tegra: Add EMC support for optimal memory timings

Add support for setting up the memory controller parameters. Boards
can set up an appropriate table in the device tree.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>

3 files changed, 400 insertions, 0 deletions

diff --git a/arch/arm/cpu/armv7/tegra2/Makefile b/arch/arm/cpu/armv7/tegra2/Makefile
index e9ac6c9a71..dcd6329405 100644
--- a/arch/arm/cpu/armv7/tegra2/Makefile
+++ b/arch/arm/cpu/armv7/tegra2/Makefile
@@ -34,6 +34,7 @@ LIB	=  $(obj)lib$(SOC).o
 
 SOBJS	:= lowlevel_init.o
 COBJS-y	:= ap20.o board.o clock.o funcmux.o pinmux.o sys_info.o timer.o
+COBJS-$(CONFIG_TEGRA_CLOCK_SCALING) += emc.o
 COBJS-$(CONFIG_USB_EHCI_TEGRA) += usb.o
 
 COBJS	:= $(COBJS-y)
diff --git a/arch/arm/cpu/armv7/tegra2/emc.c b/arch/arm/cpu/armv7/tegra2/emc.c
new file mode 100644
index 0000000000..c0e5c565f1
--- /dev/null
+++ b/arch/arm/cpu/armv7/tegra2/emc.c
@@ -0,0 +1,286 @@
+/*
+ * Copyright (c) 2011 The Chromium OS Authors.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <fdtdec.h>
+#include <asm/io.h>
+#include <asm/arch/ap20.h>
+#include <asm/arch/apb_misc.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/emc.h>
+#include <asm/arch/tegra2.h>
+
+/*
+ * The EMC registers have shadow registers.  When the EMC clock is updated
+ * in the clock controller, the shadow registers are copied to the active
+ * registers, allowing glitchless memory bus frequency changes.
+ * This function updates the shadow registers for a new clock frequency,
+ * and relies on the clock lock on the emc clock to avoid races between
+ * multiple frequency changes
+ */
+
+/*
+ * This table defines the ordering of the registers provided to
+ * tegra_set_mmc()
+ * TODO: Convert to fdt version once available
+ */
+static const unsigned long emc_reg_addr[TEGRA_EMC_NUM_REGS] = {
+	0x2c,	/* RC */
+	0x30,	/* RFC */
+	0x34,	/* RAS */
+	0x38,	/* RP */
+	0x3c,	/* R2W */
+	0x40,	/* W2R */
+	0x44,	/* R2P */
+	0x48,	/* W2P */
+	0x4c,	/* RD_RCD */
+	0x50,	/* WR_RCD */
+	0x54,	/* RRD */
+	0x58,	/* REXT */
+	0x5c,	/* WDV */
+	0x60,	/* QUSE */
+	0x64,	/* QRST */
+	0x68,	/* QSAFE */
+	0x6c,	/* RDV */
+	0x70,	/* REFRESH */
+	0x74,	/* BURST_REFRESH_NUM */
+	0x78,	/* PDEX2WR */
+	0x7c,	/* PDEX2RD */
+	0x80,	/* PCHG2PDEN */
+	0x84,	/* ACT2PDEN */
+	0x88,	/* AR2PDEN */
+	0x8c,	/* RW2PDEN */
+	0x90,	/* TXSR */
+	0x94,	/* TCKE */
+	0x98,	/* TFAW */
+	0x9c,	/* TRPAB */
+	0xa0,	/* TCLKSTABLE */
+	0xa4,	/* TCLKSTOP */
+	0xa8,	/* TREFBW */
+	0xac,	/* QUSE_EXTRA */
+	0x114,	/* FBIO_CFG6 */
+	0xb0,	/* ODT_WRITE */
+	0xb4,	/* ODT_READ */
+	0x104,	/* FBIO_CFG5 */
+	0x2bc,	/* CFG_DIG_DLL */
+	0x2c0,	/* DLL_XFORM_DQS */
+	0x2c4,	/* DLL_XFORM_QUSE */
+	0x2e0,	/* ZCAL_REF_CNT */
+	0x2e4,	/* ZCAL_WAIT_CNT */
+	0x2a8,	/* AUTO_CAL_INTERVAL */
+	0x2d0,	/* CFG_CLKTRIM_0 */
+	0x2d4,	/* CFG_CLKTRIM_1 */
+	0x2d8,	/* CFG_CLKTRIM_2 */
+};
+
+struct emc_ctlr *emc_get_controller(const void *blob)
+{
+	fdt_addr_t addr;
+	int node;
+
+	node = fdtdec_next_compatible(blob, 0, COMPAT_NVIDIA_TEGRA20_EMC);
+	if (node > 0) {
+		addr = fdtdec_get_addr(blob, node, "reg");
+		if (addr != FDT_ADDR_T_NONE)
+			return (struct emc_ctlr *)addr;
+	}
+	return NULL;
+}
+
+/* Error codes we use */
+enum {
+	ERR_NO_EMC_NODE = -10,
+	ERR_NO_EMC_REG,
+	ERR_NO_FREQ,
+	ERR_FREQ_NOT_FOUND,
+	ERR_BAD_REGS,
+	ERR_NO_RAM_CODE,
+	ERR_RAM_CODE_NOT_FOUND,
+};
+
+/**
+ * Find EMC tables for the given ram code.
