FSL DDR: Rewrite the FSL mpc8xxx DDR controller setup code.

The main purpose of this rewrite it to be able to share the same
initialization code on all FSL PowerPC products that have DDR
controllers.  (83xx, 85xx, 86xx).

The code is broken up into the following steps:
	GET_SPD
	COMPUTE_DIMM_PARMS
	COMPUTE_COMMON_PARMS
	GATHER_OPTS
	ASSIGN_ADDRESSES
	COMPUTE_REGS
	PROGRAM_REGS

This allows us to share more code an easily allow for board specific code
overrides.

Additionally this code base adds support for >4G of DDR and provides a
foundation for supporting interleaving on processors with more than one
controller.

Signed-off-by: James Yang <James.Yang@freescale.com>
Signed-off-by: Jon Loeliger <jdl@freescale.com>
Signed-off-by: Becky Bruce <becky.bruce@freescale.com>
Signed-off-by: Ed Swarthout <Ed.Swarthout@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

1 files changed, 404 insertions, 0 deletions

diff --git a/cpu/mpc8xxx/ddr/lc_common_dimm_params.c b/cpu/mpc8xxx/ddr/lc_common_dimm_params.c
new file mode 100644
index 00000000000..fbeb236d952
--- /dev/null
+++ b/cpu/mpc8xxx/ddr/lc_common_dimm_params.c
@@ -0,0 +1,404 @@
+/*
+ * Copyright 2008 Freescale Semiconductor, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * Version 2 as published by the Free Software Foundation.
+ */
+
+#include <common.h>
+#include <asm/fsl_ddr_sdram.h>
+
+#include "ddr.h"
+
+/*
+ * compute_lowest_common_dimm_parameters()
+ *
+ * Determine the worst-case DIMM timing parameters from the set of DIMMs
+ * whose parameters have been computed into the array pointed to
+ * by dimm_params.
+ */
+unsigned int
+compute_lowest_common_dimm_parameters(const dimm_params_t *dimm_params,
+				      common_timing_params_t *outpdimm,
+				      unsigned int number_of_dimms)
+{
+	unsigned int i;
+
+	unsigned int tCKmin_X_ps = 0;
+	unsigned int tCKmax_ps = 0xFFFFFFFF;
+	unsigned int tCKmax_max_ps = 0;
+	unsigned int tRCD_ps = 0;
+	unsigned int tRP_ps = 0;
+	unsigned int tRAS_ps = 0;
+	unsigned int tWR_ps = 0;
+	unsigned int tWTR_ps = 0;
+	unsigned int tRFC_ps = 0;
+	unsigned int tRRD_ps = 0;
+	unsigned int tRC_ps = 0;
+	unsigned int refresh_rate_ps = 0;
+	unsigned int tIS_ps = 0;
+	unsigned int tIH_ps = 0;
+	unsigned int tDS_ps = 0;
+	unsigned int tDH_ps = 0;
+	unsigned int tRTP_ps = 0;
+	unsigned int tDQSQ_max_ps = 0;
+	unsigned int tQHS_ps = 0;
+
+	unsigned int temp1, temp2;
+	unsigned int lowest_good_caslat;
+	unsigned int additive_latency = 0;
+	const unsigned int mclk_ps = get_memory_clk_period_ps();
+	unsigned int not_ok;
+
+	debug("using mclk_ps = %u\n", mclk_ps);
+
+	temp1 = 0;
+	for (i = 0; i < number_of_dimms; i++) {
+		/*
+		 * If there are no ranks on this DIMM,
+		 * it probably doesn't exist, so skip it.
+		 */
+		if (dimm_params[i].n_ranks == 0) {
+			temp1++;
+			continue;
+		}
+
+		/*
+		 * Find minimum tCKmax_ps to find fastest slow speed,
+		 * i.e., this is the slowest the whole system can go.
+		 */
+		tCKmax_ps = min(tCKmax_ps, dimm_params[i].tCKmax_ps);
+
+		/* Either find maximum value to determine slowest
+		 * speed, delay, time, period, etc */
+		tCKmin_X_ps = max(tCKmin_X_ps, dimm_params[i].tCKmin_X_ps);
+		tCKmax_max_ps = max(tCKmax_max_ps, dimm_params[i].tCKmax_ps);
