ENGR00306955-1 ARM:imx6x Ensure that both IRAM and OCRAM_S can be mapped in the IRAM page table

To prevent a page table walk in the DDR, its required that the low
power code use a minimal set of page tables that are stored in IRAM.
This IRAM page table needs to have a known virtual address so the
mapping needs to be created at the beginning of boot using iotable_init().
This patch fixes the following issues:
1. Ensure that OCRAM_S, IRAM, AIPS1 and AIPS2 can all be mapped by the
IMX_IO_P2V macro.
2. Ensure Section mapping is used for the required addresses in the IRAM
page table.
3. Obtain the address of the IRAM/OCRAM_S to be used by low power code
from the device tree. Since the device tree is not setup early in the boot,
use the flat device tree apis to get the address.

Signed-off-by: Ranjani Vaidyanathan <Ranjani.Vaidyanathan@freescale.com>

2 files changed, 71 insertions, 38 deletions

diff --git a/arch/arm/mach-imx/hardware.h b/arch/arm/mach-imx/hardware.h
index 89dc771baadf..378fa846bf99 100644
--- a/arch/arm/mach-imx/hardware.h
+++ b/arch/arm/mach-imx/hardware.h
@@ -89,27 +89,21 @@
  *      AIPS1   0x53f00000+0x100000     ->      0xf5700000+0x100000
  *      AIPS2   0x63f00000+0x100000     ->      0xf5300000+0x100000
  * mx6q:
- *      SCU     0x00a00000+0x004000     ->      0xf4000000+0x004000
+ *      OCRAMS  0x008f8000+0x004000     ->      0xf48f8000+0x004000
+ *      IRAM    0x00900000+0x040000     ->      0xf4900000+0x040000
+ *      SCU     0x00a00000+0x004000     ->      0xf4a00000+0x004000
+ *      AIPS1   0x02000000+0x100000     ->      0xf4200000+0x100000
+ *      AIPS2   0x02100000+0x100000     ->      0xf4300000+0x100000
  *      CCM     0x020c4000+0x004000     ->      0xf42c4000+0x004000
  *      ANATOP  0x020c8000+0x004000     ->      0xf42c8000+0x004000
- *      UART4   0x021f0000+0x004000     ->      0xf42f0000+0x004000
+ *      UART4   0x021f0000+0x004000     ->      0xf43f0000+0x004000
  */
- #if defined(CONFIG_SOC_IMX6Q) || defined(CONFIG_SOC_IMX6SL)
 #define IMX_IO_P2V(x)   (                                               \
-                        (((x) & 0x80000000) >> 7) |                     \
                         (0xf4000000 +                                   \
-                        (((x) & 0x50000000) >> 6) +                     \
-                        (((x) & 0x0b000000) >> 4) +                     \
-                        (((x) & 0x00100000) << 5) +                     \
-                        (((x) & 0x000fffff))))
-#else
-#define IMX_IO_P2V(x)   (                                               \
-                        (((x) & 0x80000000) >> 7) |                     \
-                        (0xf4000000 +                                   \
-                        (((x) & 0x50000000) >> 6) +                     \
-                        (((x) & 0x0b000000) >> 4) +                     \
-                        (((x) & 0x000fffff))))
-#endif
+                        (((x) & 0x50000000) >> 4) +                     \
+                        (((x) & 0x0a000000) >> 4) +                     \
+                        (((x) & 0x00ffffff))))
+
 
 #define IMX_IO_ADDRESS(x)       IOMEM(IMX_IO_P2V(x))
 
diff --git a/arch/arm/mach-imx/pm-imx6.c b/arch/arm/mach-imx/pm-imx6.c
index 50a231fecd36..91c7ec39dc49 100644
--- a/arch/arm/mach-imx/pm-imx6.c
+++ b/arch/arm/mach-imx/pm-imx6.c
@@ -15,6 +15,7 @@
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_fdt.h>
 #include <linux/of_irq.h>
 #include <linux/suspend.h>
 #include <linux/genalloc.h>
@@ -265,6 +266,12 @@ static int imx6_pm_enter(suspend_state_t state)
 {
         struct regmap *g;
 
+        if (!iram_tlb_base_addr) {
+                pr_warn("No IRAM/OCRAM memory allocated for suspend/resume code. \
+                        Please ensure device tree has an entry for fsl,lpm-sram.\n");
+                        return -EINVAL;
+        }
+
         /*
          * L2 can exit by 'reset' or Inband beacon (from remote EP)
          * toggling phy_powerdown has same effect as 'inband beacon'
@@ -356,6 +363,36 @@ static struct map_desc iram_tlb_io_desc __initdata = {
         .type           = MT_MEMORY_NONCACHED,
 };
 
+const static char *low_power_ocram_match[] __initconst = {
+        "fsl,lpm-sram",
+        NULL
+};
+
+static int __init imx6_dt_find_lpsram(unsigned long node,
+                const char *uname, int depth, void *data)
+{
+        unsigned long lpram_addr;
+        __be32 *prop;
+
+        if (of_flat_dt_match(node, low_power_ocram_match)) {
+                prop = of_get_flat_dt_prop(node, "reg", NULL);
+                if (!prop)
+                        return -EINVAL;
+
+                lpram_addr = be32_to_cpup(prop);
+
+                /* We need to create a 1M page table entry. */
+                iram_tlb_io_desc.virtual = IMX_IO_P2V(lpram_addr & 0xFFF00000);
+                iram_tlb_io_desc.pfn = __phys_to_pfn(lpram_addr & 0xFFF00000);
+                iram_tlb_phys_addr = lpram_addr;
+                iram_tlb_base_addr = IMX_IO_P2V(lpram_addr);
+
+                iotable_init(&iram_tlb_io_desc, 1);
+        }
+        return 0;
+
+}
+
 void __init imx6_pm_map_io(void)
 {
         unsigned long i;
@@ -363,21 +400,14 @@ void __init imx6_pm_map_io(void)
         iotable_init(imx6_pm_io_desc, ARRAY_SIZE(imx6_pm_io_desc));
 
