drivers: ddr: Add DDR2 SDRAM controller driver for Microchip PIC32.

This driver initializes PIC32 DDR2 SDRAM controller and internal DDR2 Phy module.
DDR2 controller operates in half-rate mode (upto 533MHZ frequency).

Signed-off-by: Paul Thacker <paul.thacker@microchip.com>
Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

4 files changed, 497 insertions, 0 deletions

diff --git a/drivers/ddr/microchip/Makefile b/drivers/ddr/microchip/Makefile
new file mode 100644
index 0000000000..305c48b164
--- /dev/null
+++ b/drivers/ddr/microchip/Makefile
@@ -0,0 +1,6 @@
+#
+# Copyright (C) 2015 Microchip Technology Inc.
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+obj-$(CONFIG_MACH_PIC32) += ddr2.o
diff --git a/drivers/ddr/microchip/ddr2.c b/drivers/ddr/microchip/ddr2.c
new file mode 100644
index 0000000000..6056418588
--- /dev/null
+++ b/drivers/ddr/microchip/ddr2.c
@@ -0,0 +1,278 @@
+/*
+ * (c) 2015 Paul Thacker <paul.thacker@microchip.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ *
+ */
+#include <common.h>
+#include <wait_bit.h>
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <mach/pic32.h>
+#include <mach/ddr.h>
+
+#include "ddr2_regs.h"
+#include "ddr2_timing.h"
+
+/* init DDR2 Phy */
+void ddr2_phy_init(void)
+{
+	struct ddr2_phy_regs *ddr2_phy;
+	u32 pad_ctl;
+
+	ddr2_phy = ioremap(PIC32_DDR2P_BASE, sizeof(*ddr2_phy));
+
+	/* PHY_DLL_RECALIB */
+	writel(DELAY_START_VAL(3) | DISABLE_RECALIB(0) |
+	       RECALIB_CNT(0x10), &ddr2_phy->dll_recalib);
+
+	/* PHY_PAD_CTRL */
+	pad_ctl = ODT_SEL | ODT_EN | DRIVE_SEL(0) |
+		  ODT_PULLDOWN(2) | ODT_PULLUP(3) |
+		  EXTRA_OEN_CLK(0) | NOEXT_DLL |
+		  DLR_DFT_WRCMD | HALF_RATE |
+		  DRVSTR_PFET(0xe) | DRVSTR_NFET(0xe) |
+		  RCVR_EN | PREAMBLE_DLY(2);
+	writel(pad_ctl, &ddr2_phy->pad_ctrl);
+
+	/* SCL_CONFIG_0 */
+	writel(SCL_BURST8 | SCL_DDR_CONNECTED | SCL_RCAS_LAT(RL) |
+	       SCL_ODTCSWW, &ddr2_phy->scl_config_1);
+
+	/* SCL_CONFIG_1 */
+	writel(SCL_CSEN | SCL_WCAS_LAT(WL), &ddr2_phy->scl_config_2);
+
+	/* SCL_LAT */
+	writel(SCL_CAPCLKDLY(3) | SCL_DDRCLKDLY(4), &ddr2_phy->scl_latency);
+}
+
+/* start phy self calibration logic */
+static int ddr2_phy_calib_start(void)
+{
+	struct ddr2_phy_regs *ddr2_phy;
+
+	ddr2_phy = ioremap(PIC32_DDR2P_BASE, sizeof(*ddr2_phy));
+
+	/* DDR Phy SCL Start */
+	writel(SCL_START | SCL_EN, &ddr2_phy->scl_start);
+
+	/* Wait for SCL for data byte to pass */
+	return wait_for_bit(__func__, &ddr2_phy->scl_start, SCL_LUBPASS,
+			    true, CONFIG_SYS_HZ, false);
