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...@nxp.com>
---
Change in v5:
        - update the patch, because of rcpm driver has updated.

Change in v4:
        - rename property name
          fsl,ippdexpcr-alt-addr -> fsl,ippdexpcr1-alt-addr

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 | 47 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 45 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/fsl/rcpm.c b/drivers/soc/fsl/rcpm.c
index a093dbe6d2cb..775c618f0456 100644
--- a/drivers/soc/fsl/rcpm.c
+++ b/drivers/soc/fsl/rcpm.c
@@ -6,13 +6,16 @@
 //
 // Author: Ran Wang <ran.wan...@nxp.com>
 
+#include <linux/acpi.h>
 #include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
 #include <linux/module.h>
-#include <linux/platform_device.h>
 #include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
 #include <linux/slab.h>
 #include <linux/suspend.h>
-#include <linux/kernel.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[RCPM_WAKEUP_CELL_MAX_SIZE + 1];
+       u32 reg_value = 0;
 
        rcpm = dev_get_drvdata(dev);
        if (!rcpm)
@@ -90,6 +96,43 @@ 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)) {
+                               dev_err(dev, "not support acpi for rcpm\n");
+                               continue;
+                       }
+
+                       if (scfg_addr_regmap && (i == 1)) {
+                               if (device_property_read_u32_array(dev,
+                                   "fsl,ippdexpcr1-alt-addr",
+                                   reg_offset,
+                                   1 + sizeof(u64)/sizeof(u32))) {
+                                       scfg_addr_regmap = NULL;
+                                       continue;
+                               }
+                               /* Read value from register SCFG_SPARECR8 */
+                               regmap_read(scfg_addr_regmap,
+                                           (u32)(((u64)(reg_offset[1] << 
(sizeof(u32) * 8) |
+                                           reg_offset[2])) & 0xffffffff),
+                                           &reg_value);
+                               /* Write value to register SCFG_SPARECR8 */
+                               regmap_write(scfg_addr_regmap,
+                                            (u32)(((u64)(reg_offset[1] << 
(sizeof(u32) * 8) |
+                                            reg_offset[2])) & 0xffffffff),
+                                            tmp | reg_value);
+                       }
+               }
        }
 
        return 0;
-- 
2.17.1

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