[v3,1/3] soc: fsl: handle RCPM errata A-008646 on SoC LS1021A

[Biwen Li]

Hi all,
the linux patches depended by RCPM driver,FlexTimer driver and FlexTimer dts, need apply these patches as follows:

1. RCPM driver:

https://patchwork.kernel.org/series/162731/mbox/(https://patchwork.kernel.org/patch/11105279/)

2. FlexTimer dts:

https://lore.kernel.org/patchwork/series/405653/mbox/(https://lore.kernel.org/patchwork/patch/1112493/)

3. FlexTimer driver:

https://patchwork.ozlabs.org/series/124718/mbox/(https://patchwork.ozlabs.org/patch/1145999/)

https://patchwork.ozlabs.org/series/126942/mbox/(https://patchwork.ozlabs.org/patch/1152085/)

4. Adjust drivers/soc/fsl/Makefile:

remove the line 'obj-y += ftm_alarm.o' in drivers/soc/fsl/Makefile to resolve a compilation error

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________________________________
From: Biwen Li <biwen.li at nxp.com>
Sent: Tuesday, September 24, 2019 10:45:46 AM
To: Leo Li <leoyang.li at nxp.com>; shawnguo at kernel.org <shawnguo at kernel.org>; robh+dt at kernel.org <robh+dt at kernel.org>; mark.rutland at arm.com <mark.rutland at arm.com>; Ran Wang <ran.wang_1 at nxp.com>
Cc: linuxppc-dev at lists.ozlabs.org <linuxppc-dev at lists.ozlabs.org>; linux-arm-kernel at lists.infradead.org <linux-arm-kernel at lists.infradead.org>; linux-kernel at vger.kernel.org <linux-kernel at vger.kernel.org>; devicetree at vger.kernel.org <devicetree at vger.kernel.org>; Biwen Li <biwen.li at nxp.com>
Subject: [v3,1/3] soc: fsl: handle RCPM errata A-008646 on SoC LS1021A

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
          deep sleep on SoC LS1021A

Signed-off-by: Biwen Li <biwen.li at nxp.com>
---
Change in v3:
        - update commit message
        - rename property name
          fsl,rcpm-scfg -> fsl,ippdexpcr-alt-addr

Change in v2:
        - fix stype problems

 drivers/soc/fsl/rcpm.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/soc/fsl/rcpm.c b/drivers/soc/fsl/rcpm.c
index 82c0ad5e663e..7f42b17d3f29 100644
--- a/drivers/soc/fsl/rcpm.c
+++ b/drivers/soc/fsl/rcpm.c
@@ -13,6 +13,8 @@
 #include <linux/slab.h>
 #include <linux/suspend.h>
 #include <linux/kernel.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>

 #define RCPM_WAKEUP_CELL_MAX_SIZE       7

@@ -29,6 +31,9 @@ static int rcpm_pm_prepare(struct device *dev)
         struct rcpm             *rcpm;
         u32 value[RCPM_WAKEUP_CELL_MAX_SIZE + 1], tmp;
         int i, ret, idx;
+       struct regmap * scfg_addr_regmap = NULL;
+       u32 reg_offset[RCPM_WAKEUP_CELL_MAX_SIZE + 1];
+       u32 reg_value = 0;

         rcpm = dev_get_drvdata(dev);
         if (!rcpm)
@@ -63,6 +68,22 @@ static int rcpm_pm_prepare(struct device *dev)
                                         tmp |= value[i + 1];
                                         iowrite32be(tmp, rcpm->ippdexpcr_base + i * 4);
                                 }
+                               /* 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.
+                                */
+                               scfg_addr_regmap = syscon_regmap_lookup_by_phandle(np, "fsl,ippdexpcr-alt-addr");
+                               if (scfg_addr_regmap) {
+                                       if (of_property_read_u32_array(dev->of_node,
+                                           "fsl,ippdexpcr-alt-addr", reg_offset, rcpm->wakeup_cells + 1)) {
+                                               scfg_addr_regmap = NULL;
+                                               continue;
+                                       }
+                                       regmap_read(scfg_addr_regmap, reg_offset[i + 1], &reg_value);
+                                       /* Write value to register SCFG_SPARECR8 */
+                                       regmap_write(scfg_addr_regmap, reg_offset[i + 1], tmp | reg_value);
+                               }
                         }
                 }
         } while (ws = wakeup_source_get_next(ws));
--
2.17.1

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