From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
Add support for module reset handling on the RZ/T2H SoC. Unlike earlier
CPG/MSSR variants, RZ/T2H uses a unified set of Module Reset Control
Registers (MRCR) where both reset and deassert actions are done via
read-modify-write (RMW) to the same register.
Introduce a new MRCR offset table (mrcr_for_rzt2h) for RZ/T2H and assign
it to reset_regs. For this SoC, the number of resets is based on the
number of MRCR registers rather than the number of module clocks. Also
add cpg_mrcr_reset_ops to implement reset, assert, and deassert using RMW
while holding the spinlock. This follows the RZ/T2H requirements, where
processing after releasing a module reset must be secured by performing
seven dummy reads of the same register, and where a module that is reset
and released again must ensure the target bit in the Module Reset Control
Register is set to 1.
Update the reset controller registration to select cpg_mrcr_reset_ops for
RZ/T2H, while keeping the existing cpg_mssr_reset_ops for other SoCs.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
---
v2->v3:
- Simplifed the code by adding a common function cpg_mrcr_set_bit() to handle
set/clear of bits with options for verify and dummy reads.
- Added a macro for the number of dummy reads required.
v1->v2:
- Added cpg_mrcr_reset_ops for RZ/T2H specific handling
- Updated commit message
---
drivers/clk/renesas/renesas-cpg-mssr.c | 112 ++++++++++++++++++++++++-
1 file changed, 108 insertions(+), 4 deletions(-)
diff --git a/drivers/clk/renesas/renesas-cpg-mssr.c b/drivers/clk/renesas/renesas-cpg-mssr.c
index 5ff6ee1f7d4b..81206db2b873 100644
--- a/drivers/clk/renesas/renesas-cpg-mssr.c
+++ b/drivers/clk/renesas/renesas-cpg-mssr.c
@@ -40,6 +40,8 @@
#define WARN_DEBUG(x) do { } while (0)
#endif
+#define RZT2H_RESET_REG_READ_COUNT 7
+
/*
* Module Standby and Software Reset register offets.
*
@@ -137,6 +139,22 @@ static const u16 srcr_for_gen4[] = {
0x2C60, 0x2C64, 0x2C68, 0x2C6C, 0x2C70, 0x2C74,
};
+static const u16 mrcr_for_rzt2h[] = {
+ 0x240, /* MRCTLA */
+ 0x244, /* Reserved */
+ 0x248, /* Reserved */
+ 0x24C, /* Reserved */
+ 0x250, /* MRCTLE */
+ 0x254, /* Reserved */
+ 0x258, /* Reserved */
+ 0x25C, /* Reserved */
+ 0x260, /* MRCTLI */
+ 0x264, /* Reserved */
+ 0x268, /* Reserved */
+ 0x26C, /* Reserved */
+ 0x270, /* MRCTLM */
+};
+
/*
* Software Reset Clearing Register offsets
*/
@@ -736,6 +754,73 @@ static int cpg_mssr_status(struct reset_controller_dev *rcdev,
return !!(readl(priv->pub.base0 + priv->reset_regs[reg]) & bitmask);
}
+static int cpg_mrcr_set_bit(struct reset_controller_dev *rcdev, unsigned long id,
+ bool set, bool verify, bool dummy_reads, const char *op_name)
+{
+ struct cpg_mssr_priv *priv = rcdev_to_priv(rcdev);
+ unsigned int reg = id / 32;
+ unsigned int bit = id % 32;
+ u32 bitmask = BIT(bit);
+ void __iomem *reg_addr;
+ unsigned long flags;
+ unsigned int i;
+ u32 val;
+
+ dev_dbg(priv->dev, "%s %u%02u\n", op_name, reg, bit);
+
+ spin_lock_irqsave(&priv->pub.rmw_lock, flags);
+
+ reg_addr = priv->pub.base0 + priv->reset_regs[reg];
+ /* Read current value and modify */
+ val = readl(reg_addr);
+ if (set)
+ val |= bitmask;
+ else
+ val &= ~bitmask;
+ writel(val, reg_addr);
+
+ /* Verify the operation if requested */
