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Diffstat (limited to 'drivers/soc/bcm/brcmstb/pm/pm-arm.c')
-rw-r--r--drivers/soc/bcm/brcmstb/pm/pm-arm.c874
1 files changed, 874 insertions, 0 deletions
diff --git a/drivers/soc/bcm/brcmstb/pm/pm-arm.c b/drivers/soc/bcm/brcmstb/pm/pm-arm.c
new file mode 100644
index 000000000..d681cd24c
--- /dev/null
+++ b/drivers/soc/bcm/brcmstb/pm/pm-arm.c
@@ -0,0 +1,874 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ARM-specific support for Broadcom STB S2/S3/S5 power management
+ *
+ * S2: clock gate CPUs and as many peripherals as possible
+ * S3: power off all of the chip except the Always ON (AON) island; keep DDR is
+ * self-refresh
+ * S5: (a.k.a. S3 cold boot) much like S3, except DDR is powered down, so we
+ * treat this mode like a soft power-off, with wakeup allowed from AON
+ *
+ * Copyright © 2014-2017 Broadcom
+ */
+
+#define pr_fmt(fmt) "brcmstb-pm: " fmt
+
+#include <linux/bitops.h>
+#include <linux/compiler.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/kconfig.h>
+#include <linux/kernel.h>
+#include <linux/memblock.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/panic_notifier.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/printk.h>
+#include <linux/proc_fs.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+#include <linux/suspend.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/soc/brcmstb/brcmstb.h>
+
+#include <asm/fncpy.h>
+#include <asm/setup.h>
+#include <asm/suspend.h>
+
+#include "pm.h"
+#include "aon_defs.h"
+
+#define SHIMPHY_DDR_PAD_CNTRL 0x8c
+
+/* Method #0 */
+#define SHIMPHY_PAD_PLL_SEQUENCE BIT(8)
+#define SHIMPHY_PAD_GATE_PLL_S3 BIT(9)
+
+/* Method #1 */
+#define PWRDWN_SEQ_NO_SEQUENCING 0
+#define PWRDWN_SEQ_HOLD_CHANNEL 1
+#define PWRDWN_SEQ_RESET_PLL 2
+#define PWRDWN_SEQ_POWERDOWN_PLL 3
+
+#define SHIMPHY_PAD_S3_PWRDWN_SEQ_MASK 0x00f00000
+#define SHIMPHY_PAD_S3_PWRDWN_SEQ_SHIFT 20
+
+#define DDR_FORCE_CKE_RST_N BIT(3)
+#define DDR_PHY_RST_N BIT(2)
+#define DDR_PHY_CKE BIT(1)
+
+#define DDR_PHY_NO_CHANNEL 0xffffffff
+
+#define MAX_NUM_MEMC 3
+
+struct brcmstb_memc {
+ void __iomem *ddr_phy_base;
+ void __iomem *ddr_shimphy_base;
+ void __iomem *ddr_ctrl;
+};
+
+struct brcmstb_pm_control {
+ void __iomem *aon_ctrl_base;
+ void __iomem *aon_sram;
+ struct brcmstb_memc memcs[MAX_NUM_MEMC];
+
+ void __iomem *boot_sram;
+ size_t boot_sram_len;
+
+ bool support_warm_boot;
+ size_t pll_status_offset;
+ int num_memc;
+
+ struct brcmstb_s3_params *s3_params;
+ dma_addr_t s3_params_pa;
+ int s3entry_method;
+ u32 warm_boot_offset;
