lib/regscript: Add exclusive-or (xor) support

Add xor support which enables toggling of a bit:
* REG_SCRIPT_COMMAND_RXW enum value
* REG_*_RXW* macros to support using REG_SCRIPT_COMMAND_RXW
* REG_*_XOR* macros to support using REG_SCRIPT_COMMAND_RXW
* reg_script_rxw routine to perform and/xor operation
* case in reg_script_run_step to call reg_script_rxw

TEST=Build and run on Galileo Gen2

Change-Id: I50a492c7c2643df5dc2d2fa7113e3722c1e480c7
Signed-off-by: Lee Leahy <leroy.p.leahy@intel.com>
Reviewed-on: https://review.coreboot.org/14495
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

2 files changed, 95 insertions, 0 deletions

diff --git a/src/include/reg_script.h b/src/include/reg_script.h
index 60b1188b6c..741641a42c 100644
--- a/src/include/reg_script.h
+++ b/src/include/reg_script.h
@@ -43,6 +43,7 @@ enum {
 	REG_SCRIPT_COMMAND_READ,
 	REG_SCRIPT_COMMAND_WRITE,
 	REG_SCRIPT_COMMAND_RMW,
+	REG_SCRIPT_COMMAND_RXW,
 	REG_SCRIPT_COMMAND_POLL,
 	REG_SCRIPT_COMMAND_SET_DEV,
 	REG_SCRIPT_COMMAND_NEXT,
@@ -156,6 +157,12 @@ const struct reg_script_bus_entry *platform_bus_table(size_t *table_entries);
 	REG_SCRIPT_PCI(RMW, 16, reg_, mask_, value_, 0)
 #define REG_PCI_RMW32(reg_, mask_, value_) \
 	REG_SCRIPT_PCI(RMW, 32, reg_, mask_, value_, 0)
+#define REG_PCI_RXW8(reg_, mask_, value_) \
+	REG_SCRIPT_PCI(RXW, 8, reg_, mask_, value_, 0)
+#define REG_PCI_RXW16(reg_, mask_, value_) \
+	REG_SCRIPT_PCI(RXW, 16, reg_, mask_, value_, 0)
+#define REG_PCI_RXW32(reg_, mask_, value_) \
+	REG_SCRIPT_PCI(RXW, 32, reg_, mask_, value_, 0)
 #define REG_PCI_OR8(reg_, value_) \
 	REG_SCRIPT_PCI(RMW, 8, reg_, 0xff, value_, 0)
 #define REG_PCI_OR16(reg_, value_) \
@@ -168,6 +175,12 @@ const struct reg_script_bus_entry *platform_bus_table(size_t *table_entries);
 	REG_SCRIPT_PCI(POLL, 16, reg_, mask_, value_, timeout_)
 #define REG_PCI_POLL32(reg_, mask_, value_, timeout_) \
 	REG_SCRIPT_PCI(POLL, 32, reg_, mask_, value_, timeout_)
+#define REG_PCI_XOR8(reg_, value_) \
+	REG_SCRIPT_PCI(RXW, 8, reg_, 0xff, value_, 0)
+#define REG_PCI_XOR16(reg_, value_) \
+	REG_SCRIPT_PCI(RXW, 16, reg_, 0xffff, value_, 0)
+#define REG_PCI_XOR32(reg_, value_) \
+	REG_SCRIPT_PCI(RXW, 32, reg_, 0xffffffff, value_, 0)
 
 /*
  * Legacy IO
@@ -196,6 +209,12 @@ const struct reg_script_bus_entry *platform_bus_table(size_t *table_entries);
 	REG_SCRIPT_IO(RMW, 16, reg_, mask_, value_, 0)
 #define REG_IO_RMW32(reg_, mask_, value_) \
 	REG_SCRIPT_IO(RMW, 32, reg_, mask_, value_, 0)
+#define REG_IO_RXW8(reg_, mask_, value_) \
+	REG_SCRIPT_IO(RXW, 8, reg_, mask_, value_, 0)
+#define REG_IO_RXW16(reg_, mask_, value_) \
+	REG_SCRIPT_IO(RXW, 16, reg_, mask_, value_, 0)
+#define REG_IO_RXW32(reg_, mask_, value_) \
+	REG_SCRIPT_IO(RXW, 32, reg_, mask_, value_, 0)
 #define REG_IO_OR8(reg_, value_) \
 	REG_IO_RMW8(reg_, 0xff, value_)
 #define REG_IO_OR16(reg_, value_) \
@@ -208,6 +227,12 @@ const struct reg_script_bus_entry *platform_bus_table(size_t *table_entries);
 	REG_SCRIPT_IO(POLL, 16, reg_, mask_, value_, timeout_)
 #define REG_IO_POLL32(reg_, mask_, value_, timeout_) \
 	REG_SCRIPT_IO(POLL, 32, reg_, mask_, value_, timeout_)
+#define REG_IO_XOR8(reg_, value_) \
+	REG_IO_RXW8(reg_, 0xff, value_)
+#define REG_IO_XOR16(reg_, value_) \
+	REG_IO_RXW16(reg_, 0xffff, value_)
+#define REG_IO_XOR32(reg_, value_) \
+	REG_IO_RXW32(reg_, 0xffffffff, value_)
 