+ *
+ * The tegra EMC binding has two options, one using the ram code and one not.
+ * We detect which is in use by looking for the nvidia,use-ram-code property.
+ * If this is not present, then the EMC tables are directly below 'node',
+ * otherwise we select the correct emc-tables subnode based on the 'ram_code'
+ * value.
+ *
+ * @param blob		Device tree blob
+ * @param node		EMC node (nvidia,tegra20-emc compatible string)
+ * @param ram_code	RAM code to select (0-3, or -1 if unknown)
+ * @return 0 if ok, otherwise a -ve ERR_ code (see enum above)
+ */
+static int find_emc_tables(const void *blob, int node, int ram_code)
+{
+	int need_ram_code;
+	int depth;
+	int offset;
+
+	/* If we are using RAM codes, scan through the tables for our code */
+	need_ram_code = fdtdec_get_bool(blob, node, "nvidia,use-ram-code");
+	if (!need_ram_code)
+		return node;
+	if (ram_code == -1) {
+		debug("%s: RAM code required but not supplied\n", __func__);
+		return ERR_NO_RAM_CODE;
+	}
+
+	offset = node;
+	depth = 0;
+	do {
+		/*
+		 * Sadly there is no compatible string so we cannot use
+		 * fdtdec_next_compatible_subnode().
+		 */
+		offset = fdt_next_node(blob, offset, &depth);
+		if (depth <= 0)
+			break;
+
+		/* Make sure this is a direct subnode */
+		if (depth != 1)
+			continue;
+		if (strcmp("emc-tables", fdt_get_name(blob, offset, NULL)))
+			continue;
+
+		if (fdtdec_get_int(blob, offset, "nvidia,ram-code", -1)
+				== ram_code)
+			return offset;
+	} while (1);
+
+	debug("%s: Could not find tables for RAM code %d\n", __func__,
+	      ram_code);
+	return ERR_RAM_CODE_NOT_FOUND;
+}
+
+/**
+ * Decode the EMC node of the device tree, returning a pointer to the emc
+ * controller and the table to be used for the given rate.
+ *
+ * @param blob	Device tree blob
+ * @param rate	Clock speed of memory controller in Hz (=2x memory bus rate)
+ * @param emcp	Returns address of EMC controller registers
+ * @param tablep Returns pointer to table to program into EMC. There are
+ *		TEGRA_EMC_NUM_REGS entries, destined for offsets as per the
+ *		emc_reg_addr array.
+ * @return 0 if ok, otherwise a -ve error code which will allow someone to
+ * figure out roughly what went wrong by looking at this code.
