406 lines
10 KiB
C
406 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Qualcomm External Bus Interface 2 (EBI2) driver
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* an older version of the Qualcomm Parallel Interface Controller (QPIC)
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*
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* Copyright (C) 2016 Linaro Ltd.
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*
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* Author: Linus Walleij <linus.walleij@linaro.org>
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*
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* See the device tree bindings for this block for more details on the
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* hardware.
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*/
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#include <linux/module.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/platform_device.h>
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#include <linux/bitops.h>
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/*
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* CS0, CS1, CS4 and CS5 are two bits wide, CS2 and CS3 are one bit.
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*/
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#define EBI2_CS0_ENABLE_MASK BIT(0)|BIT(1)
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#define EBI2_CS1_ENABLE_MASK BIT(2)|BIT(3)
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#define EBI2_CS2_ENABLE_MASK BIT(4)
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#define EBI2_CS3_ENABLE_MASK BIT(5)
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#define EBI2_CS4_ENABLE_MASK BIT(6)|BIT(7)
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#define EBI2_CS5_ENABLE_MASK BIT(8)|BIT(9)
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#define EBI2_CSN_MASK GENMASK(9, 0)
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#define EBI2_XMEM_CFG 0x0000 /* Power management etc */
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/*
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* SLOW CSn CFG
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*
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* Bits 31-28: RECOVERY recovery cycles (0 = 1, 1 = 2 etc) this is the time the
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* memory continues to drive the data bus after OE is de-asserted.
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* Inserted when reading one CS and switching to another CS or read
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* followed by write on the same CS. Valid values 0 thru 15.
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* Bits 27-24: WR_HOLD write hold cycles, these are extra cycles inserted after
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* every write minimum 1. The data out is driven from the time WE is
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* asserted until CS is asserted. With a hold of 1, the CS stays
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* active for 1 extra cycle etc. Valid values 0 thru 15.
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* Bits 23-16: WR_DELTA initial latency for write cycles inserted for the first
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* write to a page or burst memory
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* Bits 15-8: RD_DELTA initial latency for read cycles inserted for the first
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* read to a page or burst memory
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* Bits 7-4: WR_WAIT number of wait cycles for every write access, 0=1 cycle
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* so 1 thru 16 cycles.
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* Bits 3-0: RD_WAIT number of wait cycles for every read access, 0=1 cycle
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* so 1 thru 16 cycles.
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*/
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#define EBI2_XMEM_CS0_SLOW_CFG 0x0008
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#define EBI2_XMEM_CS1_SLOW_CFG 0x000C
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#define EBI2_XMEM_CS2_SLOW_CFG 0x0010
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#define EBI2_XMEM_CS3_SLOW_CFG 0x0014
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#define EBI2_XMEM_CS4_SLOW_CFG 0x0018
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#define EBI2_XMEM_CS5_SLOW_CFG 0x001C
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#define EBI2_XMEM_RECOVERY_SHIFT 28
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#define EBI2_XMEM_WR_HOLD_SHIFT 24
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#define EBI2_XMEM_WR_DELTA_SHIFT 16
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#define EBI2_XMEM_RD_DELTA_SHIFT 8
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#define EBI2_XMEM_WR_WAIT_SHIFT 4
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#define EBI2_XMEM_RD_WAIT_SHIFT 0
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/*
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* FAST CSn CFG
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* Bits 31-28: ?
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* Bits 27-24: RD_HOLD: the length in cycles of the first segment of a read
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* transfer. For a single read trandfer this will be the time
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* from CS assertion to OE assertion.
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* Bits 18-24: ?
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* Bits 17-16: ADV_OE_RECOVERY, the number of cycles elapsed before an OE
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* assertion, with respect to the cycle where ADV is asserted.
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* 2 means 2 cycles between ADV and OE. Values 0, 1, 2 or 3.
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* Bits 5: ADDR_HOLD_ENA, The address is held for an extra cycle to meet
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* hold time requirements with ADV assertion.
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*
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* The manual mentions "write precharge cycles" and "precharge cycles".
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* We have not been able to figure out which bit fields these correspond to
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* in the hardware, or what valid values exist. The current hypothesis is that
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* this is something just used on the FAST chip selects. There is also a "byte
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* device enable" flag somewhere for 8bit memories.