+ u32 phy_a_standby_ctrl_offs;
+ u32 phy_b_standby_ctrl_offs;
+ bool needs_ddr_pad;
+ struct platform_device *pdev;
+};
+
+enum bsp_initiate_command {
+ BSP_CLOCK_STOP = 0x00,
+ BSP_GEN_RANDOM_KEY = 0x4A,
+ BSP_RESTORE_RANDOM_KEY = 0x55,
+ BSP_GEN_FIXED_KEY = 0x63,
+};
+
+#define PM_INITIATE 0x01
+#define PM_INITIATE_SUCCESS 0x00
+#define PM_INITIATE_FAIL 0xfe
+
+static struct brcmstb_pm_control ctrl;
+
+noinline int brcmstb_pm_s3_finish(void);
+
+static int (*brcmstb_pm_do_s2_sram)(void __iomem *aon_ctrl_base,
+ void __iomem *ddr_phy_pll_status);
+
+static int brcmstb_init_sram(struct device_node *dn)
+{
+ void __iomem *sram;
+ struct resource res;
+ int ret;
+
+ ret = of_address_to_resource(dn, 0, &res);
+ if (ret)
+ return ret;
+
+ /* Uncached, executable remapping of SRAM */
+ sram = __arm_ioremap_exec(res.start, resource_size(&res), false);
+ if (!sram)
+ return -ENOMEM;
+
+ ctrl.boot_sram = sram;
+ ctrl.boot_sram_len = resource_size(&res);
+
+ return 0;
+}
+
+static const struct of_device_id sram_dt_ids[] = {
+ { .compatible = "mmio-sram" },
+ { /* sentinel */ }
+};
+
+static int do_bsp_initiate_command(enum bsp_initiate_command cmd)
+{
+ void __iomem *base = ctrl.aon_ctrl_base;
+ int ret;
+ int timeo = 1000 * 1000; /* 1 second */
+
+ writel_relaxed(0, base + AON_CTRL_PM_INITIATE);
+ (void)readl_relaxed(base + AON_CTRL_PM_INITIATE);
+
+ /* Go! */
+ writel_relaxed((cmd << 1) | PM_INITIATE, base + AON_CTRL_PM_INITIATE);
+
+ /*
+ * If firmware doesn't support the 'ack', then just assume it's done
+ * after 10ms. Note that this only works for command 0, BSP_CLOCK_STOP
+ */
+ if (of_machine_is_compatible("brcm,bcm74371a0")) {
+ (void)readl_relaxed(base + AON_CTRL_PM_INITIATE);
+ mdelay(10);
+ return 0;
+ }
+
+ for (;;) {
+ ret = readl_relaxed(base + AON_CTRL_PM_INITIATE);
+ if (!(ret & PM_INITIATE))
+ break;
+ if (timeo <= 0) {
+ pr_err("error: timeout waiting for BSP (%x)\n", ret);
+ break;
+ }
+ timeo -= 50;
+ udelay(50);
+ }
+
+ return (ret & 0xff) != PM_INITIATE_SUCCESS;
+}
+
+static int brcmstb_pm_handshake(void)
+{
+ void __iomem *base = ctrl.aon_ctrl_base;
+ u32 tmp;
+ int ret;
+
+ /* BSP power handshake, v1 */
+ tmp = readl_relaxed(base + AON_CTRL_HOST_MISC_CMDS);
+ tmp &= ~1UL;
+ writel_relaxed(tmp, base + AON_CTRL_HOST_MISC_CMDS);
+ (void)readl_relaxed(base + AON_CTRL_HOST_MISC_CMDS);
+
+ ret = do_bsp_initiate_command(BSP_CLOCK_STOP);
+ if (ret)
+ pr_err("BSP handshake failed\n");
+
+ /*
+ * HACK: BSP may have internal race on the CLOCK_STOP command.
+ * Avoid touching the BSP for a few milliseconds.