+}
+
+/* DDR2 Controller initialization */
+
+/* Target Agent Arbiter */
+static void ddr_set_arbiter(struct ddr2_ctrl_regs *ctrl,
+			    const struct ddr2_arbiter_params *const param)
+{
+	int i;
+
+	for (i = 0; i < NUM_AGENTS; i++) {
+		/* set min burst size */
+		writel(i * MIN_LIM_WIDTH, &ctrl->tsel);
+		writel(param->min_limit, &ctrl->minlim);
+
+		/* set request period (4 * req_period clocks) */
+		writel(i * RQST_PERIOD_WIDTH, &ctrl->tsel);
+		writel(param->req_period, &ctrl->reqprd);
+
+		/* set number of burst accepted */
+		writel(i * MIN_CMDACPT_WIDTH, &ctrl->tsel);
+		writel(param->min_cmd_acpt, &ctrl->mincmd);
+	}
+}
+
+const struct ddr2_arbiter_params *__weak board_get_ddr_arbiter_params(void)
+{
+	/* default arbiter parameters */
+	static const struct ddr2_arbiter_params arb_params[] = {
+		{ .min_limit = 0x1f, .req_period = 0xff, .min_cmd_acpt = 0x04,},
+		{ .min_limit = 0x1f, .req_period = 0xff, .min_cmd_acpt = 0x10,},
+		{ .min_limit = 0x1f, .req_period = 0xff, .min_cmd_acpt = 0x10,},
+		{ .min_limit = 0x04, .req_period = 0xff, .min_cmd_acpt = 0x04,},
+		{ .min_limit = 0x04, .req_period = 0xff, .min_cmd_acpt = 0x04,},
+	};
+
+	return &arb_params[0];
+}
+
+static void host_load_cmd(struct ddr2_ctrl_regs *ctrl, u32 cmd_idx,
+			  u32 hostcmd2, u32 hostcmd1, u32 delay)
+{
+	u32 hc_delay;
+
+	hc_delay = max_t(u32, DIV_ROUND_UP(delay, T_CK), 2) - 2;
+	writel(hostcmd1, &ctrl->cmd10[cmd_idx]);
+	writel((hostcmd2 & 0x7ff) | (hc_delay << 11), &ctrl->cmd20[cmd_idx]);
+}
+
+/* init DDR2 Controller */
+void ddr2_ctrl_init(void)
+{
+	u32 wr2prech, rd2prech, wr2rd, wr2rd_cs;
+	u32 ras2ras, ras2cas, prech2ras, temp;
+	const struct ddr2_arbiter_params *arb_params;
+	struct ddr2_ctrl_regs *ctrl;
+
+	ctrl = ioremap(PIC32_DDR2C_BASE, sizeof(*ctrl));
+
+	/* PIC32 DDR2 controller always work in HALF_RATE */
+	writel(HALF_RATE_MODE, &ctrl->memwidth);
+
+	/* Set arbiter configuration per target */
+	arb_params = board_get_ddr_arbiter_params();
+	ddr_set_arbiter(ctrl, arb_params);
+
+	/* Address Configuration, model {CS, ROW, BA, COL} */
+	writel((ROW_ADDR_RSHIFT | (BA_RSHFT << 8) | (CS_ADDR_RSHIFT << 16) |
+	       (COL_HI_RSHFT << 24) | (SB_PRI << 29)  |
+	       (EN_AUTO_PRECH << 30)), &ctrl->memcfg0);
+
+	writel(ROW_ADDR_MASK, &ctrl->memcfg1);
+	writel(COL_HI_MASK, &ctrl->memcfg2);
+	writel(COL_LO_MASK, &ctrl->memcfg3);
+	writel(BA_MASK | (CS_ADDR_MASK << 8), &ctrl->memcfg4);
+
+	/* Refresh Config */
+	writel(REFCNT_CLK(DIV_ROUND_UP(T_RFI, T_CK_CTRL) - 2) |
