lib: sbi_irqchip: Support irqchip device targetting subset of harts

It is possible to have platform where an irqchip device targets
a subset of harts and there are multiple irqchip devices to cover
all harts.

To support this scenario:
1) Add target_harts hartmask to struct sbi_irqchip_device which
   represents the set of harts targetted by the irqchip device
2) Call warm_init() and process_hwirqs() callbacks of an irqchip
   device on a hart only if irqchip device targets that particular
   hart

Signed-off-by: Anup Patel <anup.patel@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260213055342.3124872-6-anup.patel@oss.qualcomm.com
Signed-off-by: Anup Patel <anup@brainfault.org>

include/sbi/sbi_irqchip.h

@@ -10,6 +10,7 @@
 #ifndef __SBI_IRQCHIP_H__
 #define __SBI_IRQCHIP_H__
 
+#include <sbi/sbi_hartmask.h>
 #include <sbi/sbi_list.h>
 #include <sbi/sbi_types.h>
 
@@ -20,11 +21,14 @@ struct sbi_irqchip_device {
 	/** Node in the list of irqchip devices */
 	struct sbi_dlist node;
 
+	/** Set of harts targetted by this irqchip */
+	struct sbi_hartmask target_harts;
+
 	/** Initialize per-hart state for the current hart */
 	int (*warm_init)(struct sbi_irqchip_device *chip);
 
 	/** Process hardware interrupts from this irqchip */
-	int (*process_hwirqs)(void);
+	int (*process_hwirqs)(struct sbi_irqchip_device *chip);
 };
 
 /**
@@ -38,7 +42,7 @@ struct sbi_irqchip_device {
 int sbi_irqchip_process(void);
 
 /** Register an irqchip device to receive callbacks */
-void sbi_irqchip_add_device(struct sbi_irqchip_device *chip);
+int sbi_irqchip_add_device(struct sbi_irqchip_device *chip);
 
 /** Initialize interrupt controllers */
 int sbi_irqchip_init(struct sbi_scratch *scratch, bool cold_boot);

lib/sbi/sbi_irqchip.c

@@ -10,36 +10,65 @@
 #include <sbi/sbi_irqchip.h>
 #include <sbi/sbi_list.h>
 #include <sbi/sbi_platform.h>
+#include <sbi/sbi_scratch.h>
 
+struct sbi_irqchip_hart_data {
+	struct sbi_irqchip_device *chip;
+};
+
+static unsigned long irqchip_hart_data_off;
 static SBI_LIST_HEAD(irqchip_list);
 
-static int default_irqfn(void)
-{
-	return SBI_ENODEV;
-}
-
-static int (*ext_irqfn)(void) = default_irqfn;
-
 int sbi_irqchip_process(void)
 {
-	return ext_irqfn();
+	struct sbi_irqchip_hart_data *hd;
+
+	hd = sbi_scratch_thishart_offset_ptr(irqchip_hart_data_off);
+	if (!hd || !hd->chip || !hd->chip->process_hwirqs)
+		return SBI_ENODEV;
+
+	return hd->chip->process_hwirqs(hd->chip);
 }
 
-void sbi_irqchip_add_device(struct sbi_irqchip_device *chip)
+int sbi_irqchip_add_device(struct sbi_irqchip_device *chip)
 {
-	sbi_list_add_tail(&chip->node, &irqchip_list);
+	struct sbi_irqchip_hart_data *hd;
+	struct sbi_scratch *scratch;
+	u32 h;
 
-	if (chip->process_hwirqs)
+	if (!chip || !sbi_hartmask_weight(&chip->target_harts))
-		ext_irqfn = chip->process_hwirqs;
+		return SBI_EINVAL;
+
+	if (chip->process_hwirqs) {
+		sbi_hartmask_for_each_hartindex(h, &chip->target_harts) {
+			scratch = sbi_hartindex_to_scratch(h);
+			if (!scratch)
+				continue;
+
+			hd = sbi_scratch_offset_ptr(scratch, irqchip_hart_data_off);
+			if (hd->chip && hd->chip != chip)
+				return SBI_EINVAL;
+
+			hd->chip = chip;
+		}
+	}
+
+	sbi_list_add_tail(&chip->node, &irqchip_list);
+	return 0;
 }
 