+ */
+ mdelay(3);
+
+ return ret;
+}
+
+static inline void shimphy_set(u32 value, u32 mask)
+{
+ int i;
+
+ if (!ctrl.needs_ddr_pad)
+ return;
+
+ for (i = 0; i < ctrl.num_memc; i++) {
+ u32 tmp;
+
+ tmp = readl_relaxed(ctrl.memcs[i].ddr_shimphy_base +
+ SHIMPHY_DDR_PAD_CNTRL);
+ tmp = value | (tmp & mask);
+ writel_relaxed(tmp, ctrl.memcs[i].ddr_shimphy_base +
+ SHIMPHY_DDR_PAD_CNTRL);
+ }
+ wmb(); /* Complete sequence in order. */
+}
+
+static inline void ddr_ctrl_set(bool warmboot)
+{
+ int i;
+
+ for (i = 0; i < ctrl.num_memc; i++) {
+ u32 tmp;
+
+ tmp = readl_relaxed(ctrl.memcs[i].ddr_ctrl +
+ ctrl.warm_boot_offset);
+ if (warmboot)
+ tmp |= 1;
+ else
+ tmp &= ~1; /* Cold boot */
+ writel_relaxed(tmp, ctrl.memcs[i].ddr_ctrl +
+ ctrl.warm_boot_offset);
+ }
+ /* Complete sequence in order */
+ wmb();
+}
+
+static inline void s3entry_method0(void)
+{
+ shimphy_set(SHIMPHY_PAD_GATE_PLL_S3 | SHIMPHY_PAD_PLL_SEQUENCE,
+ 0xffffffff);
+}
+
+static inline void s3entry_method1(void)
+{
+ /*
+ * S3 Entry Sequence
+ * -----------------
+ * Step 1: SHIMPHY_ADDR_CNTL_0_DDR_PAD_CNTRL [ S3_PWRDWN_SEQ ] = 3
+ * Step 2: MEMC_DDR_0_WARM_BOOT [ WARM_BOOT ] = 1
+ */
+ shimphy_set((PWRDWN_SEQ_POWERDOWN_PLL <<
+ SHIMPHY_PAD_S3_PWRDWN_SEQ_SHIFT),
+ ~SHIMPHY_PAD_S3_PWRDWN_SEQ_MASK);
+
+ ddr_ctrl_set(true);
+}
+
+static inline void s5entry_method1(void)
+{
+ int i;
+
+ /*
+ * S5 Entry Sequence
+ * -----------------
+ * Step 1: SHIMPHY_ADDR_CNTL_0_DDR_PAD_CNTRL [ S3_PWRDWN_SEQ ] = 3
+ * Step 2: MEMC_DDR_0_WARM_BOOT [ WARM_BOOT ] = 0
+ * Step 3: DDR_PHY_CONTROL_REGS_[AB]_0_STANDBY_CONTROL[ CKE ] = 0
+ * DDR_PHY_CONTROL_REGS_[AB]_0_STANDBY_CONTROL[ RST_N ] = 0
+ */
+ shimphy_set((PWRDWN_SEQ_POWERDOWN_PLL <<
+ SHIMPHY_PAD_S3_PWRDWN_SEQ_SHIFT),
+ ~SHIMPHY_PAD_S3_PWRDWN_SEQ_MASK);
+
+ ddr_ctrl_set(false);
+
+ for (i = 0; i < ctrl.num_memc; i++) {
+ u32 tmp;
+
+ /* Step 3: Channel A (RST_N = CKE = 0) */
+ tmp = readl_relaxed(ctrl.memcs[i].ddr_phy_base +
+ ctrl.phy_a_standby_ctrl_offs);
+ tmp &= ~(DDR_PHY_RST_N | DDR_PHY_RST_N);
+ writel_relaxed(tmp, ctrl.memcs[i].ddr_phy_base +
+ ctrl.phy_a_standby_ctrl_offs);
+
+ /* Step 3: Channel B? */
+ if (ctrl.phy_b_standby_ctrl_offs != DDR_PHY_NO_CHANNEL) {
+ tmp = readl_relaxed(ctrl.memcs[i].ddr_phy_base +
+ ctrl.phy_b_standby_ctrl_offs);
+ tmp &= ~(DDR_PHY_RST_N | DDR_PHY_RST_N);
+ writel_relaxed(tmp, ctrl.memcs[i].ddr_phy_base +
+ ctrl.phy_b_standby_ctrl_offs);
+ }
+ }
+ /* Must complete */
+ wmb();
+}
+
+/*
+ * Run a Power Management State Machine (PMSM) shutdown command and put the CPU
+ * into a low-power mode
+ */
+static void brcmstb_do_pmsm_power_down(unsigned long base_cmd, bool onewrite)
+{
+ void __iomem *base = ctrl.aon_ctrl_base;
+
+ if ((ctrl.s3entry_method == 1) && (base_cmd == PM_COLD_CONFIG))
