[coreboot-gerrit] Change in coreboot[master]: emulation/qemu-i440fx: use fw_cfg_dma for fw_cfg_read

[Name of user not set (Code Review)]

Name of user not set #1002476 has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/35365 )

Change subject: emulation/qemu-i440fx: use fw_cfg_dma for fw_cfg_read
......................................................................

emulation/qemu-i440fx: use fw_cfg_dma for fw_cfg_read

- configure DMA fw_cfg
- add support to read using fw_cfg_dma
- provide fw config version id info in logs

Change-Id: I0be5355b124af40aba62c0840790d46ed0fe80a2
Signed-off-by: Himanshu Sahdev 
---
M src/mainboard/emulation/qemu-i440fx/fw_cfg.c
M src/mainboard/emulation/qemu-i440fx/fw_cfg_if.h
2 files changed, 69 insertions(+), 3 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/65/35365/1

diff --git a/src/mainboard/emulation/qemu-i440fx/fw_cfg.c b/src/mainboard/emulation/qemu-i440fx/fw_cfg.c
index 3acb11e..330c6c0 100644
--- a/src/mainboard/emulation/qemu-i440fx/fw_cfg.c
+++ b/src/mainboard/emulation/qemu-i440fx/fw_cfg.c
@@ -24,13 +24,18 @@

#define FW_CFG_PORT_CTL       0x0510
 #define FW_CFG_PORT_DATA      0x0511
+#define FW_CFG_DMA_ADDR_HIGH  0x0514
+#define FW_CFG_DMA_ADDR_LOW   0x0518

static int fw_cfg_detected;
+static uint8_t fw_ver;
+
+static void fw_cfg_dma(int control, void *buf, int len);

static int fw_cfg_present(void)
 {
    static const char qsig[] = "QEMU";
-	unsigned char sig[4];
+	unsigned char sig[FW_CFG_SIG_SIZE];
    int detected = 0;

if (fw_cfg_detected == 0) {
@@ -38,6 +43,10 @@
    	detected = memcmp(sig, qsig, 4) == 0;
    	printk(BIOS_INFO, "QEMU: firmware config interface %s\n",
    			detected ? "detected" : "not found");
+		if (detected) {
+			fw_cfg_get(FW_CFG_ID, &fw_ver, sizeof(fw_ver));
+			printk(BIOS_INFO, "Firmware config version id: %d\n", fw_ver);
+		}
    	fw_cfg_detected = detected + 1;
    }
    return fw_cfg_detected - 1;
@@ -50,7 +59,10 @@

static void fw_cfg_read(void *dst, int dstlen)
 {
-	insb(FW_CFG_PORT_DATA, dst, dstlen);
+	if (fw_ver & FW_CFG_VERSION_DMA)
+		fw_cfg_dma(FW_CFG_DMA_CTL_READ, dst, dstlen);
+	else
+		insb(FW_CFG_PORT_DATA, dst, dstlen);
 }

void fw_cfg_get(uint16_t entry, void *dst, int dstlen)
@@ -500,3 +512,22 @@
    fw_cfg_smbios_init();
    memcpy(uuid, type1_uuid, 16);
 }
+
+/*
+ * Configure DMA setup
+ */
+
+static void fw_cfg_dma(int control, void *buf, int len)
+{
+	volatile FwCfgDmaAccess dma;
+	uint32_t dma_desc_addr;
+
+	dma.control = be32_to_cpu(control);
+	dma.length  = be32_to_cpu(len);
+	dma.address = be64_to_cpu((uintptr_t)buf);
+
+	dma_desc_addr = (uint32_t)&dma;
+	outl(be32_to_cpu(dma_desc_addr), FW_CFG_DMA_ADDR_LOW);
+	while (be32_to_cpu(dma.control) & ~FW_CFG_DMA_CTL_ERROR)
+		asm("");
+}
diff --git a/src/mainboard/emulation/qemu-i440fx/fw_cfg_if.h b/src/mainboard/emulation/qemu-i440fx/fw_cfg_if.h
index 46aee9b3d..3590943 100644
--- a/src/mainboard/emulation/qemu-i440fx/fw_cfg_if.h
+++ b/src/mainboard/emulation/qemu-i440fx/fw_cfg_if.h
@@ -64,11 +64,24 @@

#define FW_CFG_INVALID          0xffff

+/* width in bytes of fw_cfg control register */
+#define FW_CFG_CTL_SIZE         0x02
+
+/* fw_cfg "file name" is up to 56 characters (including terminating nul) */
+#define FW_CFG_MAX_FILE_PATH    56
+
+/* size in bytes of fw_cfg signature */
+#define FW_CFG_SIG_SIZE 4
+
+/* FW_CFG_ID bits */
+#define FW_CFG_VERSION          0x01
+#define FW_CFG_VERSION_DMA      0x02
+
 typedef struct FWCfgFile {
     uint32_t  size;        /* file size */
     uint16_t  select;      /* write this to 0x510 to read it */
     uint16_t  reserved;
-    char      name[56];
+    char      name[FW_CFG_MAX_FILE_PATH];
 } FWCfgFile;

typedef struct FWCfgFiles {
@@ -93,4 +106,26 @@
    uint16_t fieldoffset;
 } FwCfgSmbios;

+/* FW_CFG_ID bits */
+#define FW_CFG_VERSION          0x01
+#define FW_CFG_VERSION_DMA      0x02
+
+/* FW_CFG_DMA_CONTROL bits */
+#define FW_CFG_DMA_CTL_ERROR    0x01
+#define FW_CFG_DMA_CTL_READ     0x02
+#define FW_CFG_DMA_CTL_SKIP     0x04
+#define FW_CFG_DMA_CTL_SELECT   0x08
+#define FW_CFG_DMA_CTL_WRITE    0x10
+
+#define FW_CFG_DMA_SIGNATURE    0x51454d5520434647ULL /* "QEMU CFG" */
+
+/* Control as first field allows for different structures selected by this
+ * field, which might be useful in the future
+ */
+typedef struct FwCfgDmaAccess {
+	uint32_t control;
+	uint32_t length;
+	uint64_t address;
+} FwCfgDmaAccess;
+
 #endif /* FW_CFG_IF_H */