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-rw-r--r--arch/arm/mach-davinci/aemif.c218
1 files changed, 218 insertions, 0 deletions
diff --git a/arch/arm/mach-davinci/aemif.c b/arch/arm/mach-davinci/aemif.c
new file mode 100644
index 000000000..ff8b7e76b
--- /dev/null
+++ b/arch/arm/mach-davinci/aemif.c
@@ -0,0 +1,218 @@
+/*
+ * AEMIF support for DaVinci SoCs
+ *
+ * Copyright (C) 2010 Texas Instruments Incorporated. http://www.ti.com/
+ *
+ * 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 <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/time.h>
+
+#include <linux/platform_data/mtd-davinci-aemif.h>
+#include <linux/platform_data/mtd-davinci.h>
+
+/* Timing value configuration */
+
+#define TA(x) ((x) << 2)
+#define RHOLD(x) ((x) << 4)
+#define RSTROBE(x) ((x) << 7)
+#define RSETUP(x) ((x) << 13)
+#define WHOLD(x) ((x) << 17)
+#define WSTROBE(x) ((x) << 20)
+#define WSETUP(x) ((x) << 26)
+
+#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 TIMING_MASK (TA(TA_MAX) | \
+ RHOLD(RHOLD_MAX) | \
+ RSTROBE(RSTROBE_MAX) | \
+ RSETUP(RSETUP_MAX) | \
+ WHOLD(WHOLD_MAX) | \
+ WSTROBE(WSTROBE_MAX) | \
+ WSETUP(WSETUP_MAX))
+
+static inline unsigned int davinci_aemif_readl(void __iomem *base, int offset)
+{
+ return readl_relaxed(base + offset);
+}
+
+static inline void davinci_aemif_writel(void __iomem *base,
+ int offset, unsigned long value)
+{
+ writel_relaxed(value, base + offset);
+}
+
+/*
+ * aemif_calc_rate - calculate timing data.
+ * @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(int wanted, unsigned long clk, int max)
+{
+ int result;
+
+ result = DIV_ROUND_UP((wanted * clk), NSEC_PER_MSEC) - 1;
+
+ pr_debug("%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;
+}
+
+/**
+ * davinci_aemif_setup_timing - setup timing values for a given AEMIF interface
+ * @t: timing values to be progammed
+ * @base: The virtual base address of the AEMIF interface
+ * @cs: chip-select to program the timing values for
+ * @clkrate: the AEMIF clkrate
+ *
+ * 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 davinci_aemif_setup_timing(struct davinci_aemif_timing *t,
+ void __iomem *base, unsigned cs,
+ unsigned long clkrate)
+{
+ unsigned set, val;
+ int ta, rhold, rstrobe, rsetup, whold, wstrobe, wsetup;
+ unsigned offset = A1CR_OFFSET + cs * 4;
+
+ if (!t)
+ return 0; /* Nothing to do */
+
+ clkrate /= 1000; /* turn clock into kHz for ease of use */
+
+ ta = aemif_calc_rate(t->ta, clkrate, TA_MAX);
+ rhold = aemif_calc_rate(t->rhold, clkrate, RHOLD_MAX);
+ rstrobe = aemif_calc_rate(t->rstrobe, clkrate, RSTROBE_MAX);
+ rsetup = aemif_calc_rate(t->rsetup, clkrate, RSETUP_MAX);
+ whold = aemif_calc_rate(t->whold, clkrate, WHOLD_MAX);
+ wstrobe = aemif_calc_rate(t->wstrobe, clkrate, WSTROBE_MAX);
+ wsetup = aemif_calc_rate(t->wsetup, clkrate, WSETUP_MAX);
+
+ if (ta < 0 || rhold < 0 || rstrobe < 0 || rsetup < 0 ||
+ whold < 0 || wstrobe < 0 || wsetup < 0) {
+ pr_err("%s: cannot get suitable timings\n", __func__);
+ return -EINVAL;
+ }
+
+ set = TA(ta) | RHOLD(rhold) | RSTROBE(rstrobe) | RSETUP(rsetup) |
+ WHOLD(whold) | WSTROBE(wstrobe) | WSETUP(wsetup);
+
+ val = __raw_readl(base + offset);
+ val &= ~TIMING_MASK;
+ val |= set;
+ __raw_writel(val, base + offset);
+
+ return 0;
+}
+
+/**
+ * davinci_aemif_setup - setup AEMIF interface by davinci_nand_pdata
+ * @pdev - link to platform device to setup settings for
+ *
+ * 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.
+ */
+int davinci_aemif_setup(struct platform_device *pdev)
+{
+ struct davinci_nand_pdata *pdata = dev_get_platdata(&pdev->dev);
+ uint32_t val;
+ unsigned long clkrate;
+ struct resource *res;
+ void __iomem *base;
+ struct clk *clk;
+ int ret = 0;
+
+ clk = clk_get(&pdev->dev, "aemif");
+ if (IS_ERR(clk)) {
+ ret = PTR_ERR(clk);
+ dev_dbg(&pdev->dev, "unable to get AEMIF clock, err %d\n", ret);
+ return ret;
+ }
+
+ ret = clk_prepare_enable(clk);
+ if (ret < 0) {
+ dev_dbg(&pdev->dev, "unable to enable AEMIF clock, err %d\n",
+ ret);
+ goto err_put;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+ if (!res) {
+ dev_err(&pdev->dev, "cannot get IORESOURCE_MEM\n");
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ base = ioremap(res->start, resource_size(res));
+ if (!base) {
+ dev_err(&pdev->dev, "ioremap failed for resource %pR\n", res);
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ /*
+ * Setup Async configuration register in case we did not boot
+ * from NAND and so bootloader did not bother to set it up.
+ */
+ val = davinci_aemif_readl(base, A1CR_OFFSET + pdev->id * 4);
+ /*
+ * Extended Wait is not valid and Select Strobe mode is not
+ * used
+ */
+ val &= ~(ACR_ASIZE_MASK | ACR_EW_MASK | ACR_SS_MASK);
+ if (pdata->options & NAND_BUSWIDTH_16)
+ val |= 0x1;
+
+ davinci_aemif_writel(base, A1CR_OFFSET + pdev->id * 4, val);
+
+ clkrate = clk_get_rate(clk);
+
+ if (pdata->timing)
+ ret = davinci_aemif_setup_timing(pdata->timing, base, pdev->id,
+ clkrate);
+
+ if (ret < 0)
+ dev_dbg(&pdev->dev, "NAND timing values setup fail\n");
+
+ iounmap(base);
+err:
+ clk_disable_unprepare(clk);
+err_put:
+ clk_put(clk);
+ return ret;
+}