+ s5entry_method1();
+
+ /* pm_start_pwrdn transition 0->1 */
+ writel_relaxed(base_cmd, base + AON_CTRL_PM_CTRL);
+
+ if (!onewrite) {
+ (void)readl_relaxed(base + AON_CTRL_PM_CTRL);
+
+ writel_relaxed(base_cmd | PM_PWR_DOWN, base + AON_CTRL_PM_CTRL);
+ (void)readl_relaxed(base + AON_CTRL_PM_CTRL);
+ }
+ wfi();
+}
+
+/* Support S5 cold boot out of "poweroff" */
+static void brcmstb_pm_poweroff(void)
+{
+ brcmstb_pm_handshake();
+
+ /* Clear magic S3 warm-boot value */
+ writel_relaxed(0, ctrl.aon_sram + AON_REG_MAGIC_FLAGS);
+ (void)readl_relaxed(ctrl.aon_sram + AON_REG_MAGIC_FLAGS);
+
+ /* Skip wait-for-interrupt signal; just use a countdown */
+ writel_relaxed(0x10, ctrl.aon_ctrl_base + AON_CTRL_PM_CPU_WAIT_COUNT);
+ (void)readl_relaxed(ctrl.aon_ctrl_base + AON_CTRL_PM_CPU_WAIT_COUNT);
+
+ if (ctrl.s3entry_method == 1) {
+ shimphy_set((PWRDWN_SEQ_POWERDOWN_PLL <<
+ SHIMPHY_PAD_S3_PWRDWN_SEQ_SHIFT),
+ ~SHIMPHY_PAD_S3_PWRDWN_SEQ_MASK);
+ ddr_ctrl_set(false);
+ brcmstb_do_pmsm_power_down(M1_PM_COLD_CONFIG, true);
+ return; /* We should never actually get here */
+ }
+
+ brcmstb_do_pmsm_power_down(PM_COLD_CONFIG, false);
+}
+
+static void *brcmstb_pm_copy_to_sram(void *fn, size_t len)
+{
+ unsigned int size = ALIGN(len, FNCPY_ALIGN);
+
+ if (ctrl.boot_sram_len < size) {
+ pr_err("standby code will not fit in SRAM\n");
+ return NULL;
+ }
+
+ return fncpy(ctrl.boot_sram, fn, size);
+}
+
+/*
+ * S2 suspend/resume picks up where we left off, so we must execute carefully
+ * from SRAM, in order to allow DDR to come back up safely before we continue.
+ */
+static int brcmstb_pm_s2(void)
+{
+ /* A previous S3 can set a value hazardous to S2, so make sure. */
+ if (ctrl.s3entry_method == 1) {
+ shimphy_set((PWRDWN_SEQ_NO_SEQUENCING <<
+ SHIMPHY_PAD_S3_PWRDWN_SEQ_SHIFT),
+ ~SHIMPHY_PAD_S3_PWRDWN_SEQ_MASK);
+ ddr_ctrl_set(false);
+ }
+
+ brcmstb_pm_do_s2_sram = brcmstb_pm_copy_to_sram(&brcmstb_pm_do_s2,
+ brcmstb_pm_do_s2_sz);
+ if (!brcmstb_pm_do_s2_sram)
+ return -EINVAL;
+
+ return brcmstb_pm_do_s2_sram(ctrl.aon_ctrl_base,
+ ctrl.memcs[0].ddr_phy_base +
+ ctrl.pll_status_offset);
+}
+
+/*
+ * This function is called on a new stack, so don't allow inlining (which will
+ * generate stack references on the old stack). It cannot be made static because
+ * it is referenced from brcmstb_pm_s3()
+ */
+noinline int brcmstb_pm_s3_finish(void)
+{
+ struct brcmstb_s3_params *params = ctrl.s3_params;
+ dma_addr_t params_pa = ctrl.s3_params_pa;
+ phys_addr_t reentry = virt_to_phys(&cpu_resume_arm);
+ enum bsp_initiate_command cmd;
+ u32 flags;
+
+ /*
+ * Clear parameter structure, but not DTU area, which has already been
+ * filled in. We know DTU is a the end, so we can just subtract its
+ * size.
