From 508a27204cbbca0a9430236e56681e5e0d343fb9 Mon Sep 17 00:00:00 2001
From: Alistair Francis <alistair.francis@wdc.com>
Date: Fri, 8 Mar 2019 11:22:22 -0800
Subject: [PATCH] lib: Create a sbi_ipi_data structure

Create a sbi_ipi_data structure that holds unpacked IPI information. At
the same time remove ipi_type from the sbi_scratch struct and use a
fixed offset to access it.

This structure fits in behind the sbi_scratch structure.

This fixes https://github.com/riscv/opensbi/issues/81

Upstream-Status: Backport [https://github.com/riscv/opensbi/commit/508a27204cbbca0a9430236e56681e5e0d343fb9]
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 firmware/fw_base.S        |  1 -
 include/sbi/sbi_scratch.h | 23 ++++++++++++++++-------
 lib/sbi_ipi.c             |  8 +++++---
 3 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/firmware/fw_base.S b/firmware/fw_base.S
index cf2c6a0..69cfc90 100644
--- a/firmware/fw_base.S
+++ b/firmware/fw_base.S
@@ -183,7 +183,6 @@ _start_warm:
 	REG_S	a4, SBI_SCRATCH_PLATFORM_ADDR_OFFSET(tp)
 	la	a4, _hartid_to_scratch
 	REG_S	a4, SBI_SCRATCH_HARTID_TO_SCRATCH_OFFSET(tp)
-	REG_S	zero, SBI_SCRATCH_IPI_TYPE_OFFSET(tp)
 	REG_S	zero, SBI_SCRATCH_TMP0_OFFSET(tp)
 
 	/* Setup stack */
diff --git a/include/sbi/sbi_scratch.h b/include/sbi/sbi_scratch.h
index 8389ef3..70ab384 100644
--- a/include/sbi/sbi_scratch.h
+++ b/include/sbi/sbi_scratch.h
@@ -28,17 +28,24 @@
 #define SBI_SCRATCH_PLATFORM_ADDR_OFFSET	(6 * __SIZEOF_POINTER__)
 /** Offset of hartid_to_scratch member in sbi_scratch */
 #define SBI_SCRATCH_HARTID_TO_SCRATCH_OFFSET	(7 * __SIZEOF_POINTER__)
-/** Offset of ipi_type member in sbi_scratch */
-#define SBI_SCRATCH_IPI_TYPE_OFFSET		(8 * __SIZEOF_POINTER__)
 /** Offset of tmp0 member in sbi_scratch */
-#define SBI_SCRATCH_TMP0_OFFSET			(9 * __SIZEOF_POINTER__)
-/** Maximum size of sbi_scratch */
-#define SBI_SCRATCH_SIZE			256
+#define SBI_SCRATCH_TMP0_OFFSET			(8 * __SIZEOF_POINTER__)
+
+/** sbi_ipi_data is located behind sbi_scratch. This struct is not packed. */
+/** Offset of ipi_type in sbi_ipi_data */
+#define SBI_IPI_DATA_IPI_TYPE_OFFSET		(15 * __SIZEOF_POINTER__)
+
+/** Maximum size of sbi_scratch and sbi_ipi_data */
+#define SBI_SCRATCH_SIZE			(32 * __SIZEOF_POINTER__)
 
 #ifndef __ASSEMBLY__
 
 #include <sbi/sbi_types.h>
 
+struct sbi_ipi_data {
+	unsigned long ipi_type;
+};
+
 /** Representation of per-HART scratch space */
 struct sbi_scratch {
 	/** Start (or base) address of firmware linked to OpenSBI library */
@@ -57,8 +64,6 @@ struct sbi_scratch {
 	unsigned long platform_addr;
 	/** Address of HART ID to sbi_scratch conversion function */
 	unsigned long hartid_to_scratch;
-	/** IPI type (or flags) */
-	unsigned long ipi_type;
 	/** Temporary storage */
 	unsigned long tmp0;
 } __packed;
@@ -71,6 +76,10 @@ struct sbi_scratch {
 #define sbi_scratch_thishart_arg1_ptr()	\
 ((void *)(sbi_scratch_thishart_ptr()->next_arg1))
 
+/** Get pointer to sbi_ipi_data from sbi_scratch */
+#define sbi_ipi_data_ptr(scratch)      \
+((struct sbi_ipi_data *)(void*)scratch + SBI_IPI_DATA_IPI_TYPE_OFFSET)
+
 #endif
 
 #endif
diff --git a/lib/sbi_ipi.c b/lib/sbi_ipi.c
index 0e371d7..e0f2a19 100644
--- a/lib/sbi_ipi.c
+++ b/lib/sbi_ipi.c
@@ -31,7 +31,7 @@ static int sbi_ipi_send(struct sbi_scratch *scratch, u32 hartid, u32 event)
 	 * trigger the interrupt
 	 */
 	remote_scratch = sbi_hart_id_to_scratch(scratch, hartid);
-	atomic_raw_set_bit(event, &remote_scratch->ipi_type);
+	atomic_raw_set_bit(event, &sbi_ipi_data_ptr(remote_scratch)->ipi_type);
 	mb();
 	sbi_platform_ipi_send(plat, hartid);
 	if (event != SBI_IPI_EVENT_SOFT)
@@ -80,7 +80,7 @@ void sbi_ipi_process(struct sbi_scratch *scratch)
 	sbi_platform_ipi_clear(plat, hartid);
 
 	do {
-		ipi_type = scratch->ipi_type;
+		ipi_type = sbi_ipi_data_ptr(scratch)->ipi_type;
 		rmb();
 		ipi_event = __ffs(ipi_type);
 		switch (ipi_event) {
@@ -97,12 +97,14 @@ void sbi_ipi_process(struct sbi_scratch *scratch)
 			sbi_hart_hang();
 			break;
 		};
-		ipi_type = atomic_raw_clear_bit(ipi_event, &scratch->ipi_type);
+		ipi_type = atomic_raw_clear_bit(ipi_event, &sbi_ipi_data_ptr(scratch)->ipi_type);
 	} while(ipi_type > 0);
 }
 
 int sbi_ipi_init(struct sbi_scratch *scratch, bool cold_boot)
 {
+	sbi_ipi_data_ptr(scratch)->ipi_type = 0x00;
+
 	/* Enable software interrupts */
 	csr_set(CSR_MIE, MIP_MSIP);
 
-- 
2.22.0