linux-kernel - RE: [PATCH 2/5] soc: fsl: handle RCPM errata A-008646 on SoC LS1021A

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Message-ID: <AM6PR04MB5413AC535051641B4DEFBB83F13B0@AM6PR04MB5413.eurprd04.prod.outlook.com>
Date:   Tue, 22 Sep 2020 02:16:45 +0000
From:   Ran Wang <ran.wang_1@....com>
To:     Leo Li <leoyang.li@....com>, Rob Herring <robh+dt@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>
CC:     "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Biwen Li <biwen.li@....com>
Subject: RE: [PATCH 2/5] soc: fsl: handle RCPM errata A-008646 on SoC LS1021A

Hi Leo

Tuesday, September 22, 2020 6:43 AM, Leo Li wrote:
> 
> 
> > -----Original Message-----
> > From: Ran Wang <ran.wang_1@....com>
> > Sent: Wednesday, September 16, 2020 3:18 AM
> > To: Leo Li <leoyang.li@....com>; Rob Herring <robh+dt@...nel.org>;
> > Shawn Guo <shawnguo@...nel.org>
> > Cc: linuxppc-dev@...ts.ozlabs.org;
> > linux-arm-kernel@...ts.infradead.org;
> > devicetree@...r.kernel.org; linux-kernel@...r.kernel.org; Biwen Li
> > <biwen.li@....com>; Ran Wang <ran.wang_1@....com>
> > Subject: [PATCH 2/5] soc: fsl: handle RCPM errata A-008646 on SoC
> > LS1021A
> >
> > From: Biwen Li <biwen.li@....com>
> >
> > Description:
> > 	- Reading configuration register RCPM_IPPDEXPCR1
> > 	  always return zero
> >
> > Workaround:
> > 	- Save register RCPM_IPPDEXPCR1's value to
> > 	  register SCFG_SPARECR8.(uboot's psci also
> > 	  need reading value from the register SCFG_SPARECR8
> > 	  to set register RCPM_IPPDEXPCR1)
> >
> > Impact:
> > 	- FlexTimer module will cannot wakeup system in
> Will not..
> Also it will be better to merge this with the issue description part above to
> prevent confusion.

OK

> > 	  deep sleep on SoC LS1021A
> >
> > Signed-off-by: Biwen Li <biwen.li@....com>
> > Signed-off-by: Ran Wang <ran.wang_1@....com>
> > ---
> >  drivers/soc/fsl/rcpm.c | 42
> > +++++++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 41 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/soc/fsl/rcpm.c b/drivers/soc/fsl/rcpm.c index
> > a093dbe..e6354f5 100644
> > --- a/drivers/soc/fsl/rcpm.c
> > +++ b/drivers/soc/fsl/rcpm.c
> > @@ -2,7 +2,7 @@
> >  //
> >  // rcpm.c - Freescale QorIQ RCPM driver  // -// Copyright 2019 NXP
> > +// Copyright 2019-2020 NXP
> >  //
> >  // Author: Ran Wang <ran.wang_1@....com>
> >
> > @@ -13,6 +13,9 @@
> >  #include <linux/slab.h>
> >  #include <linux/suspend.h>
> >  #include <linux/kernel.h>
> > +#include <linux/acpi.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/regmap.h>
> >
> >  #define RCPM_WAKEUP_CELL_MAX_SIZE	7
> >
> > @@ -37,6 +40,9 @@ static int rcpm_pm_prepare(struct device *dev)
> >  	struct device_node	*np = dev->of_node;
> >  	u32 value[RCPM_WAKEUP_CELL_MAX_SIZE + 1];
> >  	u32 setting[RCPM_WAKEUP_CELL_MAX_SIZE] = {0};
> > +	struct regmap *scfg_addr_regmap = NULL;
> > +	u32 reg_offset[2];
> > +	u32 reg_value = 0;
> >
> >  	rcpm = dev_get_drvdata(dev);
> >  	if (!rcpm)
> > @@ -90,6 +96,40 @@ static int rcpm_pm_prepare(struct device *dev)
> >  			tmp |= ioread32be(address);
> >  			iowrite32be(tmp, address);
> >  		}
> > +		/*
> > +		 * Workaround of errata A-008646 on SoC LS1021A:
> > +		 * There is a bug of register ippdexpcr1.
> > +		 * Reading configuration register RCPM_IPPDEXPCR1
> > +		 * always return zero. So save ippdexpcr1's value
> > +		 * to register SCFG_SPARECR8.And the value of
> > +		 * ippdexpcr1 will be read from SCFG_SPARECR8.
> > +		 */
> > +		if (device_property_present(dev, "fsl,ippdexpcr1-alt-addr"))
> > {
> > +			if (dev_of_node(dev)) {
> > +				scfg_addr_regmap =
> > syscon_regmap_lookup_by_phandle(np,
> > +
> > 	   "fsl,ippdexpcr1-alt-addr");
> > +			} else if (is_acpi_node(dev->fwnode)) {
> > +				continue;
> > +			}
> > +
> > +			if (scfg_addr_regmap && (i == 1)) {
> > +				if (device_property_read_u32_array(dev,
> > +				    "fsl,ippdexpcr1-alt-addr",
> > +				    reg_offset,
> > +				    2)) {
> 
> It is not necessary to read out the whole fsl,ippdexpcr1-alt-addr property if we
> only need the offset.  Also you can change to use the
> syscon_regmap_lookup_by_phandle_args() API above to simplify the code.

Got it, will update it in next version, thanks.

Regards,
Ran

> > +					scfg_addr_regmap = NULL;
> > +					continue;
> > +				}
> > +				/* Read value from register SCFG_SPARECR8
> > */
> > +				regmap_read(scfg_addr_regmap,
> > +					    reg_offset[1],
> > +					    &reg_value);
> > +				/* Write value to register SCFG_SPARECR8 */
> > +				regmap_write(scfg_addr_regmap,
> > +					     reg_offset[1],
> > +					     tmp | reg_value);
> > +			}
> > +		}
> >  	}
> >
> >  	return 0;
> > --
> > 2.7.4