diff options
Diffstat (limited to 'arch/arm/cpu/tegra20-common/emc.c')
-rw-r--r-- | arch/arm/cpu/tegra20-common/emc.c | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/arch/arm/cpu/tegra20-common/emc.c b/arch/arm/cpu/tegra20-common/emc.c new file mode 100644 index 0000000000..ffc05e453a --- /dev/null +++ b/arch/arm/cpu/tegra20-common/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/tegra20.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; +} |