arch/c6x/platforms/emif.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  External Memory Interface
   4  *
   5  *  Copyright (C) 2011 Texas Instruments Incorporated
   6  *  Author: Mark Salter <msalter@redhat.com>
   7  */
   8 #include <linux/of.h>
   9 #include <linux/of_address.h>
  10 #include <linux/io.h>
  11 #include <asm/soc.h>
  12 #include <asm/dscr.h>
  13
  14 #define NUM_EMIFA_CHIP_ENABLES 4
  15
  16 struct emifa_regs {
  17         u32     midr;
  18         u32     stat;
  19         u32     reserved1[6];
  20         u32     bprio;
  21         u32     reserved2[23];
  22         u32     cecfg[NUM_EMIFA_CHIP_ENABLES];
  23         u32     reserved3[4];
  24         u32     awcc;
  25         u32     reserved4[7];
  26         u32     intraw;
  27         u32     intmsk;
  28         u32     intmskset;
  29         u32     intmskclr;
  30 };
  31
  32 static struct of_device_id emifa_match[] __initdata = {
  33         { .compatible = "ti,c64x+emifa" },
  34         {}
  35 };
  36
  37 /*
  38  * Parse device tree for existence of an EMIF (External Memory Interface)
  39  * and initialize it if found.
  40  */
  41 static int __init c6x_emifa_init(void)
  42 {
  43         struct emifa_regs __iomem *regs;
  44         struct device_node *node;
  45         const __be32 *p;
  46         u32 val;
  47         int i, len, err;
  48
  49         node = of_find_matching_node(NULL, emifa_match);
  50         if (!node)
  51                 return 0;
  52
  53         regs = of_iomap(node, 0);
  54         if (!regs)
  55                 return 0;
  56
  57         /* look for a dscr-based enable for emifa pin buffers */
  58         err = of_property_read_u32_array(node, "ti,dscr-dev-enable", &val, 1);
  59         if (!err)
  60                 dscr_set_devstate(val, DSCR_DEVSTATE_ENABLED);
  61
  62         /* set up the chip enables */
  63         p = of_get_property(node, "ti,emifa-ce-config", &len);
  64         if (p) {
  65                 len /= sizeof(u32);
  66                 if (len > NUM_EMIFA_CHIP_ENABLES)
  67                         len = NUM_EMIFA_CHIP_ENABLES;
  68                 for (i = 0; i <= len; i++)
  69                         soc_writel(be32_to_cpup(&p[i]), &regs->cecfg[i]);
  70         }
  71
  72         err = of_property_read_u32_array(node, "ti,emifa-burst-priority", &val, 1);
  73         if (!err)
  74                 soc_writel(val, &regs->bprio);
  75
  76         err = of_property_read_u32_array(node, "ti,emifa-async-wait-control", &val, 1);
  77         if (!err)
  78                 soc_writel(val, &regs->awcc);
  79
  80         iounmap(regs);
  81         of_node_put(node);
  82         return 0;
  83 }
  84 pure_initcall(c6x_emifa_init);