 int sbi_irqchip_init(struct sbi_scratch *scratch, bool cold_boot)
 {
-	int rc;
 	const struct sbi_platform *plat = sbi_platform_ptr(scratch);
+	struct sbi_irqchip_hart_data *hd;
 	struct sbi_irqchip_device *chip;
+	int rc;
 
 	if (cold_boot) {
+		irqchip_hart_data_off =
+			sbi_scratch_alloc_offset(sizeof(struct sbi_irqchip_hart_data));
+		if (!irqchip_hart_data_off)
+			return SBI_ENOMEM;
 		rc = sbi_platform_irqchip_init(plat);
 		if (rc)
 			return rc;
@@ -48,12 +77,15 @@ int sbi_irqchip_init(struct sbi_scratch *scratch, bool cold_boot)
 	sbi_list_for_each_entry(chip, &irqchip_list, node) {
 		if (!chip->warm_init)
 			continue;
+		if (!sbi_hartmask_test_hartindex(current_hartindex(), &chip->target_harts))
+			continue;
 		rc = chip->warm_init(chip);
 		if (rc)
 			return rc;
 	}
 
-	if (ext_irqfn != default_irqfn)
+	hd = sbi_scratch_thishart_offset_ptr(irqchip_hart_data_off);
+	if (hd && hd->chip && hd->chip->process_hwirqs)
 		csr_set(CSR_MIE, MIP_MEIP);
 
 	return 0;
@@ -61,6 +93,9 @@ int sbi_irqchip_init(struct sbi_scratch *scratch, bool cold_boot)
 
 void sbi_irqchip_exit(struct sbi_scratch *scratch)
 {
-	if (ext_irqfn != default_irqfn)
+	struct sbi_irqchip_hart_data *hd;
+
+	hd = sbi_scratch_thishart_offset_ptr(irqchip_hart_data_off);
+	if (hd && hd->chip && hd->chip->process_hwirqs)
 		csr_clear(CSR_MIE, MIP_MEIP);
 }

lib/utils/irqchip/aplic.c

@@ -297,8 +297,18 @@ int aplic_cold_irqchip_init(struct aplic_data *aplic)
 			return rc;
 	}
 
+	if (aplic->num_idc) {
+		for (i = 0; i < aplic->num_idc; i++)
+			sbi_hartmask_set_hartindex(aplic->idc_map[i],
+						   &aplic->irqchip.target_harts);
+	} else {
+		sbi_hartmask_set_all(&aplic->irqchip.target_harts);
+	}
+
 	/* Register irqchip device */
-	sbi_irqchip_add_device(&aplic->irqchip);
+	rc = sbi_irqchip_add_device(&aplic->irqchip);
+	if (rc)
+		return rc;
 
 	/* Attach to the aplic list */
 	sbi_list_add_tail(&aplic->node, &aplic_list);

lib/utils/irqchip/imsic.c

@@ -147,7 +147,7 @@ int imsic_get_target_file(u32 hartindex)
 	return imsic_get_hart_file(scratch);
 }
 
-static int imsic_process_hwirqs(void)
+static int imsic_process_hwirqs(struct sbi_irqchip_device *chip)
 {
 	ulong mirq;
 
@@ -391,7 +391,10 @@ int imsic_cold_irqchip_init(struct imsic_data *imsic)
 	}
 
 	/* Register irqchip device */
-	sbi_irqchip_add_device(&imsic_device);
+	sbi_hartmask_set_all(&imsic_device.target_harts);
+	rc = sbi_irqchip_add_device(&imsic_device);
+	if (rc)
+		return rc;
 
 	/* Register IPI device */
 	sbi_ipi_add_device(&imsic_ipi_device);

lib/utils/irqchip/plic.c

@@ -276,11 +276,10 @@ int plic_cold_irqchip_init(struct plic_data *plic)
 			continue;
 
 		plic_set_hart_data_ptr(sbi_hartindex_to_scratch(i), plic);
+		sbi_hartmask_set_hartindex(i, &plic->irqchip.target_harts);
 	}
 
 	/* Register irqchip device */
 	plic->irqchip.warm_init = plic_warm_irqchip_init;
-	sbi_irqchip_add_device(&plic->irqchip);
+	return sbi_irqchip_add_device(&plic->irqchip);
-
-	return 0;
 }