+ */
+static int decode_emc(const void *blob, unsigned rate, struct emc_ctlr **emcp,
+		      const u32 **tablep)
+{
+	struct apb_misc_pp_ctlr *pp =
+		(struct apb_misc_pp_ctlr *)NV_PA_APB_MISC_BASE;
+	int ram_code;
+	int depth;
+	int node;
+
+	ram_code = (readl(&pp->strapping_opt_a) & RAM_CODE_MASK)
+			>> RAM_CODE_SHIFT;
+	/*
+	 * The EMC clock rate is twice the bus rate, and the bus rate is
+	 * measured in kHz
+	 */
+	rate = rate / 2 / 1000;
+
+	node = fdtdec_next_compatible(blob, 0, COMPAT_NVIDIA_TEGRA20_EMC);
+	if (node < 0) {
+		debug("%s: No EMC node found in FDT\n", __func__);
+		return ERR_NO_EMC_NODE;
+	}
+	*emcp = (struct emc_ctlr *)fdtdec_get_addr(blob, node, "reg");
+	if (*emcp == (struct emc_ctlr *)FDT_ADDR_T_NONE) {
+		debug("%s: No EMC node reg property\n", __func__);
+		return ERR_NO_EMC_REG;
+	}
+
+	/* Work out the parent node which contains our EMC tables */
+	node = find_emc_tables(blob, node, ram_code & 3);
+	if (node < 0)
+		return node;
+
+	depth = 0;
+	for (;;) {
+		int node_rate;
+
+		node = fdtdec_next_compatible_subnode(blob, node,
+				COMPAT_NVIDIA_TEGRA20_EMC_TABLE, &depth);
+		if (node < 0)
+			break;
+		node_rate = fdtdec_get_int(blob, node, "clock-frequency", -1);
+		if (node_rate == -1) {
+			debug("%s: Missing clock-frequency\n", __func__);
+			return ERR_NO_FREQ; /* we expect this property */
+		}
+
+		if (node_rate == rate)
+			break;
+	}
+	if (node < 0) {
+		debug("%s: No node found for clock frequency %d\n", __func__,
+		      rate);
+		return ERR_FREQ_NOT_FOUND;
+	}
+
+	*tablep = fdtdec_locate_array(blob, node, "nvidia,emc-registers",
+				      TEGRA_EMC_NUM_REGS);
+	if (!*tablep) {
+		debug("%s: node '%s' array missing / wrong size\n", __func__,
+		      fdt_get_name(blob, node, NULL));
+		return ERR_BAD_REGS;
+	}
+
+	/* All seems well */
+	return 0;
+}
+
+int tegra_set_emc(const void *blob, unsigned rate)
+{
+	struct emc_ctlr *emc;
+	const u32 *table;
+	int err, i;
+
+	err = decode_emc(blob, rate, &emc, &table);
+	if (err) {
+		debug("Warning: no valid EMC (%d), memory timings unset\n",
+		       err);
+		return err;
+	}
+
+	debug("%s: Table found, setting EMC values as follows:\n", __func__);
+	for (i = 0; i < TEGRA_EMC_NUM_REGS; i++) {
+		u32 value = fdt32_to_cpu(table[i]);
+		u32 addr = (uintptr_t)emc + emc_reg_addr[i];
+
+		debug("   %#x: %#x\n", addr, value);
+		writel(value, addr);
+	}
+
+	/* trigger emc with new settings */
+	clock_adjust_periph_pll_div(PERIPH_ID_EMC, CLOCK_ID_MEMORY,
+				clock_get_rate(CLOCK_ID_MEMORY), NULL);
+	debug("EMC clock set to %lu\n",
+	      clock_get_periph_rate(PERIPH_ID_EMC, CLOCK_ID_MEMORY));
+
+	return 0;
+}
diff --git a/arch/arm/include/asm/arch-tegra2/emc.h b/arch/arm/include/asm/arch-tegra2/emc.h
new file mode 100644
index 0000000000..deb3d36ed2
--- /dev/null
+++ b/arch/arm/include/asm/arch-tegra2/emc.h
@@ -0,0 +1,113 @@
+/*
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * (C) Copyright 2010,2011 NVIDIA Corporation <www.nvidia.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef _ARCH_EMC_H_
