[v4,1/3] soc: fsl: handle RCPM errata A-008646 on SoC LS1021A

From: Biwen Li
Date: Wed Sep 25 2019 - 22:52:50 EST


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@xxxxxxx>
---
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 | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)

diff --git a/drivers/soc/fsl/rcpm.c b/drivers/soc/fsl/rcpm.c
index 82c0ad5e663e..9a29c482fc2e 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 +68,34 @@ 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,ippdexpcr1-alt-addr");
+ if (scfg_addr_regmap && (1 == i)) {
+ if (of_property_read_u32_array(dev->of_node,
+ "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);
+ }
}
}
} while (ws = wakeup_source_get_next(ws));
--
2.17.1