ARM: S3C24XX: CPUFREQ: S3C2412/S3C2443 IO timing support

Add IO bank timing support for S3C2412/S3C2443.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

1 files changed, 261 insertions, 0 deletions

diff --git a/arch/arm/plat-s3c24xx/s3c2412-iotiming.c b/arch/arm/plat-s3c24xx/s3c2412-iotiming.c
new file mode 100644
index 000000000000..a3648cba0eb9
--- /dev/null
+++ b/arch/arm/plat-s3c24xx/s3c2412-iotiming.c
@@ -0,0 +1,261 @@
+/* linux/arch/arm/plat-s3c24xx/s3c2412-iotiming.c
+ *
+ * Copyright (c) 2006,2008 Simtec Electronics
+ *      http://armlinux.simtec.co.uk/
+ *      Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C2412/S3C2443 (PL093 based) IO timing support
+ *
+ * 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/init.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/cpufreq.h>
+#include <linux/sysdev.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+
+#include <linux/amba/pl093.h>
+
+#include <asm/mach/arch.h>
+#include <asm/mach/map.h>
+
+#include <mach/regs-s3c2412-mem.h>
+
+#include <plat/cpu.h>
+#include <plat/cpu-freq-core.h>
+#include <plat/clock.h>
+
+#define print_ns(x) ((x) / 10), ((x) % 10)
+
+/**
+ * s3c2412_print_timing - print timing infromation via printk.
+ * @pfx: The prefix to print each line with.
+ * @iot: The IO timing information
+ */
+static void s3c2412_print_timing(const char *pfx, struct s3c_iotimings *iot)
+{
+        struct s3c2412_iobank_timing *bt;
+        unsigned int bank;
+
+        for (bank = 0; bank < MAX_BANKS; bank++) {
+                bt = iot->bank[bank].io_2412;
+                if (!bt)
+                        continue;
+
+                printk(KERN_DEBUG "%s: %d: idcy=%d.%d wstrd=%d.%d wstwr=%d,%d"
+                       "wstoen=%d.%d wstwen=%d.%d wstbrd=%d.%d\n", pfx, bank,
+                       print_ns(bt->idcy),
+                       print_ns(bt->wstrd),
+                       print_ns(bt->wstwr),
+                       print_ns(bt->wstoen),
+                       print_ns(bt->wstwen),
+                       print_ns(bt->wstbrd));
+        }
+}
+
+/**
+ * to_div - turn a cycle length into a divisor setting.
+ * @cyc_tns: The cycle time in 10ths of nanoseconds.
+ * @clk_tns: The clock period in 10ths of nanoseconds.
+ */
+static inline unsigned int to_div(unsigned int cyc_tns, unsigned int clk_tns)
+{
+        return cyc_tns ? DIV_ROUND_UP(cyc_tns, clk_tns) : 0;
+}
+
+/**
+ * calc_timing - calculate timing divisor value and check in range.
+ * @hwtm: The hardware timing in 10ths of nanoseconds.
+ * @clk_tns: The clock period in 10ths of nanoseconds.
+ * @err: Pointer to err variable to update in event of failure.
+ */
+static unsigned int calc_timing(unsigned int hwtm, unsigned int clk_tns,
+                                unsigned int *err)
+{
+        unsigned int ret = to_div(hwtm, clk_tns);
+
+        if (ret > 0xf)
+                *err = -EINVAL;
+
+        return ret;
+}
+
+/**
+ * s3c2412_calc_bank - calculate the bank divisor settings.
+ * @cfg: The current frequency configuration.
+ * @bt: The bank timing.
+ */
+static int s3c2412_calc_bank(struct s3c_cpufreq_config *cfg,
+                             struct s3c2412_iobank_timing *bt)
+{
+        unsigned int hclk = cfg->freq.hclk_tns;
+        int err = 0;
+
+        bt->smbidcyr = calc_timing(bt->idcy, hclk, &err);
+        bt->smbwstrd = calc_timing(bt->wstrd, hclk, &err);
+        bt->smbwstwr = calc_timing(bt->wstwr, hclk, &err);
+        bt->smbwstoen = calc_timing(bt->wstoen, hclk, &err);
+        bt->smbwstwen = calc_timing(bt->wstwen, hclk, &err);
+        bt->smbwstbrd = calc_timing(bt->wstbrd, hclk, &err);
+
+        return err;
+}
+
+/**
+ * s3c2412_iotiming_calc - calculate all the bank divisor settings.
+ * @cfg: The current frequency configuration.
+ * @iot: The bank timing information.
+ *
+ * Calculate the timing information for all the banks that are
+ * configured as IO, using s3c2412_calc_bank().
+ */
+int s3c2412_iotiming_calc(struct s3c_cpufreq_config *cfg,
+                          struct s3c_iotimings *iot)
+{
+        struct s3c2412_iobank_timing *bt;
+        int bank;
+        int ret;
+
+        for (bank = 0; bank < MAX_BANKS; bank++) {
+                bt = iot->bank[bank].io_2412;
+                if (!bt)
+                        continue;
+
+                ret = s3c2412_calc_bank(cfg, bt);
+                if (ret) {
