New patch to review for coreboot: 381a896 libpayload arm64: Initialize and enable MMU

[Patrick Georgi]

Patrick Georgi ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/8792

-gerrit

commit 381a8961c21611788b867b801e59ad29e4482d3f
Author: Furquan Shaikh 
Date:   Thu Sep 4 15:33:00 2014 -0700

libpayload arm64: Initialize and enable MMU

What this change does:
    1) Initialize limited page tables as soon as we jump into libpayload. Basically
    two ranges are initialized. One is for the BASE_ADDRESS and other is for the
    coreboot_tables. With page tables initialized and MMU enabled, we jump into
    code to parse coreboot tables.
    2) Once coreboot tables are parsed and we have complete picture of the memory,
    we perform a complete page table initialzation and enable MMU and then jump to
    payload.

Additionally, we also:
    1) Initialize DMA memory on our own depending upon the memory map. It ensures
    that the DMA buffer is placed in 32-bit memory.

CQ-DEPEND=CL:216826
    BUG=chrome-os-partner:31634
    BRANCH=None
    TEST=Compiles successfully and we are able to start execution of libpayload in
    EL2 and reach kernel login prompt

Change-Id: I8a6203e465868bc2a3e5cc377e108f36cc58e2fa
    Signed-off-by: Patrick Georgi 
    Original-Commit-Id: 7695bb7afe34ea460282125a0be440e8994b01e4
    Original-Change-Id: Ie0f47b7759d4ac65a6920f7f2f7502b889afda6d
    Original-Signed-off-by: Furquan Shaikh 
    Original-Reviewed-on: https://chromium-review.googlesource.com/216824
    Original-Reviewed-by: Aaron Durbin 
    Original-Tested-by: Furquan Shaikh 
    Original-Commit-Queue: Furquan Shaikh 
---
 payloads/libpayload/arch/arm64/main.c | 64 +++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/payloads/libpayload/arch/arm64/main.c b/payloads/libpayload/arch/arm64/main.c
index 6b45a01..4561e2e 100644
--- a/payloads/libpayload/arch/arm64/main.c
+++ b/payloads/libpayload/arch/arm64/main.c
@@ -29,6 +29,7 @@

#include <exception.h>
 #include <libpayload.h>
+#include <arch/mmu.h>

unsigned int main_argc;    /**< The argc value to pass to main() */

@@ -48,6 +49,64 @@ static int test_exception(void)
    return 0;
 }

+/*
+ * Func: pre_sysinfo_scan_mmu_setup
+ * Desc: We need to setup and enable MMU before we can go to scan coreboot
+ * tables. However, we are not sure what all memory regions to map. Thus,
+ * initializing minimum required memory ranges
+ */
+static void pre_sysinfo_scan_mmu_setup(void)
+{
+	uint64_t start = (uint64_t)&_start;
+	uint64_t end = (uint64_t)&_end;
+
+	/* Memory range 1: Covers the area occupied by payload */
+	mmu_presysinfo_memory_used(start, end - start);
+
+	/*
+	 * Memory range 2: Coreboot tables
+	 *
+	 * Maximum size is assumed 2 pages in case it crosses the GRANULE_SIZE
+	 * boundary
+	 */
+	mmu_presysinfo_memory_used((uint64_t)get_cb_header_ptr(),
+				   2 * GRANULE_SIZE);
+
+	mmu_presysinfo_enable();
+}
+
+/*
+ * Func: post_sysinfo_scan_mmu_setup
+ * Desc: Once we have scanned coreboot tables, we have complete information
+ * about different memory ranges. Thus, we can perform a complete mmu
+ * initialization. Also, this takes care of DMA area setup
+ */
+static void post_sysinfo_scan_mmu_setup(void)
+{
+	struct memrange *ranges;
+	uint64_t nranges;
+	struct mmu_ranges mmu_ranges;
+	struct mmu_memrange *dma_range;
+
+	/* Get memrange info from lib_sysinfo */
+	lib_sysinfo_get_memranges(&ranges, &nranges);
+
+	/* Get memory ranges for mmu init from lib_sysinfo memrange */
+	dma_range = mmu_init_ranges_from_sysinfo(ranges, nranges, &mmu_ranges);
+
+	/* Disable mmu */
+	mmu_disable();
+
+	/* Init mmu */
+	mmu_init(&mmu_ranges);
+
+	/* Enable mmu */
+	mmu_enable();
+
+	/* Init dma memory */
+	init_dma_memory((void *)dma_range->base, dma_range->size);
+}
+
 /**
  * This is our C entry function - set up the system
  * and jump into the payload entry point.
@@ -57,12 +116,17 @@ void start_main(void)
 {
    extern int main(int argc, char **argv);

+	pre_sysinfo_scan_mmu_setup();
+
    /* Gather system information. */
    lib_get_sysinfo();

#ifndef CONFIG_LP_SKIP_CONSOLE_INIT
    console_init();
 #endif
+
+	post_sysinfo_scan_mmu_setup();
+
    printf("ARM64: Libpayload %s\n",__func__);
    exception_init();