+ */
+ memset(params, 0, sizeof(*params) - sizeof(params->dtu));
+
+ flags = readl_relaxed(ctrl.aon_sram + AON_REG_MAGIC_FLAGS);
+
+ flags &= S3_BOOTLOADER_RESERVED;
+ flags |= S3_FLAG_NO_MEM_VERIFY;
+ flags |= S3_FLAG_LOAD_RANDKEY;
+
+ /* Load random / fixed key */
+ if (flags & S3_FLAG_LOAD_RANDKEY)
+ cmd = BSP_GEN_RANDOM_KEY;
+ else
+ cmd = BSP_GEN_FIXED_KEY;
+ if (do_bsp_initiate_command(cmd)) {
+ pr_info("key loading failed\n");
+ return -EIO;
+ }
+
+ params->magic = BRCMSTB_S3_MAGIC;
+ params->reentry = reentry;
+
+ /* No more writes to DRAM */
+ flush_cache_all();
+
+ flags |= BRCMSTB_S3_MAGIC_SHORT;
+
+ writel_relaxed(flags, ctrl.aon_sram + AON_REG_MAGIC_FLAGS);
+ writel_relaxed(lower_32_bits(params_pa),
+ ctrl.aon_sram + AON_REG_CONTROL_LOW);
+ writel_relaxed(upper_32_bits(params_pa),
+ ctrl.aon_sram + AON_REG_CONTROL_HIGH);
+
+ switch (ctrl.s3entry_method) {
+ case 0:
+ s3entry_method0();
+ brcmstb_do_pmsm_power_down(PM_WARM_CONFIG, false);
+ break;
+ case 1:
+ s3entry_method1();
+ brcmstb_do_pmsm_power_down(M1_PM_WARM_CONFIG, true);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /* Must have been interrupted from wfi()? */
+ return -EINTR;
+}
+
+static int brcmstb_pm_do_s3(unsigned long sp)
+{
+ unsigned long save_sp;
+ int ret;
+
+ asm volatile (
+ "mov %[save], sp\n"
+ "mov sp, %[new]\n"
+ "bl brcmstb_pm_s3_finish\n"
+ "mov %[ret], r0\n"
+ "mov %[new], sp\n"
+ "mov sp, %[save]\n"
+ : [save] "=&r" (save_sp), [ret] "=&r" (ret)
+ : [new] "r" (sp)
+ );
+
+ return ret;
+}
+
+static int brcmstb_pm_s3(void)
+{
+ void __iomem *sp = ctrl.boot_sram + ctrl.boot_sram_len;
+
+ return cpu_suspend((unsigned long)sp, brcmstb_pm_do_s3);
+}
+
+static int brcmstb_pm_standby(bool deep_standby)
+{
+ int ret;
+
+ if (brcmstb_pm_handshake())
+ return -EIO;
+
+ if (deep_standby)
+ ret = brcmstb_pm_s3();
+ else
+ ret = brcmstb_pm_s2();
+ if (ret)
+ pr_err("%s: standby failed\n", __func__);
+
+ return ret;
+}
+
+static int brcmstb_pm_enter(suspend_state_t state)
+{
+ int ret = -EINVAL;
+
+ switch (state) {
+ case PM_SUSPEND_STANDBY:
+ ret = brcmstb_pm_standby(false);
+ break;
+ case PM_SUSPEND_MEM:
+ ret = brcmstb_pm_standby(true);
+ break;
+ }
+
+ return ret;
+}
+
+static int brcmstb_pm_valid(suspend_state_t state)
+{
+ switch (state) {
+ case PM_SUSPEND_STANDBY:
+ return true;
+ case PM_SUSPEND_MEM:
+ return ctrl.support_warm_boot;
+ default:
+ return false;
+ }
+}
+
+static const struct platform_suspend_ops brcmstb_pm_ops = {
+ .enter = brcmstb_pm_enter,
+ .valid = brcmstb_pm_valid,
+};
+
+static const struct of_device_id aon_ctrl_dt_ids[] = {
+ { .compatible = "brcm,brcmstb-aon-ctrl" },
+ {}
+};
+
+struct ddr_phy_ofdata {
+ bool supports_warm_boot;
+ size_t pll_status_offset;
+ int s3entry_method;
+ u32 warm_boot_offset;
+ u32 phy_a_standby_ctrl_offs;
+ u32 phy_b_standby_ctrl_offs;
+};
+
+static struct ddr_phy_ofdata ddr_phy_71_1 = {
