OMAP: hwmod: Add hardreset management support

Most processor IPs does have a hardreset signal controlled by the PRM.
This is different of the softreset used for local IP reset from the
SYSCONFIG register.
The granularity can be much finer than orginal HWMOD, for ex, the IVA
hwmod contains 3 reset lines, the IPU 3 as well, the DSP 2...
Since this granularity is needed by the driver, we have to ensure
than one hwmod exist for each hardreset line.

- Store reset lines as hwmod resources that a driver can query by name like
  an irq or sdma line.

- Add two functions for asserting / deasserting reset lines in hwmods
  processor that require manual reset control.
- Add one functions to get the current reset state.
- If an hwmod contains only one line, an automatic assertion / de-assertion
  is done.
  -> de-assert the hardreset line only during enable from disable transition
  -> assert the hardreset line only during shutdown

Note: The hwmods with hardreset line and HWMOD_INIT_NO_RESET flag must be
kept in INITIALIZED state.
They can be properly enabled only if the hardreset line is de-asserted
before.

For information here is the list of IPs with HW reset control
on an OMAP4430 device:

RM_DSP_RSTCTRL
  1,1,'RST2','RW','1','DSP - MMU, cache and slave interface reset control'
  0,0,'RST1','RW','1','DSP - DSP reset control'

RM_IVA_RSTCTRL
  2,2,'RST3','RW','1','IVA logic and SL2 reset control'
  1,1,'RST2','RW','1','IVA Sequencer2 reset control'
  0,0,'RST1','RW','1','IVA sequencer1 reset control'

RM_IPU_RSTCTRL
  2,2,'RST3','RW','1','IPU MMU and CACHE interface reset control.'
  1,1,'RST2','RW','1','IPU Cortex M3 CPU2  reset control.'
  0,0,'RST1','RW','1','IPU Cortex M3 CPU1  reset control.'

PRM_RSTCTRL
  1,1,'RST_GLOBAL_COLD_SW','RW','0','Global COLD software reset control.'
  0,0,'RST_GLOBAL_WARM_SW','RW','0','Global WARM software reset control.'

RM_CPU0_CPU0_RSTCTRL
RM_CPU1_CPU1_RSTCTRL
  0,0,'RST','RW','0','Cortex A9 CPU0&1 warm local reset control'

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
[paul@pwsan.com: made the hardreset functions static; moved the register
 twiddling into prm*.c functions in previous patches; changed the
 function names to conform with hwmod practice]
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Rajendra Nayak <rnayak@ti.com>

arch/arm/mach-omap2/omap_hwmod.c

@@ -50,11 +50,13 @@
 #include <plat/powerdomain.h>
 #include <plat/clock.h>
 #include <plat/omap_hwmod.h>
+#include <plat/prcm.h>
 
 #include "cm.h"
+#include "prm.h"
 
-/* Maximum microseconds to wait for OMAP module to reset */
-#define MAX_MODULE_RESET_WAIT		10000
+/* Maximum microseconds to wait for OMAP module to softreset */
+#define MAX_MODULE_SOFTRESET_WAIT	10000
 
 /* Name of the OMAP hwmod for the MPU */
 #define MPU_INITIATOR_NAME		"mpu"
@@ -833,6 +835,130 @@ static int _wait_target_ready(struct omap_hwmod *oh)
 	return ret;
 }
 