+	       REFDLY_CLK(DIV_ROUND_UP(T_RFC_MIN, T_CK_CTRL) - 2) |
+	       MAX_PEND_REF(7),
+	       &ctrl->refcfg);
+
+	/* Power Config */
+	writel(ECC_EN(0) | ERR_CORR_EN(0) | EN_AUTO_PWR_DN(0) |
+	       EN_AUTO_SELF_REF(3) | PWR_DN_DLY(8) |
+	       SELF_REF_DLY(17) | PRECH_PWR_DN_ONLY(0),
+	       &ctrl->pwrcfg);
+
+	/* Delay Config */
+	wr2rd = max_t(u32, DIV_ROUND_UP(T_WTR, T_CK_CTRL),
+		      DIV_ROUND_UP(T_WTR_TCK, 2)) + WL + BL;
+	wr2rd_cs = max_t(u32, wr2rd - 1, 3);
+	wr2prech = DIV_ROUND_UP(T_WR, T_CK_CTRL) + WL + BL;
+	rd2prech = max_t(u32, DIV_ROUND_UP(T_RTP, T_CK_CTRL),
+			 DIV_ROUND_UP(T_RTP_TCK, 2)) + BL - 2;
+	ras2ras = max_t(u32, DIV_ROUND_UP(T_RRD, T_CK_CTRL),
+			DIV_ROUND_UP(T_RRD_TCK, 2)) - 1;
+	ras2cas = DIV_ROUND_UP(T_RCD, T_CK_CTRL) - 1;
+	prech2ras = DIV_ROUND_UP(T_RP, T_CK_CTRL) - 1;
+
+	writel(((wr2rd & 0x0f) |
+	       ((wr2rd_cs & 0x0f) << 4) |
+	       ((BL - 1) << 8) |
+	       (BL << 12) |
+	       ((BL - 1) << 16) |
+	       ((BL - 1) << 20) |
+	       ((BL + 2) << 24) |
+	       ((RL - WL + 3) << 28)), &ctrl->dlycfg0);
+
+	writel(((T_CKE_TCK - 1) |
+	       (((DIV_ROUND_UP(T_DLLK, 2) - 2) & 0xff) << 8) |
+	       ((T_CKE_TCK - 1) << 16) |
+	       ((max_t(u32, T_XP_TCK, T_CKE_TCK) - 1) << 20) |
+	       ((wr2prech >> 4) << 26) |
+	       ((wr2rd >> 4) << 27) |
+	       ((wr2rd_cs >> 4) << 28) |
+	       (((RL + 5) >> 4) << 29) |
+	       ((DIV_ROUND_UP(T_DLLK, 2) >> 8) << 30)), &ctrl->dlycfg1);
+
+	writel((DIV_ROUND_UP(T_RP, T_CK_CTRL) |
+	       (rd2prech << 8) |
+	       ((wr2prech & 0x0f) << 12) |
+	       (ras2ras << 16) |
+	       (ras2cas << 20) |
+	       (prech2ras << 24) |
+	       ((RL + 3) << 28)), &ctrl->dlycfg2);
+
+	writel(((DIV_ROUND_UP(T_RAS_MIN, T_CK_CTRL) - 1) |
+	       ((DIV_ROUND_UP(T_RC, T_CK_CTRL) - 1) << 8) |
+	       ((DIV_ROUND_UP(T_FAW, T_CK_CTRL) - 1) << 16)),
+	       &ctrl->dlycfg3);
+
+	/* ODT Config */
+	writel(0x0, &ctrl->odtcfg);
+	writel(BIT(16), &ctrl->odtencfg);
+	writel(ODTRDLY(RL - 3) | ODTWDLY(WL - 3) | ODTRLEN(2) | ODTWLEN(3),
+	       &ctrl->odtcfg);
+
+	/* Transfer Configuration */
+	writel(NXTDATRQDLY(2) | NXDATAVDLY(4) | RDATENDLY(2) |
+	       MAX_BURST(3) | (7 << 28) | BIG_ENDIAN(0),
+	       &ctrl->xfercfg);
+
+	/* DRAM Initialization */
+	/* CKE high after reset and wait 400 nsec */
+	host_load_cmd(ctrl, 0, 0, IDLE_NOP, 400000);
+
+	/* issue precharge all command */
+	host_load_cmd(ctrl, 1, 0x04, PRECH_ALL_CMD, T_RP + T_CK);
+
+	/* initialize EMR2 */