+ .supports_warm_boot = true,
+ .pll_status_offset = 0x0c,
+ .s3entry_method = 1,
+ .warm_boot_offset = 0x2c,
+ .phy_a_standby_ctrl_offs = 0x198,
+ .phy_b_standby_ctrl_offs = DDR_PHY_NO_CHANNEL
+};
+
+static struct ddr_phy_ofdata ddr_phy_72_0 = {
+ .supports_warm_boot = true,
+ .pll_status_offset = 0x10,
+ .s3entry_method = 1,
+ .warm_boot_offset = 0x40,
+ .phy_a_standby_ctrl_offs = 0x2a4,
+ .phy_b_standby_ctrl_offs = 0x8a4
+};
+
+static struct ddr_phy_ofdata ddr_phy_225_1 = {
+ .supports_warm_boot = false,
+ .pll_status_offset = 0x4,
+ .s3entry_method = 0
+};
+
+static struct ddr_phy_ofdata ddr_phy_240_1 = {
+ .supports_warm_boot = true,
+ .pll_status_offset = 0x4,
+ .s3entry_method = 0
+};
+
+static const struct of_device_id ddr_phy_dt_ids[] = {
+ {
+ .compatible = "brcm,brcmstb-ddr-phy-v71.1",
+ .data = &ddr_phy_71_1,
+ },
+ {
+ .compatible = "brcm,brcmstb-ddr-phy-v72.0",
+ .data = &ddr_phy_72_0,
+ },
+ {
+ .compatible = "brcm,brcmstb-ddr-phy-v225.1",
+ .data = &ddr_phy_225_1,
+ },
+ {
+ .compatible = "brcm,brcmstb-ddr-phy-v240.1",
+ .data = &ddr_phy_240_1,
+ },
+ {
+ /* Same as v240.1, for the registers we care about */
+ .compatible = "brcm,brcmstb-ddr-phy-v240.2",
+ .data = &ddr_phy_240_1,
+ },
+ {}
+};
+
+struct ddr_seq_ofdata {
+ bool needs_ddr_pad;
+ u32 warm_boot_offset;
+};
+
+static const struct ddr_seq_ofdata ddr_seq_b22 = {
+ .needs_ddr_pad = false,
+ .warm_boot_offset = 0x2c,
+};
+
+static const struct ddr_seq_ofdata ddr_seq = {
+ .needs_ddr_pad = true,
+};
+
+static const struct of_device_id ddr_shimphy_dt_ids[] = {
+ { .compatible = "brcm,brcmstb-ddr-shimphy-v1.0" },
+ {}
+};
+
+static const struct of_device_id brcmstb_memc_of_match[] = {
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.1",
+ .data = &ddr_seq,
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.2",
+ .data = &ddr_seq_b22,
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.3",
+ .data = &ddr_seq_b22,
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.3.0",
+ .data = &ddr_seq_b22,
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.3.1",
+ .data = &ddr_seq_b22,
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr",
+ .data = &ddr_seq,
+ },
+ {},
+};
+
+static void __iomem *brcmstb_ioremap_match(const struct of_device_id *matches,
+ int index, const void **ofdata)
+{
+ struct device_node *dn;
+ const struct of_device_id *match;
+
+ dn = of_find_matching_node_and_match(NULL, matches, &match);
+ if (!dn)
+ return ERR_PTR(-EINVAL);
+
+ if (ofdata)
+ *ofdata = match->data;
+
+ return of_io_request_and_map(dn, index, dn->full_name);
+}
+/*
+ * The AON is a small domain in the SoC that can retain its state across
+ * various system wide sleep states and specific reset conditions; the
+ * AON DATA RAM is a small RAM of a few words (< 1KB) which can store
+ * persistent information across such events.