 /*
  * Memory Mapped IO
@@ -236,6 +261,12 @@ const struct reg_script_bus_entry *platform_bus_table(size_t *table_entries);
 	REG_SCRIPT_MMIO(RMW, 16, reg_, mask_, value_, 0)
 #define REG_MMIO_RMW32(reg_, mask_, value_) \
 	REG_SCRIPT_MMIO(RMW, 32, reg_, mask_, value_, 0)
+#define REG_MMIO_RXW8(reg_, mask_, value_) \
+	REG_SCRIPT_MMIO(RXW, 8, reg_, mask_, value_, 0)
+#define REG_MMIO_RXW16(reg_, mask_, value_) \
+	REG_SCRIPT_MMIO(RXW, 16, reg_, mask_, value_, 0)
+#define REG_MMIO_RXW32(reg_, mask_, value_) \
+	REG_SCRIPT_MMIO(RXW, 32, reg_, mask_, value_, 0)
 #define REG_MMIO_OR8(reg_, value_) \
 	REG_MMIO_RMW8(reg_, 0xff, value_)
 #define REG_MMIO_OR16(reg_, value_) \
@@ -248,6 +279,12 @@ const struct reg_script_bus_entry *platform_bus_table(size_t *table_entries);
 	REG_SCRIPT_MMIO(POLL, 16, reg_, mask_, value_, timeout_)
 #define REG_MMIO_POLL32(reg_, mask_, value_, timeout_) \
 	REG_SCRIPT_MMIO(POLL, 32, reg_, mask_, value_, timeout_)
+#define REG_MMIO_XOR8(reg_, value_) \
+	REG_MMIO_RXW8(reg_, 0xff, value_)
+#define REG_MMIO_XOR16(reg_, value_) \
+	REG_MMIO_RXW16(reg_, 0xffff, value_)
+#define REG_MMIO_XOR32(reg_, value_) \
+	REG_MMIO_RXW32(reg_, 0xffffffff, value_)
 
 /*
  * Access through a device's resource such as a Base Address Register (BAR)
@@ -276,6 +313,12 @@ const struct reg_script_bus_entry *platform_bus_table(size_t *table_entries);
 	REG_SCRIPT_RES(RMW, 16, bar_, reg_, mask_, value_, 0)
 #define REG_RES_RMW32(bar_, reg_, mask_, value_) \
 	REG_SCRIPT_RES(RMW, 32, bar_, reg_, mask_, value_, 0)
+#define REG_RES_RXW8(bar_, reg_, mask_, value_) \
+	REG_SCRIPT_RES(RXW, 8, bar_, reg_, mask_, value_, 0)
+#define REG_RES_RXW16(bar_, reg_, mask_, value_) \
+	REG_SCRIPT_RES(RXW, 16, bar_, reg_, mask_, value_, 0)
+#define REG_RES_RXW32(bar_, reg_, mask_, value_) \
+	REG_SCRIPT_RES(RXW, 32, bar_, reg_, mask_, value_, 0)
 #define REG_RES_OR8(bar_, reg_, value_) \
 	REG_RES_RMW8(bar_, reg_, 0xff, value_)
 #define REG_RES_OR16(bar_, reg_, value_) \
@@ -288,6 +331,12 @@ const struct reg_script_bus_entry *platform_bus_table(size_t *table_entries);
 	REG_SCRIPT_RES(POLL, 16, bar_, reg_, mask_, value_, timeout_)
 #define REG_RES_POLL32(bar_, reg_, mask_, value_, timeout_) \
 	REG_SCRIPT_RES(POLL, 32, bar_, reg_, mask_, value_, timeout_)
+#define REG_RES_XOR8(bar_, reg_, value_) \
+	REG_RES_RXW8(bar_, reg_, 0xff, value_)
+#define REG_RES_XOR16(bar_, reg_, value_) \
+	REG_RES_RXW16(bar_, reg_, 0xffff, value_)
+#define REG_RES_XOR32(bar_, reg_, value_) \
+	REG_RES_RXW32(bar_, reg_, 0xffffffff, value_)
 