+	host_load_cmd(ctrl, 2, 0x200, LOAD_MODE_CMD, T_MRD_TCK * T_CK);
+
+	/* initialize EMR3 */
+	host_load_cmd(ctrl, 3, 0x300, LOAD_MODE_CMD, T_MRD_TCK * T_CK);
+
+	/*
+	 * RDQS disable, DQSB enable, OCD exit, 150 ohm termination,
+	 * AL=0, DLL enable
+	 */
+	host_load_cmd(ctrl, 4, 0x100,
+		      LOAD_MODE_CMD | (0x40 << 24), T_MRD_TCK * T_CK);
+	/*
+	 * PD fast exit, WR REC = T_WR in clocks -1,
+	 * DLL reset, CAS = RL, burst = 4
+	 */
+	temp = ((DIV_ROUND_UP(T_WR, T_CK) - 1) << 1) | 1;
+	host_load_cmd(ctrl, 5, temp, LOAD_MODE_CMD | (RL << 28) | (2 << 24),
+		      T_MRD_TCK * T_CK);
+
+	/* issue precharge all command */
+	host_load_cmd(ctrl, 6, 4, PRECH_ALL_CMD, T_RP + T_CK);
+
+	/* issue refresh command */
+	host_load_cmd(ctrl, 7, 0, REF_CMD, T_RFC_MIN);
+
+	/* issue refresh command */
+	host_load_cmd(ctrl, 8, 0, REF_CMD, T_RFC_MIN);
+
+	/* Mode register programming as before without DLL reset */
+	host_load_cmd(ctrl, 9, temp, LOAD_MODE_CMD | (RL << 28) | (3 << 24),
+		      T_MRD_TCK * T_CK);
+
+	/* extended mode register same as before with OCD default */
+	host_load_cmd(ctrl, 10, 0x103, LOAD_MODE_CMD | (0xc << 24),
+		      T_MRD_TCK * T_CK);
+
+	/* extended mode register same as before with OCD exit */
+	host_load_cmd(ctrl, 11, 0x100, LOAD_MODE_CMD | (0x4 << 28),
+		      140 * T_CK);
+
+	writel(CMD_VALID | NUMHOSTCMD(11), &ctrl->cmdissue);
+
+	/* start memory initialization */
+	writel(INIT_START, &ctrl->memcon);
+
+	/* wait for all host cmds to be transmitted */
+	wait_for_bit(__func__, &ctrl->cmdissue, CMD_VALID, false,
+		     CONFIG_SYS_HZ, false);
+
+	/* inform all cmds issued, ready for normal operation */
+	writel(INIT_START | INIT_DONE, &ctrl->memcon);
+
+	/* perform phy caliberation */
+	if (ddr2_phy_calib_start())
+		printf("ddr2: phy calib failed\n");
+}
+
+phys_size_t ddr2_calculate_size(void)
+{
+	u32 temp;
+
+	temp = 1 << (COL_BITS + BA_BITS + ROW_BITS);
+	/* 16-bit data width between controller and DIMM */
+	temp = temp * CS_BITS * (16 / 8);
+	return (phys_size_t)temp;
+}
diff --git a/drivers/ddr/microchip/ddr2_regs.h b/drivers/ddr/microchip/ddr2_regs.h
new file mode 100644
index 0000000000..0f4b159048
--- /dev/null
+++ b/drivers/ddr/microchip/ddr2_regs.h
@@ -0,0 +1,148 @@
+/*
+ * (c) 2015 Purna Chandra Mandal <purna.mandal@microchip.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ *
+ */
+
+#ifndef __MICROCHIP_DDR2_REGS_H
+#define __MICROCHIP_DDR2_REGS_H
+
+#include <linux/bitops.h>
+
+/* DDR2 Controller */
+struct ddr2_ctrl_regs {
