/* * Qualcomm External Bus Interface 2 (EBI2) driver * an older version of the Qualcomm Parallel Interface Controller (QPIC) * * Copyright (C) 2016 Linaro Ltd. * * Author: Linus Walleij <linus.walleij@linaro.org> * * 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. * * See the device tree bindings for this block for more details on the * hardware. */ #include <linux/module.h> #include <linux/clk.h> #include <linux/err.h> #include <linux/io.h> #include <linux/of.h> #include <linux/of_platform.h> #include <linux/init.h> #include <linux/io.h> #include <linux/slab.h> #include <linux/platform_device.h> #include <linux/bitops.h> /* * CS0, CS1, CS4 and CS5 are two bits wide, CS2 and CS3 are one bit. */ #define EBI2_CS0_ENABLE_MASK BIT(0)|BIT(1) #define EBI2_CS1_ENABLE_MASK BIT(2)|BIT(3) #define EBI2_CS2_ENABLE_MASK BIT(4) #define EBI2_CS3_ENABLE_MASK BIT(5) #define EBI2_CS4_ENABLE_MASK BIT(6)|BIT(7) #define EBI2_CS5_ENABLE_MASK BIT(8)|BIT(9) #define EBI2_CSN_MASK GENMASK(9, 0) #define EBI2_XMEM_CFG 0x0000 /* Power management etc */ /* * SLOW CSn CFG * * Bits 31-28: RECOVERY recovery cycles (0 = 1, 1 = 2 etc) this is the time the * memory continues to drive the data bus after OE is de-asserted. * Inserted when reading one CS and switching to another CS or read * followed by write on the same CS. Valid values 0 thru 15. * Bits 27-24: WR_HOLD write hold cycles, these are extra cycles inserted after * every write minimum 1. The data out is driven from the time WE is * asserted until CS is asserted. With a hold of 1, the CS stays * active for 1 extra cycle etc. Valid values 0 thru 15. * Bits 23-16: WR_DELTA initial latency for write cycles inserted for the first * write to a page or burst memory * Bits 15-8: RD_DELTA initial latency for read cycles inserted for the first * read to a page or burst memory * Bits 7-4: WR_WAIT number of wait cycles for every write access, 0=1 cycle * so 1 thru 16 cycles. * Bits 3-0: RD_WAIT number of wait cycles for every read access, 0=1 cycle * so 1 thru 16 cycles. */ #define EBI2_XMEM_CS0_SLOW_CFG 0x0008 #define EBI2_XMEM_CS1_SLOW_CFG 0x000C #define EBI2_XMEM_CS2_SLOW_CFG 0x0010 #define EBI2_XMEM_CS3_SLOW_CFG 0x0014 #define EBI2_XMEM_CS4_SLOW_CFG 0x0018 #define EBI2_XMEM_CS5_SLOW_CFG 0x001C #define EBI2_XMEM_RECOVERY_SHIFT 28 #define EBI2_XMEM_WR_HOLD_SHIFT 24 #define EBI2_XMEM_WR_DELTA_SHIFT 16 #define EBI2_XMEM_RD_DELTA_SHIFT 8 #define EBI2_XMEM_WR_WAIT_SHIFT 4 #define EBI2_XMEM_RD_WAIT_SHIFT 0 /* * FAST CSn CFG * Bits 31-28: ? * Bits 27-24: RD_HOLD: the length in cycles of the first segment of a read * transfer. For a single read trandfer this will be the time * from CS assertion to OE assertion. * Bits 18-24: ? * Bits 17-16: ADV_OE_RECOVERY, the number of cycles elapsed before an OE * assertion, with respect to the cycle where ADV is asserted. * 2 means 2 cycles between ADV and OE. Values 0, 1, 2 or 3. * Bits 5: ADDR_HOLD_ENA, The address is held for an extra cycle to meet * hold time requirements with ADV assertion. * * The manual mentions "write precharge cycles" and "precharge cycles". * We have not been able to figure out which bit fields these correspond to * in the hardware, or what valid values exist. The current hypothesis is that * this is something just used on the FAST chip selects. There is also a "byte * device enable" flag somewhere for 