+ *
+ * The purpose of the below panic notifier is to help with notifying
+ * the bootloader that a panic occurred and so that it should try its
+ * best to preserve the DRAM contents holding that buffer for recovery
+ * by the kernel as opposed to wiping out DRAM clean again.
+ *
+ * Reference: comment from Florian Fainelli, at
+ * https://lore.kernel.org/lkml/781cafb0-8d06-8b56-907a-5175c2da196a@gmail.com
+ */
+static int brcmstb_pm_panic_notify(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ writel_relaxed(BRCMSTB_PANIC_MAGIC, ctrl.aon_sram + AON_REG_PANIC);
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block brcmstb_pm_panic_nb = {
+ .notifier_call = brcmstb_pm_panic_notify,
+};
+
+static int brcmstb_pm_probe(struct platform_device *pdev)
+{
+ const struct ddr_phy_ofdata *ddr_phy_data;
+ const struct ddr_seq_ofdata *ddr_seq_data;
+ const struct of_device_id *of_id = NULL;
+ struct device_node *dn;
+ void __iomem *base;
+ int ret, i, s;
+
+ /* AON ctrl registers */
+ base = brcmstb_ioremap_match(aon_ctrl_dt_ids, 0, NULL);
+ if (IS_ERR(base)) {
+ pr_err("error mapping AON_CTRL\n");
+ ret = PTR_ERR(base);
+ goto aon_err;
+ }
+ ctrl.aon_ctrl_base = base;
+
+ /* AON SRAM registers */
+ base = brcmstb_ioremap_match(aon_ctrl_dt_ids, 1, NULL);
+ if (IS_ERR(base)) {
+ /* Assume standard offset */
+ ctrl.aon_sram = ctrl.aon_ctrl_base +
+ AON_CTRL_SYSTEM_DATA_RAM_OFS;
+ s = 0;
+ } else {
+ ctrl.aon_sram = base;
+ s = 1;
+ }
+
+ writel_relaxed(0, ctrl.aon_sram + AON_REG_PANIC);
+
+ /* DDR PHY registers */
+ base = brcmstb_ioremap_match(ddr_phy_dt_ids, 0,
+ (const void **)&ddr_phy_data);
+ if (IS_ERR(base)) {
+ pr_err("error mapping DDR PHY\n");
+ ret = PTR_ERR(base);
+ goto ddr_phy_err;
+ }
+ ctrl.support_warm_boot = ddr_phy_data->supports_warm_boot;
+ ctrl.pll_status_offset = ddr_phy_data->pll_status_offset;
+ /* Only need DDR PHY 0 for now? */
+ ctrl.memcs[0].ddr_phy_base = base;
+ ctrl.s3entry_method = ddr_phy_data->s3entry_method;
+ ctrl.phy_a_standby_ctrl_offs = ddr_phy_data->phy_a_standby_ctrl_offs;
+ ctrl.phy_b_standby_ctrl_offs = ddr_phy_data->phy_b_standby_ctrl_offs;
+ /*
+ * Slightly gross to use the phy ver to get a memc,
+ * offset but that is the only versioned things so far
+ * we can test for.
