Patch set updated for coreboot: [WIP] arch/riscv: Make SBI support optional

[Jonathan Neuschäfer]

Jonathan Neuschäfer ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/15510

-gerrit

commit 6417d8d426d976730fa03b502dcfa431d837e9d9
Author: Jonathan Neuschäfer <[e-mail]>
Date:   Thu Jun 30 22:58:53 2016 +0200

    [WIP] arch/riscv: Make SBI support optional
    
    I'm posting this patch early so I can link to it from the wiki.
    
    Change-Id: I5cbfc90afd3febab33835935f08005136a3f47e9
    Signed-off-by: Jonathan Neuschäfer <[e-mail]>
---
 payloads/Kconfig                | 12 ++++++++++++
 src/arch/riscv/boot.c           |  4 ++++
 src/arch/riscv/virtual_memory.c |  1 +
 3 files changed, 17 insertions(+)

diff --git a/payloads/Kconfig b/payloads/Kconfig
index 8cce778..69d2e41 100644
--- a/payloads/Kconfig
+++ b/payloads/Kconfig
@@ -47,6 +47,18 @@ config COMPRESSED_PAYLOAD_LZMA
 	  In order to reduce the size payloads take up in the ROM chip
 	  coreboot can compress them using the LZMA algorithm.
 
+config PAYLOAD_RISCV_SMODE
+	bool "Run payload in S-mode and provide SBI"
+	depends on ARCH_RISCV
+	default y
+	help
+	  If Y is selected, coreboot will start the payload in supervisor mode
+	  (S-mode) and provide a an implementation of the System Binary
+	  Interface (SBI).
+
+	  Otherwise, the payload will be run in M-mode and will have to provide
+	  its own SBI implementation, if it needs one.
+
 config PAYLOAD_OPTIONS
 	string
 	default ""
diff --git a/src/arch/riscv/boot.c b/src/arch/riscv/boot.c
index 96526bf..5830ac4 100644
--- a/src/arch/riscv/boot.c
+++ b/src/arch/riscv/boot.c
@@ -22,6 +22,7 @@ void arch_prog_run(struct prog *prog)
 {
 	void (*doit)(void *) = prog_entry(prog);
 
+#if IS_ENABLED(CONFIG_PAYLOAD_RISCV_SMODE)
 	if (ENV_RAMSTAGE && prog_type(prog) == PROG_PAYLOAD) {
 		initVirtualMemory();
 		write_csr(mepc, doit);
@@ -29,6 +30,9 @@ void arch_prog_run(struct prog *prog)
 	} else {
 		doit(prog_entry_arg(prog));
 	}
+#else
+	doit(prog_entry_arg(prog));
+#endif
 }
 
 int arch_supports_bounce_buffer(void)
diff --git a/src/arch/riscv/virtual_memory.c b/src/arch/riscv/virtual_memory.c
index 64ea2b1..dce0887 100644
--- a/src/arch/riscv/virtual_memory.c
+++ b/src/arch/riscv/virtual_memory.c
@@ -101,6 +101,7 @@ void init_vm(uintptr_t virtMemStart, uintptr_t physMemStart, uintptr_t pageTable
 
 void initVirtualMemory(void) {
 	printk(BIOS_DEBUG, "Initializing virtual memory...\n");
+	return;
 	uintptr_t physicalStart = 0x1000000; // TODO: Figure out how to grab this from cbfs
 	uintptr_t virtualStart = 0xffffffff81000000;
 	uintptr_t pageTableStart = 0x1400000;