+/**
+ * _lookup_hardreset - return the register bit shift for this hwmod/reset line
+ * @oh: struct omap_hwmod *
+ * @name: name of the reset line in the context of this hwmod
+ *
+ * Return the bit position of the reset line that match the
+ * input name. Return -ENOENT if not found.
+ */
+static u8 _lookup_hardreset(struct omap_hwmod *oh, const char *name)
+{
+	int i;
+
+	for (i = 0; i < oh->rst_lines_cnt; i++) {
+		const char *rst_line = oh->rst_lines[i].name;
+		if (!strcmp(rst_line, name)) {
+			u8 shift = oh->rst_lines[i].rst_shift;
+			pr_debug("omap_hwmod: %s: _lookup_hardreset: %s: %d\n",
+				 oh->name, rst_line, shift);
+
+			return shift;
+		}
+	}
+
+	return -ENOENT;
+}
+
+/**
+ * _assert_hardreset - assert the HW reset line of submodules
+ * contained in the hwmod module.
+ * @oh: struct omap_hwmod *
+ * @name: name of the reset line to lookup and assert
+ *
+ * Some IP like dsp, ipu or iva contain processor that require
+ * an HW reset line to be assert / deassert in order to enable fully
+ * the IP.
+ */
+static int _assert_hardreset(struct omap_hwmod *oh, const char *name)
+{
+	u8 shift;
+
+	if (!oh)
+		return -EINVAL;
+
+	shift = _lookup_hardreset(oh, name);
+	if (IS_ERR_VALUE(shift))
+		return shift;
+
+	if (cpu_is_omap24xx() || cpu_is_omap34xx())
+		return omap2_prm_assert_hardreset(oh->prcm.omap2.module_offs,
+						  shift);
+	else if (cpu_is_omap44xx())
+		return omap4_prm_assert_hardreset(oh->prcm.omap4.rstctrl_reg,
+						  shift);
+	else
+		return -EINVAL;
+}
+
+/**
+ * _deassert_hardreset - deassert the HW reset line of submodules contained
+ * in the hwmod module.
+ * @oh: struct omap_hwmod *
+ * @name: name of the reset line to look up and deassert
+ *
+ * Some IP like dsp, ipu or iva contain processor that require
+ * an HW reset line to be assert / deassert in order to enable fully
+ * the IP.
+ */
+static int _deassert_hardreset(struct omap_hwmod *oh, const char *name)
+{
+	u8 shift;
+	int r;
+
+	if (!oh)
+		return -EINVAL;
+
+	shift = _lookup_hardreset(oh, name);
+	if (IS_ERR_VALUE(shift))
+		return shift;
+
+	if (cpu_is_omap24xx() || cpu_is_omap34xx())
+		r = omap2_prm_deassert_hardreset(oh->prcm.omap2.module_offs,
+						 shift);
+	else if (cpu_is_omap44xx())
+		r = omap4_prm_deassert_hardreset(oh->prcm.omap4.rstctrl_reg,
+						 shift);
+	else
+		return -EINVAL;
+
+	if (r == -EBUSY)
+		pr_warning("omap_hwmod: %s: failed to hardreset\n", oh->name);
+
+	return r;
+}
+
+/**
+ * _read_hardreset - read the HW reset line state of submodules
+ * contained in the hwmod module
+ * @oh: struct omap_hwmod *
+ * @name: name of the reset line to look up and read
+ *
+ * Return the state of the reset line.
+ */
+static int _read_hardreset(struct omap_hwmod *oh, const char *name)
+{
+	u8 shift;
+
+	if (!oh)
+		return -EINVAL;
+
+	shift = _lookup_hardreset(oh, name);
+	if (IS_ERR_VALUE(shift))
+		return shift;
+
+	if (cpu_is_omap24xx() || cpu_is_omap34xx()) {
+		return omap2_prm_is_hardreset_asserted(oh->prcm.omap2.module_offs,
+						       shift);
+	} else if (cpu_is_omap44xx()) {
+		return omap4_prm_is_hardreset_asserted(oh->prcm.omap4.rstctrl_reg,
+						       shift);
+	} else {
+		return -EINVAL;
+	}
+}
+
 /**
  * _reset - reset an omap_hwmod
  * @oh: struct omap_hwmod *
@@ -869,20 +995,20 @@ static int _reset(struct omap_hwmod *oh)
 
 	omap_test_timeout((omap_hwmod_readl(oh, oh->class->sysc->syss_offs) &
 			   SYSS_RESETDONE_MASK),
-			  MAX_MODULE_RESET_WAIT, c);
+			  MAX_MODULE_SOFTRESET_WAIT, c);
 
-	if (c == MAX_MODULE_RESET_WAIT)
-		WARN(1, "omap_hwmod: %s: failed to reset in %d usec\n",
-		     oh->name, MAX_MODULE_RESET_WAIT);
+	if (c == MAX_MODULE_SOFTRESET_WAIT)
+		WARN(1, "omap_hwmod: %s: softreset failed (waited %d usec)\n",
+		     oh->name, MAX_MODULE_SOFTRESET_WAIT);
 	else
-		pr_debug("omap_hwmod: %s: reset in %d usec\n", oh->name, c);
+		pr_debug("omap_hwmod: %s: softreset in %d usec\n", oh->name, c);
 
 	/*
 	 * XXX add _HWMOD_STATE_WEDGED for modules that don't come back from
 	 * _wait_target_ready() or _reset()
 	 */
 