+                        printk(KERN_ERR "%s: cannot calculate bank %d io\n",
+                               __func__, bank);
+                        goto err;
+                }
+        }
+
+        return 0;
+ err:
+        return ret;
+}
+
+/**
+ * s3c2412_iotiming_set - set the timing information
+ * @cfg: The current frequency configuration.
+ * @iot: The bank timing information.
+ *
+ * Set the IO bank information from the details calculated earlier from
+ * calling s3c2412_iotiming_calc().
+ */
+void s3c2412_iotiming_set(struct s3c_cpufreq_config *cfg,
+                          struct s3c_iotimings *iot)
+{
+        struct s3c2412_iobank_timing *bt;
+        void __iomem *regs;
+        int bank;
+
+        /* set the io timings from the specifier */
+
+        for (bank = 0; bank < MAX_BANKS; bank++) {
+                bt = iot->bank[bank].io_2412;
+                if (!bt)
+                        continue;
+
+                regs = S3C2412_SSMC_BANK(bank);
+
+                __raw_writel(bt->smbidcyr, regs + SMBIDCYR);
+                __raw_writel(bt->smbwstrd, regs + SMBWSTRDR);
+                __raw_writel(bt->smbwstwr, regs + SMBWSTWRR);
+                __raw_writel(bt->smbwstoen, regs + SMBWSTOENR);
+                __raw_writel(bt->smbwstwen, regs + SMBWSTWENR);
+                __raw_writel(bt->smbwstbrd, regs + SMBWSTBRDR);
+        }
+}
+
+static inline unsigned int s3c2412_decode_timing(unsigned int clock, u32 reg)
+{
+        return (reg & 0xf) * clock;
+}
+
+static void s3c2412_iotiming_getbank(struct s3c_cpufreq_config *cfg,
+                                     struct s3c2412_iobank_timing *bt,
+                                     unsigned int bank)
+{
+        unsigned long clk = cfg->freq.hclk_tns;  /* ssmc clock??? */
+        void __iomem *regs = S3C2412_SSMC_BANK(bank);
+
+        bt->idcy = s3c2412_decode_timing(clk, __raw_readl(regs + SMBIDCYR));
+        bt->wstrd = s3c2412_decode_timing(clk, __raw_readl(regs + SMBWSTRDR));
+        bt->wstoen = s3c2412_decode_timing(clk, __raw_readl(regs + SMBWSTOENR));
+        bt->wstwen = s3c2412_decode_timing(clk, __raw_readl(regs + SMBWSTWENR));
+        bt->wstbrd = s3c2412_decode_timing(clk, __raw_readl(regs + SMBWSTBRDR));
+}
+
+/**
+ * bank_is_io - return true if bank is (possibly) IO.
+ * @bank: The bank number.
+ * @bankcfg: The value of S3C2412_EBI_BANKCFG.
+ */
+static inline bool bank_is_io(unsigned int bank, u32 bankcfg)
+{
+        if (bank < 2)
+                return true;
+
+        return !(bankcfg & (1 << bank));
+}
+
+int s3c2412_iotiming_get(struct s3c_cpufreq_config *cfg,
+                         struct s3c_iotimings *timings)
+{
+        struct s3c2412_iobank_timing *bt;
+        u32 bankcfg = __raw_readl(S3C2412_EBI_BANKCFG);
+        unsigned int bank;
+
+        /* look through all banks to see what is currently set. */
+
+        for (bank = 0; bank < MAX_BANKS; bank++) {
+                if (!bank_is_io(bank, bankcfg))
+                        continue;
+
+                bt = kzalloc(sizeof(struct s3c2412_iobank_timing), GFP_KERNEL);
+                if (!bt) {
+                        printk(KERN_ERR "%s: no memory for bank\n", __func__);
+                        return -ENOMEM;
+                }
+
+                timings->bank[bank].io_2412 = bt;
+                s3c2412_iotiming_getbank(cfg, bt, bank);
+        }
+
+        s3c2412_print_timing("get", timings);
+        return 0;
+}
+
+/* this is in here as it is so small, it doesn't currently warrant a file
+ * to itself. We expect that any s3c24xx needing this is going to also
+ * need the iotiming support.
+ */
+void s3c2412_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
+{
+        struct s3c_cpufreq_board *board = cfg->board;
+        u32 refresh;
+
+        WARN_ON(board == NULL);
+
+        /* Reduce both the refresh time (in ns) and the frequency (in MHz)
+         * down to ensure that we do not overflow 32 bit numbers.
+         *
+         * This should work for HCLK up to 133MHz and refresh period up
+         * to 30usec.
+         */
+
+        refresh = (cfg->freq.hclk / 100) * (board->refresh / 10);
+        refresh = DIV_ROUND_UP(refresh, (1000 * 1000)); /* apply scale  */
+        refresh &= ((1 << 16) - 1);
+
+        s3c_freq_dbg("%s: refresh value %u\n", __func__, (unsigned int)refresh);
+
+        __raw_writel(refresh, S3C2412_REFRESH);
+}