ /* Global Frame Length Adjustment Register */ #define DWC3_GFLADJ_30MHZ_SDBND_SEL (1 << 7) #define DWC3_GFLADJ_30MHZ_MASK 0x3f +#define DWC3_GFLADJ_REFCLK_FLADJ_MASK GENMASK(21, 8) +#define DWC3_GFLADJ_240MHZDECR GENMASK(30, 24) +#define DWC3_GFLADJ_240MHZDECR_PLS1 BIT(31) /* Global User Control Register*/ #define DWC3_GUCTL_REFCLKPER_MASK 0xffc00000 |