-	return (c == MAX_MODULE_RESET_WAIT) ? -ETIMEDOUT : 0;
+	return (c == MAX_MODULE_SOFTRESET_WAIT) ? -ETIMEDOUT : 0;
 }
 
 /**
@@ -907,6 +1033,15 @@ int _omap_hwmod_enable(struct omap_hwmod *oh)
 
 	pr_debug("omap_hwmod: %s: enabling\n", oh->name);
 
+	/*
+	 * If an IP contains only one HW reset line, then de-assert it in order
+	 * to allow to enable the clocks. Otherwise the PRCM will return
+	 * Intransition status, and the init will failed.
+	 */
+	if ((oh->_state == _HWMOD_STATE_INITIALIZED ||
+	     oh->_state == _HWMOD_STATE_DISABLED) && oh->rst_lines_cnt == 1)
+		_deassert_hardreset(oh, oh->rst_lines[0].name);
+
 	/* XXX mux balls */
 
 	_add_initiator_dep(oh, mpu_oh);
@@ -981,6 +1116,13 @@ static int _shutdown(struct omap_hwmod *oh)
 	if (oh->class->sysc)
 		_sysc_shutdown(oh);
 
+	/*
+	 * If an IP contains only one HW reset line, then assert it
+	 * before disabling the clocks and shutting down the IP.
+	 */
+	if (oh->rst_lines_cnt == 1)
+		_assert_hardreset(oh, oh->rst_lines[0].name);
+
 	/* clocks and deps are already disabled in idle */
 	if (oh->_state == _HWMOD_STATE_ENABLED) {
 		_del_initiator_dep(oh, mpu_oh);
@@ -1038,6 +1180,16 @@ static int _setup(struct omap_hwmod *oh, void *data)
 	mutex_init(&oh->_mutex);
 	oh->_state = _HWMOD_STATE_INITIALIZED;
 
+	/*
+	 * In the case of hwmod with hardreset that should not be
+	 * de-assert at boot time, we have to keep the module
+	 * initialized, because we cannot enable it properly with the
+	 * reset asserted. Exit without warning because that behavior is
+	 * expected.
+	 */
+	if ((oh->flags & HWMOD_INIT_NO_RESET) && oh->rst_lines_cnt == 1)
+		return 0;
+
 	r = _omap_hwmod_enable(oh);
 	if (r) {
 		pr_warning("omap_hwmod: %s: cannot be enabled (%d)\n",

arch/arm/plat-omap/include/plat/omap_hwmod.h

@@ -108,6 +108,19 @@ struct omap_hwmod_dma_info {
 	u16		dma_req;
 };
 
+/**
+ * struct omap_hwmod_rst_info - IPs reset lines use by hwmod
+ * @name: name of the reset line (module local name)
+ * @rst_shift: Offset of the reset bit
+ *
+ * @name should be something short, e.g., "cpu0" or "rst". It is defined
+ * locally to the hwmod.
+ */
+struct omap_hwmod_rst_info {
+	const char	*name;
+	u8		rst_shift;
+};
+
 /**
  * struct omap_hwmod_opt_clk - optional clocks used by this hwmod
  * @role: "sys", "32k", "tv", etc -- for use in clk_get()
@@ -328,10 +341,12 @@ struct omap_hwmod_omap2_prcm {
 /**
  * struct omap_hwmod_omap4_prcm - OMAP4-specific PRCM data
  * @clkctrl_reg: PRCM address of the clock control register
+ * @rstctrl_reg: adress of the XXX_RSTCTRL register located in the PRM
  * @submodule_wkdep_bit: bit shift of the WKDEP range
  */
 struct omap_hwmod_omap4_prcm {
 	void __iomem	*clkctrl_reg;
+	void __iomem	*rstctrl_reg;
 	u8		submodule_wkdep_bit;
 };
 
@@ -451,6 +466,7 @@ struct omap_hwmod {
 	struct omap_device		*od;
 	struct omap_hwmod_irq_info	*mpu_irqs;
 	struct omap_hwmod_dma_info	*sdma_reqs;
+	struct omap_hwmod_rst_info	*rst_lines;
 	union {
 		struct omap_hwmod_omap2_prcm omap2;
 		struct omap_hwmod_omap4_prcm omap4;
@@ -472,6 +488,7 @@ struct omap_hwmod {
 	u8				response_lat;
 	u8				mpu_irqs_cnt;
 	u8				sdma_reqs_cnt;
+	u8				rst_lines_cnt;
 	u8				opt_clks_cnt;
 	u8				masters_cnt;
 	u8				slaves_cnt;