+#define _ARCH_EMC_H_
+
+#include <asm/types.h>
+
+#define TEGRA_EMC_NUM_REGS	46
+
+/* EMC Registers */
+struct emc_ctlr {
+	u32 cfg;		/* 0x00: EMC_CFG */
+	u32 reserved0[3];	/* 0x04 ~ 0x0C */
+	u32 adr_cfg;		/* 0x10: EMC_ADR_CFG */
+	u32 adr_cfg1;		/* 0x14: EMC_ADR_CFG_1 */
+	u32 reserved1[2];	/* 0x18 ~ 0x18 */
+	u32 refresh_ctrl;	/* 0x20: EMC_REFCTRL */
+	u32 pin;		/* 0x24: EMC_PIN */
+	u32 timing_ctrl;	/* 0x28: EMC_TIMING_CONTROL */
+	u32 rc;			/* 0x2C: EMC_RC */
+	u32 rfc;		/* 0x30: EMC_RFC */
+	u32 ras;		/* 0x34: EMC_RAS */
+	u32 rp;			/* 0x38: EMC_RP */
+	u32 r2w;		/* 0x3C: EMC_R2W */
+	u32 w2r;		/* 0x40: EMC_W2R */
+	u32 r2p;		/* 0x44: EMC_R2P */
+	u32 w2p;		/* 0x48: EMC_W2P */
+	u32 rd_rcd;		/* 0x4C: EMC_RD_RCD */
+	u32 wd_rcd;		/* 0x50: EMC_WD_RCD */
+	u32 rrd;		/* 0x54: EMC_RRD */
+	u32 rext;		/* 0x58: EMC_REXT */
+	u32 wdv;		/* 0x5C: EMC_WDV */
+	u32 quse;		/* 0x60: EMC_QUSE */
+	u32 qrst;		/* 0x64: EMC_QRST */
+	u32 qsafe;		/* 0x68: EMC_QSAFE */
+	u32 rdv;		/* 0x6C: EMC_RDV */
+	u32 refresh;		/* 0x70: EMC_REFRESH */
+	u32 burst_refresh_num;	/* 0x74: EMC_BURST_REFRESH_NUM */
+	u32 pdex2wr;		/* 0x78: EMC_PDEX2WR */
+	u32 pdex2rd;		/* 0x7c: EMC_PDEX2RD */
+	u32 pchg2pden;		/* 0x80: EMC_PCHG2PDEN */
+	u32 act2pden;		/* 0x84: EMC_ACT2PDEN */
+	u32 ar2pden;		/* 0x88: EMC_AR2PDEN */
+	u32 rw2pden;		/* 0x8C: EMC_RW2PDEN */
+	u32 txsr;		/* 0x90: EMC_TXSR */
+	u32 tcke;		/* 0x94: EMC_TCKE */
+	u32 tfaw;		/* 0x98: EMC_TFAW */
+	u32 trpab;		/* 0x9C: EMC_TRPAB */
+	u32 tclkstable;		/* 0xA0: EMC_TCLKSTABLE */
+	u32 tclkstop;		/* 0xA4: EMC_TCLKSTOP */
+	u32 trefbw;		/* 0xA8: EMC_TREFBW */
+	u32 quse_extra;		/* 0xAC: EMC_QUSE_EXTRA */
+	u32 odt_write;		/* 0xB0: EMC_ODT_WRITE */
+	u32 odt_read;		/* 0xB4: EMC_ODT_READ */
+	u32 reserved2[5];	/* 0xB8 ~ 0xC8 */
+	u32 mrs;		/* 0xCC: EMC_MRS */
+	u32 emrs;		/* 0xD0: EMC_EMRS */
+	u32 ref;		/* 0xD4: EMC_REF */
+	u32 pre;		/* 0xD8: EMC_PRE */
+	u32 nop;		/* 0xDC: EMC_NOP */
+	u32 self_ref;		/* 0xE0: EMC_SELF_REF */
+	u32 dpd;		/* 0xE4: EMC_DPD */
+	u32 mrw;		/* 0xE8: EMC_MRW */
+	u32 mrr;		/* 0xEC: EMC_MRR */
+	u32 reserved3;		/* 0xF0: */
+	u32 fbio_cfg1;		/* 0xF4: EMC_FBIO_CFG1 */
+	u32 fbio_dqsib_dly;	/* 0xF8: EMC_FBIO_DQSIB_DLY */
+	u32 fbio_dqsib_dly_msb;	/* 0xFC: EMC_FBIO_DQSIB_DLY_MSG */
+	u32 fbio_spare;		/* 0x100: SBIO_SPARE */
+				/* There are more registers ... */
+};
+
+/**
+ * Set up the EMC for the given rate. The timing parameters are retrieved
+ * from the device tree "nvidia,tegra20-emc" node and its
+ * "nvidia,tegra20-emc-table" sub-nodes.
+ *
+ * @param blob	Device tree blob
+ * @param rate	Clock speed of memory controller in Hz (=2x memory bus rate)
+ * @return 0 if ok, else -ve error code (look in emc.c to decode it)
+ */
+int tegra_set_emc(const void *blob, unsigned rate);
+
+/**
+ * Get a pointer to the EMC controller from the device tree.
+ *
+ * @param blob	Device tree blob
+ * @return pointer to EMC controller
+ */
+struct emc_ctlr *emc_get_controller(const void *blob);
+
+#endif