+		tRCD_ps = max(tRCD_ps, dimm_params[i].tRCD_ps);
+		tRP_ps = max(tRP_ps, dimm_params[i].tRP_ps);
+		tRAS_ps = max(tRAS_ps, dimm_params[i].tRAS_ps);
+		tWR_ps = max(tWR_ps, dimm_params[i].tWR_ps);
+		tWTR_ps = max(tWTR_ps, dimm_params[i].tWTR_ps);
+		tRFC_ps = max(tRFC_ps, dimm_params[i].tRFC_ps);
+		tRRD_ps = max(tRRD_ps, dimm_params[i].tRRD_ps);
+		tRC_ps = max(tRC_ps, dimm_params[i].tRC_ps);
+		tIS_ps = max(tIS_ps, dimm_params[i].tIS_ps);
+		tIH_ps = max(tIH_ps, dimm_params[i].tIH_ps);
+		tDS_ps = max(tDS_ps, dimm_params[i].tDS_ps);
+		tDH_ps = max(tDH_ps, dimm_params[i].tDH_ps);
+		tRTP_ps = max(tRTP_ps, dimm_params[i].tRTP_ps);
+		tQHS_ps = max(tQHS_ps, dimm_params[i].tQHS_ps);
+		refresh_rate_ps = max(refresh_rate_ps,
+				      dimm_params[i].refresh_rate_ps);
+
+		/*
+		 * Find maximum tDQSQ_max_ps to find slowest.
+		 *
+		 * FIXME: is finding the slowest value the correct
+		 * strategy for this parameter?
+		 */
+		tDQSQ_max_ps = max(tDQSQ_max_ps, dimm_params[i].tDQSQ_max_ps);
+	}
+
+	outpdimm->ndimms_present = number_of_dimms - temp1;
+
+	if (temp1 == number_of_dimms) {
+		debug("no dimms this memory controller\n");
+		return 0;
+	}
+
+	outpdimm->tCKmin_X_ps = tCKmin_X_ps;
+	outpdimm->tCKmax_ps = tCKmax_ps;
+	outpdimm->tCKmax_max_ps = tCKmax_max_ps;
+	outpdimm->tRCD_ps = tRCD_ps;
+	outpdimm->tRP_ps = tRP_ps;
+	outpdimm->tRAS_ps = tRAS_ps;
+	outpdimm->tWR_ps = tWR_ps;
+	outpdimm->tWTR_ps = tWTR_ps;
+	outpdimm->tRFC_ps = tRFC_ps;
+	outpdimm->tRRD_ps = tRRD_ps;
+	outpdimm->tRC_ps = tRC_ps;
+	outpdimm->refresh_rate_ps = refresh_rate_ps;
+	outpdimm->tIS_ps = tIS_ps;
+	outpdimm->tIH_ps = tIH_ps;
+	outpdimm->tDS_ps = tDS_ps;
+	outpdimm->tDH_ps = tDH_ps;
+	outpdimm->tRTP_ps = tRTP_ps;
+	outpdimm->tDQSQ_max_ps = tDQSQ_max_ps;
+	outpdimm->tQHS_ps = tQHS_ps;
+
+	/* Determine common burst length for all DIMMs. */
+	temp1 = 0xff;
+	for (i = 0; i < number_of_dimms; i++) {
+		if (dimm_params[i].n_ranks) {
+			temp1 &= dimm_params[i].burst_lengths_bitmask;
+		}
+	}
+	outpdimm->all_DIMMs_burst_lengths_bitmask = temp1;
+
+	/* Determine if all DIMMs registered buffered. */
+	temp1 = temp2 = 0;
+	for (i = 0; i < number_of_dimms; i++) {
+		if (dimm_params[i].n_ranks) {
+			if (dimm_params[i].registered_dimm)
+				temp1 = 1;
+			if (!dimm_params[i].registered_dimm)
+				temp2 = 1;
+		}
+	}
+
+	outpdimm->all_DIMMs_registered = 0;
+	if (temp1 && !temp2) {
+		outpdimm->all_DIMMs_registered = 1;
+	}
+
+	outpdimm->all_DIMMs_unbuffered = 0;
+	if (!temp1 && temp2) {
+		outpdimm->all_DIMMs_unbuffered = 1;
+	}
+
+	/* CHECKME: */
+	if (!outpdimm->all_DIMMs_registered
+	    && !outpdimm->all_DIMMs_unbuffered) {
+		printf("ERROR:  Mix of registered buffered and unbuffered "
+				"DIMMs detected!\n");
+	}
+
+	/*
+	 * Compute a CAS latency suitable for all DIMMs
+	 *
+	 * Strategy for SPD-defined latencies: compute only
+	 * CAS latency defined by all DIMMs.
+	 */
+
+	/*
+	 * Step 1: find CAS latency common to all DIMMs using bitwise
+	 * operation.
+	 */
+	temp1 = 0xFF;
+	for (i = 0; i < number_of_dimms; i++) {
+		if (dimm_params[i].n_ranks) {
+			temp2 = 0;
+			temp2 |= 1 << dimm_params[i].caslat_X;
+			temp2 |= 1 << dimm_params[i].caslat_X_minus_1;
