/* * TI AEMIF driver * * Copyright (C) 2010 - 2013 Texas Instruments Incorporated. http://www.ti.com/ * * Authors: * Murali Karicheri * Ivan Khoronzhuk * * 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 #include #include #include #include #include #include #include #define TA_SHIFT 2 #define RHOLD_SHIFT 4 #define RSTROBE_SHIFT 7 #define RSETUP_SHIFT 13 #define WHOLD_SHIFT 17 #define WSTROBE_SHIFT 20 #define WSETUP_SHIFT 26 #define EW_SHIFT 30 #define SS_SHIFT 31 #define TA(x) ((x) << TA_SHIFT) #define RHOLD(x) ((x) << RHOLD_SHIFT) #define RSTROBE(x) ((x) << RSTROBE_SHIFT) #define RSETUP(x) ((x) << RSETUP_SHIFT) #define WHOLD(x) ((x) << WHOLD_SHIFT) #define WSTROBE(x) ((x) << WSTROBE_SHIFT) #define WSETUP(x) ((x) << WSETUP_SHIFT) #define EW(x) ((x) << EW_SHIFT) #define SS(x) ((x) << SS_SHIFT) #define ASIZE_MAX 0x1 #define TA_MAX 0x3 #define RHOLD_MAX 0x7 #define RSTROBE_MAX 0x3f #define RSETUP_MAX 0xf #define WHOLD_MAX 0x7 #define WSTROBE_MAX 0x3f #define WSETUP_MAX 0xf #define EW_MAX 0x1 #define SS_MAX 0x1 #define NUM_CS 4 #define TA_VAL(x) (((x) & TA(TA_MAX)) >> TA_SHIFT) #define RHOLD_VAL(x) (((x) & RHOLD(RHOLD_MAX)) >> RHOLD_SHIFT) #define RSTROBE_VAL(x) (((x) & RSTROBE(RSTROBE_MAX)) >> RSTROBE_SHIFT) #define RSETUP_VAL(x) (((x) & RSETUP(RSETUP_MAX)) >> RSETUP_SHIFT) #define WHOLD_VAL(x) (((x) & WHOLD(WHOLD_MAX)) >> WHOLD_SHIFT) #define WSTROBE_VAL(x) (((x) & WSTROBE(WSTROBE_MAX)) >> WSTROBE_SHIFT) #define WSETUP_VAL(x) (((x) & WSETUP(WSETUP_MAX)) >> WSETUP_SHIFT) #define EW_VAL(x) (((x) & EW(EW_MAX)) >> EW_SHIFT) #define SS_VAL(x) (((x) & SS(SS_MAX)) >> SS_SHIFT) #define NRCSR_OFFSET 0x00 #define AWCCR_OFFSET 0x04 #define A1CR_OFFSET 0x10 #define ACR_ASIZE_MASK 0x3 #define ACR_EW_MASK BIT(30) #define ACR_SS_MASK BIT(31) #define ASIZE_16BIT 1 #define CONFIG_MASK (TA(TA_MAX) | \ RHOLD(RHOLD_MAX) | \ RSTROBE(RSTROBE_MAX) | \ RSETUP(RSETUP_MAX) | \ WHOLD(WHOLD_MAX) | \ WSTROBE(WSTROBE_MAX) | \ WSETUP(WSETUP_MAX) | \ EW(EW_MAX) | SS(SS_MAX) | \ ASIZE_MAX) /** * struct aemif_cs_data: structure to hold cs parameters * @cs: chip-select number * @wstrobe: write strobe width, ns * @rstrobe: read strobe width, ns * @wsetup: write setup width, ns * @whold: write hold width, ns * @rsetup: read setup width, ns * @rhold: read hold width, ns * @ta: minimum turn around time, ns * @enable_ss: enable/disable select strobe mode * @enable_ew: enable/disable extended wait mode * @asize: width of the asynchronous device's data bus */ struct aemif_cs_data { u8 cs; u16 wstrobe; u16 rstrobe; u8 wsetup; u8 whold; u8 rsetup; u8 rhold; u8 ta; u8 enable_ss; u8 enable_ew; u8 asize; }; /** * struct aemif_device: structure to hold device data * @base: base address of AEMIF registers * @clk: source clock * @clk_rate: clock's rate in kHz * @num_cs: number of assigned chip-selects * @cs_offset: start number of cs nodes * @cs_data: array of chip-select settings */ struct aemif_device { void __iomem *base; struct clk *clk; unsigned long clk_rate; u8 num_cs; int cs_offset; struct aemif_cs_data cs_data[NUM_CS]; }; /** * aemif_calc_rate - calculate timing data. * @pdev: platform device to calculate for * @wanted: The cycle time needed in nanoseconds. * @clk: The input clock rate in kHz. * @max: The maximum divider value that can be programmed. * * On success, returns the calculated timing value minus 1 for easy * programming into AEMIF timing registers, else negative errno. */ static int aemif_calc_rate(struct platform_device *pdev, int wanted, unsigned long clk, int max) { int result; result = DIV_ROUND_UP((wanted * clk), NSEC_PER_MSEC) - 1; dev_dbg(&pdev->dev, "%s: result %d from %ld, %d\n", __func__, result, clk, wanted); /* It is generally OK to have a more relaxed timing than requested... */ if (result < 0) result = 0; /* ... But configuring tighter timings is not an option. */ else if (result > max) result = -EINVAL; return result; } /** * aemif_config_abus - configure async bus parameters * @pdev: platform device to configure for * @csnum: aemif chip select number * * This function programs the given timing values (in real clock) into the * AEMIF registers taking the AEMIF clock into account. * * This function does not use any locking while programming the AEMIF * because it is expected that there is only one user of a given * chip-select. * * Returns 0 on success, else negative errno. */ static int aemif_config_abus(struct platform_device *pdev, int csnum) { struct aemif_device *aemif = platform_get_drvdata(pdev); struct aemif_cs_data *data = &aemif->cs_data[csnum]; int ta, rhold, rstrobe, rsetup, whold, wstrobe, wsetup; unsigned long clk_rate = aemif->clk_rate; unsigned offset; u32 set, val; offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4; ta = aemif_calc_rate(pdev, data->ta, clk_rate, TA_MAX); rhold = aemif_calc_rate(pdev, data->rhold, clk_rate, RHOLD_MAX); rstrobe = aemif_calc_rate(pdev, data->rstrobe, clk_rate, RSTROBE_MAX); rsetup = aemif_calc_rate(pdev, data->rsetup, clk_rate, RSETUP_MAX); whold = aemif_calc_rate(pdev, data->whold, clk_rate, WHOLD_MAX); wstrobe = aemif_calc_rate(pdev, data->wstrobe, clk_rate, WSTROBE_MAX); wsetup = aemif_calc_rate(pdev, data->wsetup, clk_rate, WSETUP_MAX); if (ta < 0 || rhold < 0 || rstrobe < 0 || rsetup < 0 || whold < 0 || wstrobe < 0 || wsetup < 0) { dev_err(&pdev->dev, "%s: cannot get suitable timings\n", __func__); return -EINVAL; } set = TA(ta) | RHOLD(rhold) | RSTROBE(rstrobe) | RSETUP(rsetup) | WHOLD(whold) | WSTROBE(wstrobe) | WSETUP(wsetup); set |= (data->asize & ACR_ASIZE_MASK); if (data->enable_ew) set |= ACR_EW_MASK; if (data->enable_ss) set |= ACR_SS_MASK; val = readl(aemif->base + offset); val &= ~CONFIG_MASK; val |= set; writel(val, aemif->base + offset); return 0; } static inline int aemif_cycles_to_nsec(int val, unsigned long clk_rate) { return ((val + 1) * NSEC_PER_MSEC) / clk_rate; } /** * aemif_get_hw_params - function to read hw register values * @pdev: platform device to read for * @csnum: aemif chip select number * * This function reads the defaults from the registers and update * the timing values. Required for get/set commands and also for * the case when driver needs to use defaults in hardware. */ static void aemif_get_hw_params(struct platform_device *pdev, int csnum) { struct aemif_device *aemif = platform_get_drvdata(pdev); struct aemif_cs_data *data = &aemif->cs_data[csnum]; unsigned long clk_rate = aemif->clk_rate; u32 val, offset; offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4; val = readl(aemif->base + offset); data->ta = aemif_cycles_to_nsec(TA_VAL(val), clk_rate); data->rhold = aemif_cycles_to_nsec(RHOLD_VAL(val), clk_rate); data->rstrobe = aemif_cycles_to_nsec(RSTROBE_VAL(val), clk_rate); data->rsetup = aemif_cycles_to_nsec(RSETUP_VAL(val), clk_rate); data->whold = aemif_cycles_to_nsec(WHOLD_VAL(val), clk_rate); data->wstrobe = aemif_cycles_to_nsec(WSTROBE_VAL(val), clk_rate); data->wsetup = aemif_cycles_to_nsec(WSETUP_VAL(val), clk_rate); data->enable_ew = EW_VAL(val); data->enable_ss = SS_VAL(val); data->asize = val & ASIZE_MAX; } /** * of_aemif_parse_abus_config - parse CS configuration from DT * @pdev: platform device to parse for * @np: device node ptr * * This function update the emif async bus configuration based on the values * configured in a cs device binding node. */ static int of_aemif_parse_abus_config(struct platform_device *pdev, struct device_node *np) { struct aemif_device *aemif = platform_get_drvdata(pdev); struct aemif_cs_data *data; u32 cs; u32 val; if (of_property_read_u32(np, "ti,cs-chipselect", &cs)) { dev_dbg(&pdev->dev, "cs property is required"); return -EINVAL; } if (cs - aemif->cs_offset >= NUM_CS || cs < aemif->cs_offset) { dev_dbg(&pdev->dev, "cs number is incorrect %d", cs); return -EINVAL; } if (aemif->num_cs >= NUM_CS) { dev_dbg(&pdev->dev, "cs count is more than %d", NUM_CS); return -EINVAL; } data = &aemif->cs_data[aemif->num_cs]; data->cs = cs; /* read the current value in the hw register */ aemif_get_hw_params(pdev, aemif->num_cs++); /* override the values from device node */ if (!of_property_read_u32(np, "ti,cs-min-turnaround-ns", &val)) data->ta = val; if (!of_property_read_u32(np, "ti,cs-read-hold-ns", &val)) data->rhold = val; if (!of_property_read_u32(np, "ti,cs-read-strobe-ns", &val)) data->rstrobe = val; if (!of_property_read_u32(np, "ti,cs-read-setup-ns", &val)) data->rsetup = val; if (!of_property_read_u32(np, "ti,cs-write-hold-ns", &val)) data->whold = val; if (!of_property_read_u32(np, "ti,cs-write-strobe-ns", &val)) data->wstrobe = val; if (!of_property_read_u32(np, "ti,cs-write-setup-ns", &val)) data->wsetup = val; if (!of_property_read_u32(np, "ti,cs-bus-width", &val)) if (val == 16) data->asize = 1; data->enable_ew = of_property_read_bool(np, "ti,cs-extended-wait-mode"); data->enable_ss = of_property_read_bool(np, "ti,cs-select-strobe-mode"); return 0; } static const struct of_device_id aemif_of_match[] = { { .compatible = "ti,davinci-aemif", }, { .compatible = "ti,da850-aemif", }, {}, }; static int aemif_probe(struct platform_device *pdev) { int i; int ret = -ENODEV; struct resource *res; struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; struct device_node *child_np; struct aemif_device *aemif; if (np == NULL) return 0; aemif = devm_kzalloc(dev, sizeof(*aemif), GFP_KERNEL); if (!aemif) return -ENOMEM; platform_set_drvdata(pdev, aemif); aemif->clk = devm_clk_get(dev, NULL); if (IS_ERR(aemif->clk)) { dev_err(dev, "cannot get clock 'aemif'\n"); return PTR_ERR(aemif->clk); } clk_prepare_enable(aemif->clk); aemif->clk_rate = clk_get_rate(aemif->clk) / MSEC_PER_SEC; if (of_device_is_compatible(np, "ti,da850-aemif")) aemif->cs_offset = 2; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); aemif->base = devm_ioremap_resource(dev, res); if (IS_ERR(aemif->base)) { ret = PTR_ERR(aemif->base); goto error; } /* * For every controller device node, there is a cs device node that * describe the bus configuration parameters. This functions iterate * over these nodes and update the cs data array. */ for_each_available_child_of_node(np, child_np) { ret = of_aemif_parse_abus_config(pdev, child_np); if (ret < 0) goto error; } for (i = 0; i < aemif->num_cs; i++) { ret = aemif_config_abus(pdev, i); if (ret < 0) { dev_err(dev, "Error configuring chip select %d\n", aemif->cs_data[i].cs); goto error; } } /* * Create a child devices explicitly from here to * guarantee that the child will be probed after the AEMIF timing * parameters are set. */ for_each_available_child_of_node(np, child_np) { ret = of_platform_populate(child_np, NULL, NULL, dev); if (ret < 0) goto error; } return 0; error: clk_disable_unprepare(aemif->clk); return ret; } static int aemif_remove(struct platform_device *pdev) { struct aemif_device *aemif = platform_get_drvdata(pdev); clk_disable_unprepare(aemif->clk); return 0; } static struct platform_driver aemif_driver = { .probe = aemif_probe, .remove = aemif_remove, .driver = { .name = KBUILD_MODNAME, .of_match_table = of_match_ptr(aemif_of_match), }, }; module_platform_driver(aemif_driver); MODULE_AUTHOR("Murali Karicheri "); MODULE_AUTHOR("Ivan Khoronzhuk "); MODULE_DESCRIPTION("Texas Instruments AEMIF driver"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:" KBUILD_MODNAME);