         /*
-         * Allocate IRAM for page tables to be used
-         * when DDR is in self-refresh.
+         * Get the address of IRAM or OCRAM to be used by the low
+         * power code from the device tree.
          */
-        if (cpu_is_imx6sx()) {
-                iram_tlb_io_desc.virtual = IMX_IO_P2V(MX6SX_IRAM_TLB_BASE_ADDR);
-                iram_tlb_io_desc.pfn = __phys_to_pfn(MX6SX_IRAM_TLB_BASE_ADDR);
-                iram_tlb_phys_addr = MX6SX_IRAM_TLB_BASE_ADDR;
-                iram_tlb_base_addr = IMX_IO_P2V(MX6SX_IRAM_TLB_BASE_ADDR);
-        } else {
-                iram_tlb_io_desc.virtual = IMX_IO_P2V(MX6Q_IRAM_TLB_BASE_ADDR);
-                iram_tlb_io_desc.pfn = __phys_to_pfn(MX6Q_IRAM_TLB_BASE_ADDR);
-                iram_tlb_phys_addr = MX6Q_IRAM_TLB_BASE_ADDR;
-                iram_tlb_base_addr = IMX_IO_P2V(MX6Q_IRAM_TLB_BASE_ADDR);
-        }
-        iotable_init(&iram_tlb_io_desc, 1);
+        WARN_ON(of_scan_flat_dt(imx6_dt_find_lpsram, NULL));
+
+        /* Return if no IRAM space is allocated for suspend/resume code. */
+        if (!iram_tlb_base_addr)
+                return;
 
         /* Set all entries to 0. */
         memset((void *)iram_tlb_base_addr, 0, SZ_16K);
@@ -385,31 +415,34 @@ void __init imx6_pm_map_io(void)
         /*
          * Make sure the IRAM virtual address has a mapping
          * in the IRAM page table.
+         * Only use the top 11 bits [31-20] when storing the
+         * physical address in the page table as only these
+         * bits are required for 1M mapping.
          */
-        i = (iram_tlb_base_addr >> 18) / 4;
+        i = ((iram_tlb_base_addr >> 20) << 2) / 4;
         *((unsigned long *)iram_tlb_base_addr + i) =
-                iram_tlb_phys_addr | TT_ATTRIB_NON_CACHEABLE_1M;
+                (iram_tlb_phys_addr & 0xFFF00000) | TT_ATTRIB_NON_CACHEABLE_1M;
         /*
          * Make sure the AIPS1 virtual address has a mapping
          * in the IRAM page table.
          */
-        i = (IMX_IO_P2V(MX6Q_AIPS1_BASE_ADDR) >> 18) / 4;
+        i = ((IMX_IO_P2V(MX6Q_AIPS1_BASE_ADDR) >> 20) << 2) / 4;
         *((unsigned long *)iram_tlb_base_addr + i) =
-                MX6Q_AIPS1_BASE_ADDR | TT_ATTRIB_NON_CACHEABLE_1M;
+                (MX6Q_AIPS1_BASE_ADDR  & 0xFFF00000) | TT_ATTRIB_NON_CACHEABLE_1M;
         /*
         * Make sure the AIPS2 virtual address has a mapping
         * in the IRAM page table.
         */
-        i = (IMX_IO_P2V(MX6Q_AIPS2_BASE_ADDR) >> 18) / 4;
+        i = ((IMX_IO_P2V(MX6Q_AIPS2_BASE_ADDR) >> 20) << 2) / 4;
         *((unsigned long *)iram_tlb_base_addr + i) =
-                MX6Q_AIPS2_BASE_ADDR | TT_ATTRIB_NON_CACHEABLE_1M;
+                (MX6Q_AIPS2_BASE_ADDR  & 0xFFF00000) | TT_ATTRIB_NON_CACHEABLE_1M;
         /*
          * Make sure the AIPS2 virtual address has a mapping
          * in the IRAM page table.
          */
-        i = (IMX_IO_P2V(MX6Q_L2_BASE_ADDR) >> 18) / 4;
+        i = ((IMX_IO_P2V(MX6Q_L2_BASE_ADDR) >> 20) << 2) / 4;
         *((unsigned long *)iram_tlb_base_addr + i) =
-                MX6Q_L2_BASE_ADDR | TT_ATTRIB_NON_CACHEABLE_1M;
+                (MX6Q_L2_BASE_ADDR  & 0xFFF00000) | TT_ATTRIB_NON_CACHEABLE_1M;
 
 }
 
@@ -432,6 +465,12 @@ void imx6_pm_set_ccm_base(void __iomem *base)
 
 void __init imx6_pm_init(void)
 {
+        if (!iram_tlb_base_addr) {
+                pr_warn("No IRAM/OCRAM memory allocated for suspend/resume code. \
+Please ensure device tree has an entry fsl,lpm-sram\n");
+                        return;
+        }
+
         iram_paddr = iram_tlb_phys_addr + MX6_SUSPEND_IRAM_ADDR_OFFSET;
         /* Get the virtual address of the suspend code. */
         suspend_iram_base = (void *)IMX_IO_P2V(iram_tlb_phys_addr) +