 
 #if IS_ENABLED(CONFIG_SOC_INTEL_BAYTRAIL) || \
@@ -307,10 +356,14 @@ IS_ENABLED(CONFIG_SOC_INTEL_FSP_BAYTRAIL)
 	REG_SCRIPT_IOSF(WRITE, unit_, reg_, 0, value_, 0)
 #define REG_IOSF_RMW(unit_, reg_, mask_, value_) \
 	REG_SCRIPT_IOSF(RMW, unit_, reg_, mask_, value_, 0)
+#define REG_IOSF_RXW(unit_, reg_, mask_, value_) \
+	REG_SCRIPT_IOSF(RXW, unit_, reg_, mask_, value_, 0)
 #define REG_IOSF_OR(unit_, reg_, value_) \
 	REG_IOSF_RMW(unit_, reg_, 0xffffffff, value_)
 #define REG_IOSF_POLL(unit_, reg_, mask_, value_, timeout_) \
 	REG_SCRIPT_IOSF(POLL, unit_, reg_, mask_, value_, timeout_)
+#define REG_IOSF_XOR(unit_, reg_, value_) \
+	REG_IOSF_RXW(unit_, reg_, 0xffffffff, value_)
 #endif	/* CONFIG_SOC_INTEL_BAYTRAIL || CONFIG_SOC_INTEL_FSP_BAYTRAIL*/
 
 /*
@@ -328,10 +381,14 @@ IS_ENABLED(CONFIG_SOC_INTEL_FSP_BAYTRAIL)
 	REG_SCRIPT_MSR(WRITE, reg_, 0, value_, 0)
 #define REG_MSR_RMW(reg_, mask_, value_) \
 	REG_SCRIPT_MSR(RMW, reg_, mask_, value_, 0)
+#define REG_MSR_RXW(reg_, mask_, value_) \
+	REG_SCRIPT_MSR(RXW, reg_, mask_, value_, 0)
 #define REG_MSR_OR(reg_, value_) \
 	REG_MSR_RMW(reg_, -1ULL, value_)
 #define REG_MSR_POLL(reg_, mask_, value_, timeout_) \
 	REG_SCRIPT_MSR(POLL, reg_, mask_, value_, timeout_)
+#define REG_MSR_XOR(reg_, value_) \
+	REG_MSR_RXW(reg_, -1ULL, value_)
 
 /*
  * Chain to another table.
diff --git a/src/lib/reg_script.c b/src/lib/reg_script.c
index 7f8200006e..7530dc32b8 100644
--- a/src/lib/reg_script.c
+++ b/src/lib/reg_script.c
@@ -521,6 +521,41 @@ static void reg_script_rmw(struct reg_script_context *ctx)
 	reg_script_set_step(ctx, step);
 }
 
+static void reg_script_rxw(struct reg_script_context *ctx)
+{
+	uint64_t value;
+	const struct reg_script *step = reg_script_get_step(ctx);
+	struct reg_script write_step = *step;
+
+/*
+ * XOR logic table
+ *      Input  XOR  Value
+ *        0     0     0
+ *        0     1     1
+ *        1     0     1
+ *        1     1     0
+ *
+ * Supported operations
+ *
+ *      Input  Mask  Temp  XOR  Value  Operation
+ *        0      0    0     0     0    Clear bit
+ *        1      0    0     0     0
+ *        0      0    0     1     1    Set bit
+ *        1      0    0     1     1
+ *        0      1    0     0     0    Preserve bit
+ *        1      1    1     0     1
+ *        0      1    0     1     1    Toggle bit
+ *        1      1    1     1     0
+ */
+	value = reg_script_read(ctx);
+	value &= step->mask;
+	value ^= step->value;
+	write_step.value = value;
+	reg_script_set_step(ctx, &write_step);
+	reg_script_write(ctx);
+	reg_script_set_step(ctx, step);
+}
+
 /* In order to easily chain scripts together handle the REG_SCRIPT_COMMAND_NEXT
  * as recursive call with a new context that has the same dev and resource
  * as the previous one. That will run to completion and then move on to the
@@ -544,6 +579,9 @@ static void reg_script_run_step(struct reg_script_context *ctx,
 	case REG_SCRIPT_COMMAND_RMW:
 		reg_script_rmw(ctx);
 		break;
+	case REG_SCRIPT_COMMAND_RXW:
+		reg_script_rxw(ctx);
+		break;
 	case REG_SCRIPT_COMMAND_POLL:
 		for (try = 0; try < step->timeout; try += POLL_DELAY) {
 			value = reg_script_read(ctx) & step->mask;