Add (parts of the) support for multiple DIMMs on the Intel 440BX chipset.

This is tested on hardware with four 128MB DIMMs and works ok, _iff_
you also fix additional registers (e.g. DRB, RPS, ...) for your setup.
This requirement will be eliminated in another upcoming patch (i.e. all
of the required settings will be auto-detected).

Signed-off-by: Uwe Hermann <uwe@hermann-uwe.de>
Acked-by: Joseph Smith <joe@settoplinux.org>



git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3807 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

1 files changed, 63 insertions, 32 deletions

diff --git a/src/northbridge/intel/i440bx/raminit.c b/src/northbridge/intel/i440bx/raminit.c
index b3bea6b5f3..5c560e17de 100644
--- a/src/northbridge/intel/i440bx/raminit.c
+++ b/src/northbridge/intel/i440bx/raminit.c
@@ -352,34 +352,66 @@ SDRAM configuration functions.
 /**
  * Send the specified RAM command to all DIMMs.
  *
- * @param TODO
- * @param TODO
+ * @param command The RAM command to send to the DIMM(s).
  */
-static void do_ram_command(uint32_t command, uint32_t addr_offset)
+static void do_ram_command(u32 command)
 {
-	int i;
-	uint16_t reg;
-
-	/* TODO: Support for multiple DIMMs. */
+	int i, caslatency;
+	u8 dimm_start, dimm_end;
+	u16 reg16;
+	u32 addr, addr_offset;
 
 	/* Configure the RAM command. */
-	reg = pci_read_config16(NB, SDRAMC);
-	reg &= 0xff1f;		/* Clear bits 7-5. */
-	reg |= (uint16_t) (command << 5);
-	pci_write_config16(NB, SDRAMC, reg);
-
-	/* RAM_COMMAND_NORMAL affects only the memory controller and
-	   doesn't need to be "sent" to the DIMMs. */
-	/* if (command == RAM_COMMAND_NORMAL) return; */
-
-	PRINT_DEBUG("    Sending RAM command 0x");
-	PRINT_DEBUG_HEX16(reg);
-	PRINT_DEBUG(" to 0x");
-	PRINT_DEBUG_HEX32(0 + addr_offset); // FIXME
-	PRINT_DEBUG("\r\n");
-
-	/* Read from (DIMM start address + addr_offset). */
-	read32(0 + addr_offset); // FIXME
+	reg16 = pci_read_config16(NB, SDRAMC);
+	reg16 &= 0xff1f;		/* Clear bits 7-5. */
+	reg16 |= (u16) (command << 5);	/* Write command into bits 7-5. */
+	pci_write_config16(NB, SDRAMC, reg16);
+
+	/*
+	 * RAM_COMMAND_NORMAL affects only the memory controller and
+	 * doesn't need to be "sent" to the DIMMs.
+	 */
+	if (command == RAM_COMMAND_NORMAL)
+		return;
+
+	/* Send the RAM command to each row of memory. */
+	dimm_start = 0;
+	for (i = 0; i < (DIMM_SOCKETS * 2); i++) {
+                addr_offset = 0;
+                caslatency = 3; /* TODO: Dynamically get CAS latency later. */
+		if (command == RAM_COMMAND_MRS) {
+			/*
+			 * MAA[12:11,9:0] must be inverted when sent to DIMM
+			 * 2 or 3 (no inversion if sent to DIMM 0 or 1).
+			 */
+			if ((i >= 0 && i <= 3) && caslatency == 3)
+				addr_offset = 0x1d0;
+			if ((i >= 4 && i <= 7) && caslatency == 3)
+				addr_offset = 0x1e28;
+			if ((i >= 0 && i <= 3) && caslatency == 2)
+				addr_offset = 0x150;
+			if ((i >= 4 && i <= 7) && caslatency == 2)
+				addr_offset = 0x1ea8;
+		}
+
+		dimm_end = pci_read_config8(NB, DRB + i);
+
+		addr = (dimm_start * 8 * 1024 * 1024) + addr_offset;
+		if (dimm_end > dimm_start) {
+#if 0
+			PRINT_DEBUG("    Sending RAM command 0x");
+			PRINT_DEBUG_HEX16(reg16);
+			PRINT_DEBUG(" to 0x");
+			PRINT_DEBUG_HEX32(addr);
+			PRINT_DEBUG("\r\n");
+#endif
+
+			read32(addr);
+		}
+
+		/* Set the start of the next DIMM. */
+		dimm_start = dimm_end;
+	}
 }
 
 /*-----------------------------------------------------------------------------
@@ -469,12 +501,11 @@ static void sdram_set_spd_registers(void)
 	/* TODO: Set DRAMC. Don't enable refresh for now. */
 	pci_write_config8(NB, DRAMC, 0x08);
 
-	/* TODO: Set RPS. */
+	/* TODO: Set RPS. Needs to be fixed for multiple DIMM support. */
 	pci_write_config16(NB, RPS, 0x0001);
 
 	/* TODO: Set SDRAMC. */
-	// pci_write_config16(NB, SDRAMC, 0x010f); // FIXME?
-	pci_write_config16(NB, SDRAMC, 0x0003); // FIXME?
+	pci_write_config16(NB, SDRAMC, 0x0010);	/* SDRAMPWR=1: 4 DIMM config */
 
 	/* TODO: Set PGPOL. */
 	// pci_write_config16(NB, PGPOL, 0x0107);
@@ -504,29 +535,29 @@ static void sdram_enable(void)
 
 	/* 1. Apply NOP. Wait 200 clock cycles (200us should do). */
 	PRINT_DEBUG("RAM Enable 1: Apply NOP\r\n");
-	do_ram_command(RAM_COMMAND_NOP, 0);
+	do_ram_command(RAM_COMMAND_NOP);
 	udelay(200);
 
 	/* 2. Precharge all. Wait tRP. */
 	PRINT_DEBUG("RAM Enable 2: Precharge all\r\n");
-	do_ram_command(RAM_COMMAND_PRECHARGE, 0);
+	do_ram_command(RAM_COMMAND_PRECHARGE);
 	udelay(1);
 
 	/* 3. Perform 8 refresh cycles. Wait tRC each time. */
 	PRINT_DEBUG("RAM Enable 3: CBR\r\n");
 	for (i = 0; i < 8; i++) {
-		do_ram_command(RAM_COMMAND_CBR, 0);
+		do_ram_command(RAM_COMMAND_CBR);
 		udelay(1);
 	}
 
 	/* 4. Mode register set. Wait two memory cycles. */
 	PRINT_DEBUG("RAM Enable 4: Mode register set\r\n");
-	do_ram_command(RAM_COMMAND_MRS, 0x1d0);
+	do_ram_command(RAM_COMMAND_MRS);
 	udelay(2);
 
 	/* 5. Normal operation. */
 	PRINT_DEBUG("RAM Enable 5: Normal operation\r\n");
-	do_ram_command(RAM_COMMAND_NORMAL, 0);
+	do_ram_command(RAM_COMMAND_NORMAL);
 	udelay(1);
 
 	/* 6. Finally enable refresh. */