+			temp2 |= 1 << dimm_params[i].caslat_X_minus_2;
+			/*
+			 * FIXME: If there was no entry for X-2 (X-1) in
+			 * the SPD, then caslat_X_minus_2
+			 * (caslat_X_minus_1) contains either 255 or
+			 * 0xFFFFFFFF because that's what the glorious
+			 * __ilog2 function returns for an input of 0.
+			 * On 32-bit PowerPC, left shift counts with bit
+			 * 26 set (that the value of 255 or 0xFFFFFFFF
+			 * will have), cause the destination register to
+			 * be 0.  That is why this works.
+			 */
+			temp1 &= temp2;
+		}
+	}
+
+	/*
+	 * Step 2: check each common CAS latency against tCK of each
+	 * DIMM's SPD.
+	 */
+	lowest_good_caslat = 0;
+	temp2 = 0;
+	while (temp1) {
+		not_ok = 0;
+		temp2 =  __ilog2(temp1);
+		debug("checking common caslat = %u\n", temp2);
+
+		/* Check if this CAS latency will work on all DIMMs at tCK. */
+		for (i = 0; i < number_of_dimms; i++) {
+			if (!dimm_params[i].n_ranks) {
+				continue;
+			}
+			if (dimm_params[i].caslat_X == temp2) {
+				if (mclk_ps >= dimm_params[i].tCKmin_X_ps) {
+					debug("CL = %u ok on DIMM %u at tCK=%u"
+					    " ps with its tCKmin_X_ps of %u\n",
+					       temp2, i, mclk_ps,
+					       dimm_params[i].tCKmin_X_ps);
+					continue;
+				} else {
+					not_ok++;
+				}
+			}
+
+			if (dimm_params[i].caslat_X_minus_1 == temp2) {
+				unsigned int tCKmin_X_minus_1_ps
+					= dimm_params[i].tCKmin_X_minus_1_ps;
+				if (mclk_ps >= tCKmin_X_minus_1_ps) {
+					debug("CL = %u ok on DIMM %u at "
+						"tCK=%u ps with its "
+						"tCKmin_X_minus_1_ps of %u\n",
+					       temp2, i, mclk_ps,
+					       tCKmin_X_minus_1_ps);
+					continue;
+				} else {
+					not_ok++;
+				}
+			}
+
+			if (dimm_params[i].caslat_X_minus_2 == temp2) {
+				unsigned int tCKmin_X_minus_2_ps
+					= dimm_params[i].tCKmin_X_minus_2_ps;
+				if (mclk_ps >= tCKmin_X_minus_2_ps) {
+					debug("CL = %u ok on DIMM %u at "
+						"tCK=%u ps with its "
+						"tCKmin_X_minus_2_ps of %u\n",
+					       temp2, i, mclk_ps,
+					       tCKmin_X_minus_2_ps);
+					continue;
+				} else {
+					not_ok++;
+				}
+			}
+		}
+
+		if (!not_ok) {
+			lowest_good_caslat = temp2;
+		}
+
+		temp1 &= ~(1 << temp2);
+	}
+
+	debug("lowest common SPD-defined CAS latency = %u\n",
+	       lowest_good_caslat);
+	outpdimm->lowest_common_SPD_caslat = lowest_good_caslat;
+
+
+	/*
+	 * Compute a common 'de-rated' CAS latency.
+	 *
+	 * The strategy here is to find the *highest* dereated cas latency
+	 * with the assumption that all of the DIMMs will support a dereated
+	 * CAS latency higher than or equal to their lowest dereated value.
+	 */
+	temp1 = 0;
+	for (i = 0; i < number_of_dimms; i++) {
+		temp1 = max(temp1, dimm_params[i].caslat_lowest_derated);
+	}
+	outpdimm->highest_common_derated_caslat = temp1;
+	debug("highest common dereated CAS latency = %u\n", temp1);
+
+	/* Determine if all DIMMs ECC capable. */
+	temp1 = 1;
+	for (i = 0; i < number_of_dimms; i++) {
+		if (dimm_params[i].n_ranks && dimm_params[i].edc_config != 2) {
+			temp1 = 0;
+			break;
+		}
+	}
+	if (temp1) {
+		debug("all DIMMs ECC capable\n");
+	} else {
+		debug("Warning: not all DIMMs ECC capable, cant enable ECC\n");
+	}
+	outpdimm->all_DIMMs_ECC_capable = temp1;