+	u32 tsel;
+	u32 minlim;
+	u32 reqprd;
+	u32 mincmd;
+	u32 memcon;
+	u32 memcfg0;
+	u32 memcfg1;
+	u32 memcfg2;
+	u32 memcfg3;
+	u32 memcfg4;
+	u32 refcfg;
+	u32 pwrcfg;
+	u32 dlycfg0;
+	u32 dlycfg1;
+	u32 dlycfg2;
+	u32 dlycfg3;
+	u32 odtcfg;
+	u32 xfercfg;
+	u32 cmdissue;
+	u32 odtencfg;
+	u32 memwidth;
+	u32 unused[11];
+	u32 cmd10[16];
+	u32 cmd20[16];
+};
+
+/* Arbiter Config */
+#define MIN_LIM_WIDTH		5
+#define RQST_PERIOD_WIDTH	8
+#define MIN_CMDACPT_WIDTH	8
+
+/* Refresh Config */
+#define REFCNT_CLK(x)		(x)
+#define REFDLY_CLK(x)		((x) << 16)
+#define MAX_PEND_REF(x)		((x) << 24)
+
+/* Power Config */
+#define PRECH_PWR_DN_ONLY(x)	((x) << 22)
+#define SELF_REF_DLY(x)		((x) << 12)
+#define PWR_DN_DLY(x)		((x) << 4)
+#define EN_AUTO_SELF_REF(x)	((x) << 3)
+#define EN_AUTO_PWR_DN(x)	((x) << 2)
+#define ERR_CORR_EN(x)		((x) << 1)
+#define ECC_EN(x)		(x)
+
+/* Memory Width */
+#define HALF_RATE_MODE		BIT(3)
+
+/* Delay Config */
+#define ODTWLEN(x)	((x) << 20)
+#define ODTRLEN(x)	((x) << 16)
+#define ODTWDLY(x)	((x) << 12)
+#define ODTRDLY(x)	((x) << 8)
+
+/* Xfer Config */
+#define BIG_ENDIAN(x)	((x) << 31)
+#define MAX_BURST(x)	((x) << 24)
+#define RDATENDLY(x)	((x) << 16)
+#define NXDATAVDLY(x)	((x) << 4)
+#define NXTDATRQDLY(x)	((x) << 0)
+
+/* Host Commands */
+#define IDLE_NOP	0x00ffffff
+#define PRECH_ALL_CMD	0x00fff401
+#define REF_CMD		0x00fff801
+#define LOAD_MODE_CMD	0x00fff001
+#define CKE_LOW		0x00ffeffe
+
+#define NUM_HOST_CMDS	12
+
+/* Host CMD Issue */
+#define CMD_VALID	BIT(4)
+#define NUMHOSTCMD(x)	(x)
+
+/* Memory Control */
+#define INIT_DONE	BIT(1)
+#define INIT_START	BIT(0)
+
+/* Address Control */
+#define EN_AUTO_PRECH		0
+#define SB_PRI			1
+
+/* DDR2 Phy Register */
+struct ddr2_phy_regs {
+	u32 scl_start;
+	u32 unused1[2];
+	u32 scl_latency;
+	u32 unused2[2];
+	u32 scl_config_1;
+	u32 scl_config_2;
+	u32 pad_ctrl;
+	u32 dll_recalib;
+};
+
+/* PHY PAD CONTROL */
+#define ODT_SEL			BIT(0)
+#define ODT_EN			BIT(1)
+#define DRIVE_SEL(x)		((x) << 2)
+#define ODT_PULLDOWN(x)		((x) << 4)
+#define ODT_PULLUP(x)		((x) << 6)
+#define EXTRA_OEN_CLK(x)	((x) << 8)
+#define NOEXT_DLL		BIT(9)
+#define DLR_DFT_WRCMD		BIT(13)
+#define HALF_RATE		BIT(14)
+#define DRVSTR_PFET(x)		((x) << 16)
+#define DRVSTR_NFET(x)		((x) << 20)
+#define RCVR_EN			BIT(28)
+#define PREAMBLE_DLY(x)		((x) << 29)
+
+/* PHY DLL RECALIBRATE */
+#define RECALIB_CNT(x)		((x) << 8)
+#define DISABLE_RECALIB(x)	((x) << 26)
+#define DELAY_START_VAL(x)	((x) << 28)