+ */
+ ctrl.warm_boot_offset = ddr_phy_data->warm_boot_offset;
+
+ /* DDR SHIM-PHY registers */
+ for_each_matching_node(dn, ddr_shimphy_dt_ids) {
+ i = ctrl.num_memc;
+ if (i >= MAX_NUM_MEMC) {
+ of_node_put(dn);
+ pr_warn("too many MEMCs (max %d)\n", MAX_NUM_MEMC);
+ break;
+ }
+
+ base = of_io_request_and_map(dn, 0, dn->full_name);
+ if (IS_ERR(base)) {
+ of_node_put(dn);
+ if (!ctrl.support_warm_boot)
+ break;
+
+ pr_err("error mapping DDR SHIMPHY %d\n", i);
+ ret = PTR_ERR(base);
+ goto ddr_shimphy_err;
+ }
+ ctrl.memcs[i].ddr_shimphy_base = base;
+ ctrl.num_memc++;
+ }
+
+ /* Sequencer DRAM Param and Control Registers */
+ i = 0;
+ for_each_matching_node(dn, brcmstb_memc_of_match) {
+ base = of_iomap(dn, 0);
+ if (!base) {
+ of_node_put(dn);
+ pr_err("error mapping DDR Sequencer %d\n", i);
+ ret = -ENOMEM;
+ goto brcmstb_memc_err;
+ }
+
+ of_id = of_match_node(brcmstb_memc_of_match, dn);
+ if (!of_id) {
+ iounmap(base);
+ of_node_put(dn);
+ ret = -EINVAL;
+ goto brcmstb_memc_err;
+ }
+
+ ddr_seq_data = of_id->data;
+ ctrl.needs_ddr_pad = ddr_seq_data->needs_ddr_pad;
+ /* Adjust warm boot offset based on the DDR sequencer */
+ if (ddr_seq_data->warm_boot_offset)
+ ctrl.warm_boot_offset = ddr_seq_data->warm_boot_offset;
+
+ ctrl.memcs[i].ddr_ctrl = base;
+ i++;
+ }
+
+ pr_debug("PM: supports warm boot:%d, method:%d, wboffs:%x\n",
+ ctrl.support_warm_boot, ctrl.s3entry_method,
+ ctrl.warm_boot_offset);
+
+ dn = of_find_matching_node(NULL, sram_dt_ids);
+ if (!dn) {
+ pr_err("SRAM not found\n");
+ ret = -EINVAL;
+ goto brcmstb_memc_err;
+ }
+
+ ret = brcmstb_init_sram(dn);
+ of_node_put(dn);
+ if (ret) {
+ pr_err("error setting up SRAM for PM\n");
+ goto brcmstb_memc_err;
+ }
+
+ ctrl.pdev = pdev;
+
+ ctrl.s3_params = kmalloc(sizeof(*ctrl.s3_params), GFP_KERNEL);
+ if (!ctrl.s3_params) {
+ ret = -ENOMEM;
+ goto s3_params_err;
+ }
+ ctrl.s3_params_pa = dma_map_single(&pdev->dev, ctrl.s3_params,
+ sizeof(*ctrl.s3_params),
+ DMA_TO_DEVICE);
+ if (dma_mapping_error(&pdev->dev, ctrl.s3_params_pa)) {
+ pr_err("error mapping DMA memory\n");
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ atomic_notifier_chain_register(&panic_notifier_list,
+ &brcmstb_pm_panic_nb);
+
+ pm_power_off = brcmstb_pm_poweroff;
+ suspend_set_ops(&brcmstb_pm_ops);
+
+ return 0;
+
+out:
+ kfree(ctrl.s3_params);
+s3_params_err:
+ iounmap(ctrl.boot_sram);
+brcmstb_memc_err:
+ for (i--; i >= 0; i--)
+ iounmap(ctrl.memcs[i].ddr_ctrl);
+ddr_shimphy_err:
+ for (i = 0; i < ctrl.num_memc; i++)
+ iounmap(ctrl.memcs[i].ddr_shimphy_base);
+
+ iounmap(ctrl.memcs[0].ddr_phy_base);
+ddr_phy_err:
+ iounmap(ctrl.aon_ctrl_base);
+ if (s)
+ iounmap(ctrl.aon_sram);
+aon_err:
+ pr_warn("PM: initialization failed with code %d\n", ret);
+
+ return ret;
+}
+
+static struct platform_driver brcmstb_pm_driver = {
+ .driver = {
+ .name = "brcmstb-pm",
+ .of_match_table = aon_ctrl_dt_ids,
+ },
+};
+
+static int __init brcmstb_pm_init(void)
+{
+ return platform_driver_probe(&brcmstb_pm_driver,
+ brcmstb_pm_probe);
+}
+module_init(brcmstb_pm_init);