+ if (verify) {
+ val = readl(reg_addr);
+ if ((set && !(bitmask & val)) || (!set && (bitmask & val))) {
+ dev_err(priv->dev, "Reset register %u%02u operation failed\n", reg, bit);
+ spin_unlock_irqrestore(&priv->pub.rmw_lock, flags);
+ return -EIO;
+ }
+ }
+
+ /* Perform dummy reads if required */
+ for (i = 0; dummy_reads && i < RZT2H_RESET_REG_READ_COUNT; i++)
+ readl(reg_addr);
+
+ spin_unlock_irqrestore(&priv->pub.rmw_lock, flags);
+
+ return 0;
+}
+
+static int cpg_mrcr_reset(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ int ret;
+
+ /* Assert reset */
+ ret = cpg_mrcr_set_bit(rcdev, id, true, true, false, "reset");
+ if (ret)
+ return ret;
+
+ /* Deassert reset with dummy reads */
+ return cpg_mrcr_set_bit(rcdev, id, false, false, true, "reset");
+}
+
+static int cpg_mrcr_assert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ return cpg_mrcr_set_bit(rcdev, id, true, true, false, "assert");
+}
+
+static int cpg_mrcr_deassert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ return cpg_mrcr_set_bit(rcdev, id, false, false, true, "deassert");
+}
+
static const struct reset_control_ops cpg_mssr_reset_ops = {
.reset = cpg_mssr_reset,
.assert = cpg_mssr_assert,
@@ -743,6 +828,13 @@ static const struct reset_control_ops cpg_mssr_reset_ops = {
.status = cpg_mssr_status,
};
+static const struct reset_control_ops cpg_mrcr_reset_ops = {
+ .reset = cpg_mrcr_reset,
+ .assert = cpg_mrcr_assert,
+ .deassert = cpg_mrcr_deassert,
+ .status = cpg_mssr_status,
+};
+
static int cpg_mssr_reset_xlate(struct reset_controller_dev *rcdev,
const struct of_phandle_args *reset_spec)
{
@@ -760,11 +852,23 @@ static int cpg_mssr_reset_xlate(struct reset_controller_dev *rcdev,
static int cpg_mssr_reset_controller_register(struct cpg_mssr_priv *priv)
{
- priv->rcdev.ops = &cpg_mssr_reset_ops;
+ /*
+ * RZ/T2H (and family) has the Module Reset Control Registers
+ * which allows control resets of certain modules.
+ * The number of resets is not equal to the number of module clocks.
+ */
+ if (priv->reg_layout == CLK_REG_LAYOUT_RZ_T2H) {
+ priv->rcdev.ops = &cpg_mrcr_reset_ops;
+ priv->rcdev.nr_resets = ARRAY_SIZE(mrcr_for_rzt2h) * 32;
+ } else {
+ priv->rcdev.ops = &cpg_mssr_reset_ops;
+ priv->rcdev.nr_resets = priv->num_mod_clks;
+ }
+
priv->rcdev.of_node = priv->dev->of_node;
priv->rcdev.of_reset_n_cells = 1;
priv->rcdev.of_xlate = cpg_mssr_reset_xlate;
- priv->rcdev.nr_resets = priv->num_mod_clks;
+
return devm_reset_controller_register(priv->dev, &priv->rcdev);
}
@@ -1166,6 +1270,7 @@ static int __init cpg_mssr_common_init(struct device *dev,
priv->control_regs = stbcr;
} else if (priv->reg_layout == CLK_REG_LAYOUT_RZ_T2H) {
priv->control_regs = mstpcr_for_rzt2h;
+ priv->reset_regs = mrcr_for_rzt2h;
} else if (priv->reg_layout == CLK_REG_LAYOUT_RCAR_GEN4) {
priv->status_regs = mstpsr_for_gen4;
priv->control_regs = mstpcr_for_gen4;
@@ -1262,8 +1367,7 @@ static int __init cpg_mssr_probe(struct platform_device *pdev)
goto reserve_exit;
/* Reset Controller not supported for Standby Control SoCs */
- if (priv->reg_layout == CLK_REG_LAYOUT_RZ_A ||
- priv->reg_layout == CLK_REG_LAYOUT_RZ_T2H)
+ if (priv->reg_layout == CLK_REG_LAYOUT_RZ_A)
goto reserve_exit;
error = cpg_mssr_reset_controller_register(priv);
--
2.51.0
