mediatek/mt8173: memlayout: Create DRAM DMA region for NOR flash DMA read.

NOR flash has a hardware limitation that it can't access SRAM region
after 4GB mode is enabled. We add a DRAM DMA region after 0x40000000
for NOR flash driver. So that the NOR flash driver can use this region
after 4GB mode is enabled.

BRANCH=none
BUG=chormoe-os-partner:49229
TEST=Boot to kernel on rev4 w/ 2GB ram and rev3 w/ 4GB ram.
     And check /proc/meminfo.

Change-Id: I4a86f0028b26509589ec8d09e2d077920446ece1
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: dc61ec55187959101a9e891fe5e93928e9b8176e
Original-Change-Id: Ifedc9e2dfba5d294297b3a28134997ac1dd38f94
Original-Signed-off-by: Yidi Lin <yidi.lin@mediatek.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/327962
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/331177
Original-Commit-Ready: Patrick Georgi <pgeorgi@chromium.org>
Original-Tested-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: https://review.coreboot.org/13989
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/soc/mediatek/mt8173/flash_controller.c

@@ -26,6 +26,7 @@
 #include <symbols.h>
 #include <timer.h>
 #include <soc/flash_controller.h>
+#include <soc/mmu_operations.h>
 
 #define get_nth_byte(d, n)	((d >> (8 * n)) & 0xff)
 
@@ -112,21 +113,22 @@ unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
 	return min(65535, buf_len);
 }
 
-static int dma_read(u32 addr, u8 *buf, u32 len)
+static int dma_read(u32 addr, u8 *buf, u32 len, uintptr_t dma_buf,
+		    size_t dma_buf_len)
 {
 	struct stopwatch sw;
 
 	assert(IS_ALIGNED((uintptr_t)buf, SFLASH_DMA_ALIGN) &&
 	       IS_ALIGNED(len, SFLASH_DMA_ALIGN) &&
-	       len <= _dma_coherent_size);
+	       len <= dma_buf_len);
 
 	/* do dma reset */
 	write32(&mt8173_nor->fdma_ctl, SFLASH_DMA_SW_RESET);
 	write32(&mt8173_nor->fdma_ctl, SFLASH_DMA_WDLE_EN);
 	/* flash source address and dram dest address */
 	write32(&mt8173_nor->fdma_fadr, addr);
-	write32(&mt8173_nor->fdma_dadr, ((uintptr_t)_dma_coherent ));
-	write32(&mt8173_nor->fdma_end_dadr, ((uintptr_t)_dma_coherent + len));
+	write32(&mt8173_nor->fdma_dadr, dma_buf);
+	write32(&mt8173_nor->fdma_end_dadr, (dma_buf + len));
 	/* start dma */
 	write32(&mt8173_nor->fdma_ctl, SFLASH_DMA_TRIGGER | SFLASH_DMA_WDLE_EN);
 
@@ -138,7 +140,7 @@ static int dma_read(u32 addr, u8 *buf, u32 len)
 		}
 	}
 
-	memcpy(buf, _dma_coherent, len);
+	memcpy(buf, (const void *)dma_buf, len);
 	return 0;
 }
 
@@ -160,6 +162,9 @@ static int nor_read(struct spi_flash *flash, u32 addr, size_t len, void *buf)
 	u32 next;
 
 	size_t done = 0;
+	uintptr_t dma_buf;
+	size_t dma_buf_len;
+
 	if (!IS_ALIGNED((uintptr_t)buf, SFLASH_DMA_ALIGN)) {
 		next = MIN(ALIGN_UP((uintptr_t)buf, SFLASH_DMA_ALIGN) -
 			   (uintptr_t)buf, len);
@@ -167,10 +172,20 @@ static int nor_read(struct spi_flash *flash, u32 addr, size_t len, void *buf)
 			return -1;
 		done += next;
 	}
+
+	if (ENV_BOOTBLOCK || ENV_VERSTAGE) {
+		dma_buf = (uintptr_t)_dma_coherent;
+		dma_buf_len = _dma_coherent_size;
+	} else {
+		dma_buf = (uintptr_t)_dram_dma;
+		dma_buf_len = _dram_dma_size;
+	}
+
 	while (len - done >= SFLASH_DMA_ALIGN) {
-		next = MIN(_dma_coherent_size, ALIGN_DOWN(len - done,
+		next = MIN(dma_buf_len, ALIGN_DOWN(len - done,
 			   SFLASH_DMA_ALIGN));
-		if (dma_read(addr + done, buf + done, next))
+		if (dma_read(addr + done, buf + done, next, dma_buf,
+			     dma_buf_len))
 			return -1;
 		done += next;
 	}

src/soc/mediatek/mt8173/include/soc/memlayout.ld

@@ -25,6 +25,11 @@
 #define SRAM_L2C_START(addr) SYMBOL(sram_l2c, addr)
 #define SRAM_L2C_END(addr) SYMBOL(esram_l2c, addr)
 
+#define DRAM_DMA(addr, size) \
+	REGION(dram_dma, addr, size, 4K) \
+	_ = ASSERT(size % 4K == 0, \
+		"DRAM DMA buffer should be multiple of smallest page size (4K)!");
+
 SECTIONS
 {
 	SRAM_L2C_START(0x000C0000)
@@ -44,6 +49,7 @@ SECTIONS
 	SRAM_END(0x00130000)
 
 	DRAM_START(0x40000000)
+	DRAM_DMA(0x40000000, 1M)
 	POSTRAM_CBFS_CACHE(0x40100000, 1M)
 	RAMSTAGE(0x40200000, 256K)
 }

src/soc/mediatek/mt8173/include/soc/mmu_operations.h

@@ -29,6 +29,10 @@ extern unsigned char _sram_l2c[];
 extern unsigned char _esram_l2c[];
 #define _sram_l2c_size (_esram_l2c - _sram_l2c)
 
+extern unsigned char _dram_dma[];
+extern unsigned char _edram_dma[];
+#define _dram_dma_size (_edram_dma - _dram_dma)
+
 void mt8173_mmu_init(void);
 void mt8173_mmu_after_dram(void);
 

src/soc/mediatek/mt8173/mmu_operations.c

@@ -53,6 +53,8 @@ void mt8173_mmu_after_dram(void)
 	/* TODO: Implement true unmapping, and also use it for the zero-page! */
 	mmu_config_range(_sram_l2c, _sram_l2c_size, DEV_MEM);
 
+	mmu_config_range(_dram_dma, _dram_dma_size, UNCACHED_MEM);
+
 	/* Careful: changing cache geometry while it's active is a bad idea! */
 	mmu_disable();