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*/
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#define EBI2_XMEM_CS0_FAST_CFG 0x0028
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#define EBI2_XMEM_CS1_FAST_CFG 0x002C
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#define EBI2_XMEM_CS2_FAST_CFG 0x0030
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#define EBI2_XMEM_CS3_FAST_CFG 0x0034
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#define EBI2_XMEM_CS4_FAST_CFG 0x0038
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#define EBI2_XMEM_CS5_FAST_CFG 0x003C
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#define EBI2_XMEM_RD_HOLD_SHIFT 24
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#define EBI2_XMEM_ADV_OE_RECOVERY_SHIFT 16
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#define EBI2_XMEM_ADDR_HOLD_ENA_SHIFT 5
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/**
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* struct cs_data - struct with info on a chipselect setting
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* @enable_mask: mask to enable the chipselect in the EBI2 config
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* @slow_cfg: offset to XMEMC slow CS config
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* @fast_cfg: offset to XMEMC fast CS config
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*/
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struct cs_data {
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u32 enable_mask;
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u16 slow_cfg;
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u16 fast_cfg;
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};
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static const struct cs_data cs_info[] = {
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{
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/* CS0 */
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.enable_mask = EBI2_CS0_ENABLE_MASK,
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.slow_cfg = EBI2_XMEM_CS0_SLOW_CFG,
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.fast_cfg = EBI2_XMEM_CS0_FAST_CFG,
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},
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{
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/* CS1 */
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.enable_mask = EBI2_CS1_ENABLE_MASK,
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.slow_cfg = EBI2_XMEM_CS1_SLOW_CFG,
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.fast_cfg = EBI2_XMEM_CS1_FAST_CFG,
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},
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{
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/* CS2 */
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.enable_mask = EBI2_CS2_ENABLE_MASK,
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.slow_cfg = EBI2_XMEM_CS2_SLOW_CFG,
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.fast_cfg = EBI2_XMEM_CS2_FAST_CFG,
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},
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{
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/* CS3 */
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.enable_mask = EBI2_CS3_ENABLE_MASK,
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.slow_cfg = EBI2_XMEM_CS3_SLOW_CFG,
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.fast_cfg = EBI2_XMEM_CS3_FAST_CFG,
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},
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{
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/* CS4 */
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.enable_mask = EBI2_CS4_ENABLE_MASK,
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.slow_cfg = EBI2_XMEM_CS4_SLOW_CFG,
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.fast_cfg = EBI2_XMEM_CS4_FAST_CFG,
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},
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{
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/* CS5 */
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.enable_mask = EBI2_CS5_ENABLE_MASK,
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.slow_cfg = EBI2_XMEM_CS5_SLOW_CFG,
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.fast_cfg = EBI2_XMEM_CS5_FAST_CFG,
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},
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};
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/**
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* struct ebi2_xmem_prop - describes an XMEM config property
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* @prop: the device tree binding name
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* @max: maximum value for the property
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* @slowreg: true if this property is in the SLOW CS config register
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* else it is assumed to be in the FAST config register
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* @shift: the bit field start in the SLOW or FAST register for this
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* property
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*/
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struct ebi2_xmem_prop {
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const char *prop;
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u32 max;
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bool slowreg;
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u16 shift;
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};
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static const struct ebi2_xmem_prop xmem_props[] = {
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{
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.prop = "qcom,xmem-recovery-cycles",
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.max = 15,
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.slowreg = true,
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.shift = EBI2_XMEM_RECOVERY_SHIFT,
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},
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{
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.prop = "qcom,xmem-write-hold-cycles",
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.max = 15,
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.slowreg = true,
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.shift = EBI2_XMEM_WR_HOLD_SHIFT,
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},
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{
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.prop = "qcom,xmem-write-delta-cycles",
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.max = 255,
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.slowreg = true,
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.shift = EBI2_XMEM_WR_DELTA_SHIFT,
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},
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{
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.prop = "qcom,xmem-read-delta-cycles",
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.max = 255,
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.slowreg = true,
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.shift = EBI2_XMEM_RD_DELTA_SHIFT,
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},
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{
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.prop = "qcom,xmem-write-wait-cycles",
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.max = 15,
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.slowreg = true,
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.shift = EBI2_XMEM_WR_WAIT_SHIFT,
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},
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{
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.prop = "qcom,xmem-read-wait-cycles",
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.max = 15,
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.slowreg = true,
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.shift = EBI2_XMEM_RD_WAIT_SHIFT,
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},
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{
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.prop = "qcom,xmem-address-hold-enable",
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.max = 1, /* boolean prop */
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.slowreg = false,
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.shift = EBI2_XMEM_ADDR_HOLD_ENA_SHIFT,
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},
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{
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.prop = "qcom,xmem-adv-to-oe-recovery-cycles",
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.max = 3,
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.slowreg = false,
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.shift = EBI2_XMEM_ADV_OE_RECOVERY_SHIFT,
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},
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{
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.prop = "qcom,xmem-read-hold-cycles",
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.max = 15,
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.slowreg = false,
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.shift = EBI2_XMEM_RD_HOLD_SHIFT,
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},
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};
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static void qcom_ebi2_setup_chipselect(struct device_node *np,
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struct device *dev,
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void __iomem *ebi2_base,
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void __iomem *ebi2_xmem,
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u32 csindex)
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{
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const struct cs_data *csd;
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u32 slowcfg, fastcfg;
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u32 val;
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int ret;
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int i;
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csd = &cs_info[csindex];
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val = readl(ebi2_base);
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val |= csd->enable_mask;
