davinci: Support various speedgrades for MityDSP-L138 and MityARM-1808 SoMs

For the MityDSP-L138/MityARM-1808 SoMs, the speed grade can be determined
from the part number string read from the factory configuration block on
the on-board I2C PROM.  Configure the maximum CPU speed based on this
information.

This patch was tested using a MityDSP-L138 and MityARM-1808 at various
speedgrades.  Also, for code coverage, a bogus configuration was tested
as well as a configuration having an unknown part number.

Signed-off-by: Michael Williamson <michael.williamson@criticallink.com>
Tested-by: Michael Williamson <michael.williamson@criticallink.com>
Reviewed-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

diff --git a/arch/arm/mach-davinci/board-mityomapl138.c b/arch/arm/mach-davinci/board-mityomapl138.c
index 0bb5f0ce4fdcea69b38eb2d16673613f3a463de2..0ea59327dc28a80d567ebbbf3fd1540bb920ebfe 100644 (file)
--- a/arch/arm/mach-davinci/board-mityomapl138.c
+++ b/arch/arm/mach-davinci/board-mityomapl138.c
@@ -44,38 +44,109 @@ struct factory_config {
 
 static struct factory_config factory_config;
 
+struct part_no_info {
+       const char      *part_no;       /* part number string of interest */
+       int             max_freq;       /* khz */
+};
+
+static struct part_no_info mityomapl138_pn_info[] = {
+       {
+               .part_no        = "L138-C",
+               .max_freq       = 300000,
+       },
+       {
+               .part_no        = "L138-D",
+               .max_freq       = 375000,
+       },
+       {
+               .part_no        = "L138-F",
+               .max_freq       = 456000,
+       },
+       {
+               .part_no        = "1808-C",
+               .max_freq       = 300000,
+       },
+       {
+               .part_no        = "1808-D",
+               .max_freq       = 375000,
+       },
+       {
+               .part_no        = "1808-F",
+               .max_freq       = 456000,
+       },
+       {
+               .part_no        = "1810-D",
+               .max_freq       = 375000,
+       },
+};
+
+#ifdef CONFIG_CPU_FREQ
+static void mityomapl138_cpufreq_init(const char *partnum)
+{
+       int i, ret;
+
+       for (i = 0; partnum && i < ARRAY_SIZE(mityomapl138_pn_info); i++) {
+               /*
+                * the part number has additional characters beyond what is
+                * stored in the table.  This information is not needed for
+                * determining the speed grade, and would require several
+                * more table entries.  Only check the first N characters
+                * for a match.
+                */
+               if (!strncmp(partnum, mityomapl138_pn_info[i].part_no,
+                            strlen(mityomapl138_pn_info[i].part_no))) {
+                       da850_max_speed = mityomapl138_pn_info[i].max_freq;
+                       break;
+               }
+       }
+
+       ret = da850_register_cpufreq("pll0_sysclk3");
+       if (ret)
+               pr_warning("cpufreq registration failed: %d\n", ret);
+}
+#else
+static void mityomapl138_cpufreq_init(const char *partnum) { }
+#endif
+
 static void read_factory_config(struct memory_accessor *a, void *context)
 {
        int ret;
+       const char *partnum = NULL;
        struct davinci_soc_info *soc_info = &davinci_soc_info;
 
        ret = a->read(a, (char *)&factory_config, 0, sizeof(factory_config));
        if (ret != sizeof(struct factory_config)) {
                pr_warning("MityOMAPL138: Read Factory Config Failed: %d\n",
                                ret);
-               return;
+               goto bad_config;
        }
 
        if (factory_config.magic != FACTORY_CONFIG_MAGIC) {
                pr_warning("MityOMAPL138: Factory Config Magic Wrong (%X)\n",
                                factory_config.magic);
-               return;
+               goto bad_config;
        }
 
        if (factory_config.version != FACTORY_CONFIG_VERSION) {
                pr_warning("MityOMAPL138: Factory Config Version Wrong (%X)\n",
                                factory_config.version);
-               return;
+               goto bad_config;
        }
 
        pr_info("MityOMAPL138: Found MAC = %pM\n", factory_config.mac);
-       pr_info("MityOMAPL138: Part Number = %s\n", factory_config.partnum);
        if (is_valid_ether_addr(factory_config.mac))
                memcpy(soc_info->emac_pdata->mac_addr,
                        factory_config.mac, ETH_ALEN);
        else
                pr_warning("MityOMAPL138: Invalid MAC found "
                                "in factory config block\n");
+
+       partnum = factory_config.partnum;
+       pr_info("MityOMAPL138: Part Number = %s\n", partnum);
+
+bad_config:
+       /* default maximum speed is valid for all platforms */
+       mityomapl138_cpufreq_init(partnum);
 }
 
 static struct at24_platform_data mityomapl138_fd_chip = {
@@ -383,10 +454,6 @@ static void __init mityomapl138_init(void)
        if (ret)
                pr_warning("rtc setup failed: %d\n", ret);
 
-       ret = da850_register_cpufreq("pll0_sysclk3");
-       if (ret)
-               pr_warning("cpufreq registration failed: %d\n", ret);
-
        ret = da8xx_register_cpuidle();
        if (ret)
                pr_warning("cpuidle registration failed: %d\n", ret);