+
+
+	/* FIXME: move to somewhere else to validate. */
+	if (mclk_ps > tCKmax_max_ps) {
+		printf("Warning: some of the installed DIMMs "
+				"can not operate this slowly.\n");
+		return 1;
+	}
+
+	/*
+	 * Compute additive latency.
+	 *
+	 * For DDR1, additive latency should be 0.
+	 *
+	 * For DDR2, with ODT enabled, use "a value" less than ACTTORW,
+	 *	which comes from Trcd, and also note that:
+	 *	    add_lat + caslat must be >= 4
+	 *
+	 * For DDR3, FIXME additive latency determination
+	 *
+	 * When to use additive latency for DDR2:
+	 *
+	 * I. Because you are using CL=3 and need to do ODT on writes and
+	 *    want functionality.
+	 *    1. Are you going to use ODT? (Does your board not have
+	 *      additional termination circuitry for DQ, DQS, DQS_,
+	 *      DM, RDQS, RDQS_ for x4/x8 configs?)
+	 *    2. If so, is your lowest supported CL going to be 3?
+	 *    3. If so, then you must set AL=1 because
+	 *
+	 *       WL >= 3 for ODT on writes
+	 *       RL = AL + CL
+	 *       WL = RL - 1
+	 *       ->
+	 *       WL = AL + CL - 1
+	 *       AL + CL - 1 >= 3
+	 *       AL + CL >= 4
+	 *  QED
+	 *
+	 *  RL >= 3 for ODT on reads
+	 *  RL = AL + CL
+	 *
+	 *  Since CL aren't usually less than 2, AL=0 is a minimum,
+	 *  so the WL-derived AL should be the  -- FIXME?
+	 *
+	 * II. Because you are using auto-precharge globally and want to
+	 *     use additive latency (posted CAS) to get more bandwidth.
+	 *     1. Are you going to use auto-precharge mode globally?
+	 *
+	 *        Use addtivie latency and compute AL to be 1 cycle less than
+	 *        tRCD, i.e. the READ or WRITE command is in the cycle
+	 *        immediately following the ACTIVATE command..
+	 *
+	 * III. Because you feel like it or want to do some sort of
+	 *      degraded-performance experiment.
+	 *     1.  Do you just want to use additive latency because you feel
+	 *         like it?
+	 *
+	 * Validation:  AL is less than tRCD, and within the other
+	 * read-to-precharge constraints.
+	 */
+
+	additive_latency = 0;
+
+#if defined(CONFIG_FSL_DDR2)
+	if (lowest_good_caslat < 4) {
+		additive_latency = picos_to_mclk(tRCD_ps) - lowest_good_caslat;
+		if (mclk_to_picos(additive_latency) > tRCD_ps) {
+			additive_latency = picos_to_mclk(tRCD_ps);
+			debug("setting additive_latency to %u because it was "
+				" greater than tRCD_ps\n", additive_latency);
+		}
+	}
+
+#elif defined(CONFIG_FSL_DDR3)
+error "FIXME determine additive latency for DDR3"
+#endif
+
+	/*
+	 * Validate additive latency
+	 * FIXME: move to somewhere else to validate
+	 *
+	 * AL <= tRCD(min)
+	 */
+	if (mclk_to_picos(additive_latency) > tRCD_ps) {
+		printf("Error: invalid additive latency exceeds tRCD(min).\n");
+		return 1;
+	}
+
+	/*
+	 * RL = CL + AL;  RL >= 3 for ODT_RD_CFG to be enabled
+	 * WL = RL - 1;  WL >= 3 for ODT_WL_CFG to be enabled
+	 * ADD_LAT (the register) must be set to a value less
+	 * than ACTTORW if WL = 1, then AL must be set to 1
+	 * RD_TO_PRE (the register) must be set to a minimum
+	 * tRTP + AL if AL is nonzero
+	 */
+
+	/*
+	 * Additive latency will be applied only if the memctl option to
+	 * use it.
+	 */
+	outpdimm->additive_latency = additive_latency;
+
+	return 0;
+}