8bit memories. */ #define EBI2_XMEM_CS0_FAST_CFG 0x0028 #define EBI2_XMEM_CS1_FAST_CFG 0x002C #define EBI2_XMEM_CS2_FAST_CFG 0x0030 #define EBI2_XMEM_CS3_FAST_CFG 0x0034 #define EBI2_XMEM_CS4_FAST_CFG 0x0038 #define EBI2_XMEM_CS5_FAST_CFG 0x003C #define EBI2_XMEM_RD_HOLD_SHIFT 24 #define EBI2_XMEM_ADV_OE_RECOVERY_SHIFT 16 #define EBI2_XMEM_ADDR_HOLD_ENA_SHIFT 5 /** * struct cs_data - struct with info on a chipselect setting * @enable_mask: mask to enable the chipselect in the EBI2 config * @slow_cfg0: offset to XMEMC slow CS config * @fast_cfg1: offset to XMEMC fast CS config */ struct cs_data { u32 enable_mask; u16 slow_cfg; u16 fast_cfg; }; static const struct cs_data cs_info[] = { { /* CS0 */ .enable_mask = EBI2_CS0_ENABLE_MASK, .slow_cfg = EBI2_XMEM_CS0_SLOW_CFG, .fast_cfg = EBI2_XMEM_CS0_FAST_CFG, }, { /* CS1 */ .enable_mask = EBI2_CS1_ENABLE_MASK, .slow_cfg = EBI2_XMEM_CS1_SLOW_CFG, .fast_cfg = EBI2_XMEM_CS1_FAST_CFG, }, { /* CS2 */ .enable_mask = EBI2_CS2_ENABLE_MASK, .slow_cfg = EBI2_XMEM_CS2_SLOW_CFG, .fast_cfg = EBI2_XMEM_CS2_FAST_CFG, }, { /* CS3 */ .enable_mask = EBI2_CS3_ENABLE_MASK, .slow_cfg = EBI2_XMEM_CS3_SLOW_CFG, .fast_cfg = EBI2_XMEM_CS3_FAST_CFG, }, { /* CS4 */ .enable_mask = EBI2_CS4_ENABLE_MASK, .slow_cfg = EBI2_XMEM_CS4_SLOW_CFG, .fast_cfg = EBI2_XMEM_CS4_FAST_CFG, }, { /* CS5 */ .enable_mask = EBI2_CS5_ENABLE_MASK, .slow_cfg = EBI2_XMEM_CS5_SLOW_CFG, .fast_cfg = EBI2_XMEM_CS5_FAST_CFG, }, }; /** * struct ebi2_xmem_prop - describes an XMEM config property * @prop: the device tree binding name * @max: maximum value for the property * @slowreg: true if this property is in the SLOW CS config register * else it is assumed to be in the FAST config register * @shift: the bit field start in the SLOW or FAST register for this * property */ struct ebi2_xmem_prop { const char *prop; u32 max; bool slowreg; u16 shift; }; static const struct ebi2_xmem_prop xmem_props[] = { { .prop = "qcom,xmem-recovery-cycles", .max = 15, .slowreg = true, .shift = EBI2_XMEM_RECOVERY_SHIFT, }, { .prop = "qcom,xmem-write-hold-cycles", .max = 15, .slowreg = true, .shift = EBI2_XMEM_WR_HOLD_SHIFT, }, { .prop = "qcom,xmem-write-delta-cycles", .max = 255, .slowreg = true, .shift = EBI2_XMEM_WR_DELTA_SHIFT, }, { .prop = "qcom,xmem-read-delta-cycles", .max = 255, .slowreg = true, .shift = EBI2_XMEM_RD_DELTA_SHIFT, }, { .prop = "qcom,xmem-write-wait-cycles", .max = 15, .slowreg = true, .shift = EBI2_XMEM_WR_WAIT_SHIFT, }, { .prop = "qcom,xmem-read-wait-cycles", .max = 15, .slowreg = true, .shift = EBI2_XMEM_RD_WAIT_SHIFT, }, { .prop = "qcom,xmem-address-hold-enable", .max = 1, /* boolean prop */ .slowreg = false, .shift = EBI2_XMEM_ADDR_HOLD_ENA_SHIFT, }, { .prop = "qcom,xmem-adv-to-oe-recovery-cycles", .max = 3, .slowreg = false, .shift = EBI2_XMEM_ADV_OE_RECOVERY_SHIFT, }, { .prop = "qcom,xmem-read-hold-cycles", .max = 15, .slowreg = false, .shift = EBI2_XMEM_RD_HOLD_SHIFT, }, }; static void qcom_ebi2_setup_chipselect(struct device_node *np, struct device *dev, void __iomem *ebi2_base, void __iomem *ebi2_xmem, u32 csindex) { const struct cs_data *csd; u32 slowcfg, fastcfg; u32 val; int ret; int i; csd = &cs_info[csindex]; val = readl(ebi2_base); val |= csd->enable_mask; writel(val, ebi2_base); dev_dbg(dev, "enabled CS%u\n", csindex); /* Next set up the XMEMC */ slowcfg = 0; fastcfg = 0; for (i = 0; i < ARRAY_SIZE(xmem_props); i++) { const struct ebi2_xmem_prop *xp = &xmem_props[i]; /* All are regular u32 values */ ret = of_property_read_u32(np, xp->prop, &val); if (ret) { dev_dbg(dev, "could not read %s for CS%d\n", xp->prop, csindex); continue; } /* First check boolean props */ if (xp->max == 1 && val) { if (xp->slowreg) slowcfg |= BIT(xp->shift); else fastcfg |= BIT(xp->shift); dev_dbg(dev, "set %s flag\n", xp->prop); continue; } /* We're dealing with an u32 */ if (val > xp->max) { dev_err(dev, "too high value for %s: %u, capped at %u\n", xp->prop, val, xp->max); val = xp->max; } if (xp->slowreg) slowcfg |= (val << xp->shift); else fastcfg |= (val << xp->shift); dev_dbg(dev, "set %s to %u\n", xp->prop, val); } dev_info(dev, "CS%u: SLOW CFG 0x%08x, FAST CFG 0x%08x\n", csindex, slowcfg, fastcfg); if (slowcfg) writel(slowcfg, ebi2_xmem + csd->slow_cfg); if (fastcfg) writel(fastcfg, ebi2_xmem + csd->fast_cfg); } static int qcom_ebi2_probe(struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; struct device_node *child; struct device *dev = &pdev->dev; struct resource *res; void __iomem *ebi2_base; void __iomem *ebi2_xmem; struct clk *ebi2xclk; struct clk *ebi2clk; bool have_children = false; u32 val; int ret; ebi2xclk = devm_clk_get(dev, "ebi2x"); if (IS_ERR(ebi2xclk)) return PTR_ERR(ebi2xclk); ret = clk_prepare_enable(ebi2xclk); if (ret) { dev_err(dev, "could not enable EBI2X clk (%d)\n", ret); return ret; } ebi2clk = devm_clk_get(dev, "ebi2"); if (IS_ERR(ebi2clk)) { ret = PTR_ERR(ebi2clk); goto err_disable_2x_clk; } ret = clk_prepare_enable(ebi2clk); if (ret) { dev_err(dev, "could not enable EBI2 clk\n"); goto err_disable_2x_clk; } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); ebi2_base = devm_ioremap_resource(dev, res); if (IS_ERR(ebi2_base)) { ret = PTR_ERR(ebi2_base); goto err_disable_clk; } res = platform_get_resource(pdev, IORESOURCE_MEM, 1); ebi2_xmem = devm_ioremap_resource(dev, res); if (IS_ERR(ebi2_xmem)) { ret = PTR_ERR(ebi2_xmem); goto err_disable_clk; } /* Allegedly this turns the power save mode off */ writel(0UL, ebi2_xmem + EBI2_XMEM_CFG); /* Disable all chipselects */ val = readl(ebi2_base); val &= ~EBI2_CSN_MASK; writel(val, ebi2_base); /* Walk over the child nodes and see what chipselects we use */ for_each_available_child_of_node(np, child) { u32 csindex; /* Figure out the chipselect */ ret = of_property_read_u32(child, "reg", &csindex); if (ret) return ret; if (csindex > 5) { dev_err(dev, "invalid chipselect %u, we only support 0-5\n", csindex); continue; } qcom_ebi2_setup_chipselect(child, dev, ebi2_base, ebi2_xmem, csindex); /* We have at least one child */ have_children = true; } if (have_children) return of_platform_default_populate(np, NULL, dev); return 0; err_disable_clk: clk_disable_unprepare(ebi2clk); err_disable_2x_clk: clk_disable_unprepare(ebi2xclk); return ret; } static const struct of_device_id qcom_ebi2_of_match[] = { { .compatible = "qcom,msm8660-ebi2", }, { .compatible = "qcom,apq8060-ebi2", }, { } }; static struct platform_driver qcom_ebi2_driver = { .probe = qcom_ebi2_probe, .driver = { .name = "qcom-ebi2", .of_match_table = qcom_ebi2_of_match, }, }; module_platform_driver(qcom_ebi2_driver); MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>"); MODULE_DESCRIPTION("Qualcomm EBI2 driver"); MODULE_LICENSE("GPL");