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writel(val, ebi2_base);
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dev_dbg(dev, "enabled CS%u\n", csindex);
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/* Next set up the XMEMC */
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slowcfg = 0;
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fastcfg = 0;
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for (i = 0; i < ARRAY_SIZE(xmem_props); i++) {
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const struct ebi2_xmem_prop *xp = &xmem_props[i];
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/* All are regular u32 values */
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ret = of_property_read_u32(np, xp->prop, &val);
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if (ret) {
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dev_dbg(dev, "could not read %s for CS%d\n",
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xp->prop, csindex);
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continue;
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}
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/* First check boolean props */
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if (xp->max == 1 && val) {
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if (xp->slowreg)
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slowcfg |= BIT(xp->shift);
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else
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fastcfg |= BIT(xp->shift);
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dev_dbg(dev, "set %s flag\n", xp->prop);
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continue;
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}
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/* We're dealing with an u32 */
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if (val > xp->max) {
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dev_err(dev,
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"too high value for %s: %u, capped at %u\n",
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xp->prop, val, xp->max);
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val = xp->max;
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}
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if (xp->slowreg)
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slowcfg |= (val << xp->shift);
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else
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fastcfg |= (val << xp->shift);
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dev_dbg(dev, "set %s to %u\n", xp->prop, val);
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}
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dev_info(dev, "CS%u: SLOW CFG 0x%08x, FAST CFG 0x%08x\n",
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csindex, slowcfg, fastcfg);
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if (slowcfg)
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writel(slowcfg, ebi2_xmem + csd->slow_cfg);
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if (fastcfg)
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writel(fastcfg, ebi2_xmem + csd->fast_cfg);
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}
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static int qcom_ebi2_probe(struct platform_device *pdev)
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{
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struct device_node *np = pdev->dev.of_node;
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struct device_node *child;
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struct device *dev = &pdev->dev;
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struct resource *res;
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void __iomem *ebi2_base;
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void __iomem *ebi2_xmem;
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struct clk *ebi2xclk;
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struct clk *ebi2clk;
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bool have_children = false;
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u32 val;
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int ret;
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ebi2xclk = devm_clk_get(dev, "ebi2x");
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if (IS_ERR(ebi2xclk))
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return PTR_ERR(ebi2xclk);
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ret = clk_prepare_enable(ebi2xclk);
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if (ret) {
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dev_err(dev, "could not enable EBI2X clk (%d)\n", ret);
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return ret;
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}
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ebi2clk = devm_clk_get(dev, "ebi2");
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if (IS_ERR(ebi2clk)) {
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ret = PTR_ERR(ebi2clk);
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goto err_disable_2x_clk;
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}
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ret = clk_prepare_enable(ebi2clk);
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if (ret) {
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dev_err(dev, "could not enable EBI2 clk\n");
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goto err_disable_2x_clk;
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}
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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ebi2_base = devm_ioremap_resource(dev, res);
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if (IS_ERR(ebi2_base)) {
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ret = PTR_ERR(ebi2_base);
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goto err_disable_clk;
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}
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res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
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ebi2_xmem = devm_ioremap_resource(dev, res);
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if (IS_ERR(ebi2_xmem)) {
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ret = PTR_ERR(ebi2_xmem);
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goto err_disable_clk;
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}
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/* Allegedly this turns the power save mode off */
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writel(0UL, ebi2_xmem + EBI2_XMEM_CFG);
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/* Disable all chipselects */
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val = readl(ebi2_base);
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val &= ~EBI2_CSN_MASK;
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writel(val, ebi2_base);
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/* Walk over the child nodes and see what chipselects we use */
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for_each_available_child_of_node(np, child) {
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u32 csindex;
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/* Figure out the chipselect */
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ret = of_property_read_u32(child, "reg", &csindex);
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if (ret) {
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of_node_put(child);
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return ret;
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}
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if (csindex > 5) {
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dev_err(dev,
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"invalid chipselect %u, we only support 0-5\n",
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csindex);
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continue;
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}
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qcom_ebi2_setup_chipselect(child,
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dev,
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ebi2_base,
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ebi2_xmem,
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csindex);
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/* We have at least one child */
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have_children = true;
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}
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if (have_children)
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return of_platform_default_populate(np, NULL, dev);
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return 0;
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err_disable_clk:
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clk_disable_unprepare(ebi2clk);
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err_disable_2x_clk:
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clk_disable_unprepare(ebi2xclk);
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return ret;
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}
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static const struct of_device_id qcom_ebi2_of_match[] = {
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{ .compatible = "qcom,msm8660-ebi2", },
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{ .compatible = "qcom,apq8060-ebi2", },
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{ }
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};
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static struct platform_driver qcom_ebi2_driver = {
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.probe = qcom_ebi2_probe,
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.driver = {
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.name = "qcom-ebi2",
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.of_match_table = qcom_ebi2_of_match,
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},
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};
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module_platform_driver(qcom_ebi2_driver);
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MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
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MODULE_DESCRIPTION("Qualcomm EBI2 driver");
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