+
+/* PHY SCL CONFIG1 */
+#define SCL_BURST8		BIT(0)
+#define SCL_DDR_CONNECTED		BIT(1)
+#define SCL_RCAS_LAT(x)		((x) << 4)
+#define SCL_ODTCSWW		BIT(24)
+
+/* PHY SCL CONFIG2 */
+#define SCL_CSEN		BIT(0)
+#define SCL_WCAS_LAT(x)		((x) << 8)
+
+/* PHY SCL Latency */
+#define SCL_CAPCLKDLY(x)	((x) << 0)
+#define SCL_DDRCLKDLY(x)	((x) << 4)
+
+/* PHY SCL START */
+#define SCL_START		BIT(28)
+#define SCL_EN			BIT(26)
+#define SCL_LUBPASS		(BIT(1) | BIT(0))
+
+#endif	/* __MICROCHIP_DDR2_REGS_H */
diff --git a/drivers/ddr/microchip/ddr2_timing.h b/drivers/ddr/microchip/ddr2_timing.h
new file mode 100644
index 0000000000..5895f9d592
--- /dev/null
+++ b/drivers/ddr/microchip/ddr2_timing.h
@@ -0,0 +1,65 @@
+/*
+ * (c) 2015 Purna Chandra Mandal <purna.mandal@microchip.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ *
+ */
+
+#ifndef __MICROCHIP_DDR2_TIMING_H
+#define __MICROCHIP_DDR2_TIMING_H
+
+/* MPLL freq is 400MHz */
+#define T_CK		2500    /* 2500 psec */
+#define T_CK_CTRL	(T_CK * 2)
+
+/* Burst length in cycles */
+#define BL		2
+/* default CAS latency for all speed grades */
+#define RL		5
+/* default write latency for all speed grades = CL-1 */
+#define WL		4
+
+/* From Micron MT47H64M16HR-3 data sheet */
+#define T_RFC_MIN	127500	/* psec */
+#define T_WR		15000	/* psec */
+#define T_RP		12500	/* psec */
+#define T_RCD		12500	/* psec */
+#define T_RRD		7500	/* psec */
+/* T_RRD_TCK is minimum of 2 clk periods, regardless of freq */
+#define T_RRD_TCK	2
+#define T_WTR		7500	/* psec */
+/* T_WTR_TCK is minimum of 2 clk periods, regardless of freq */
+#define T_WTR_TCK	2
+#define T_RTP		7500	/* psec */
+#define T_RTP_TCK	(BL / 2)
+#define T_XP_TCK	2	/* clocks */
+#define T_CKE_TCK	3	/* clocks */
+#define T_XSNR		(T_RFC_MIN + 10000) /* psec */
+#define T_DLLK		200     /* clocks */
+#define T_RAS_MIN	45000   /* psec */
+#define T_RC		57500   /* psec */
+#define T_FAW		35000   /* psec */
+#define T_MRD_TCK	2       /* clocks */
+#define T_RFI		7800000 /* psec */
+
+/* DDR Addressing */
+#define COL_BITS	10
+#define BA_BITS		3
+#define ROW_BITS	13
+#define CS_BITS		1
+
+/* DDR Addressing scheme: {CS, ROW, BA, COL} */
+#define COL_HI_RSHFT	0
+#define COL_HI_MASK	0
+#define COL_LO_MASK	((1 << COL_BITS) - 1)
+
+#define BA_RSHFT	COL_BITS
+#define BA_MASK		((1 << BA_BITS) - 1)
+
+#define ROW_ADDR_RSHIFT	(BA_RSHFT + BA_BITS)
+#define ROW_ADDR_MASK	((1 << ROW_BITS) - 1)
+
+#define CS_ADDR_RSHIFT	0
+#define CS_ADDR_MASK	0
+
+#endif	/* __MICROCHIP_DDR2_TIMING_H */