[PATCH v2 2/2] soc: sifive: ccache: Add StarFive JH7100 support

[Emil Renner Berthing]

From: Emil Renner Berthing <kernel at esmil.dk>

This adds support for the StarFive JH7100 SoC which also features this
SiFive cache controller.

The JH7100 has non-coherent DMAs but predate the standard RISC-V Zicbom
exension, so instead we need to use this cache controller for
non-standard cache management operations.

Unfortunately the interrupt for uncorrected data is broken on the JH7100
and fires continuously, so add a quirk to not register a handler for it.

Signed-off-by: Emil Renner Berthing <kernel at esmil.dk>
---
 drivers/soc/sifive/sifive_ccache.c | 62 +++++++++++++++++++++++++++++-
 1 file changed, 60 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/sifive/sifive_ccache.c b/drivers/soc/sifive/sifive_ccache.c
index 3684f5b40a80..0da3d1bd0866 100644
--- a/drivers/soc/sifive/sifive_ccache.c
+++ b/drivers/soc/sifive/sifive_ccache.c
@@ -8,13 +8,16 @@
 
 #define pr_fmt(fmt) "CCACHE: " fmt
 
+#include <linux/align.h>
 #include <linux/debugfs.h>
 #include <linux/interrupt.h>
 #include <linux/of_irq.h>
 #include <linux/of_address.h>
 #include <linux/device.h>
 #include <linux/bitfield.h>
+#include <asm/cacheflush.h>
 #include <asm/cacheinfo.h>
+#include <asm/dma-noncoherent.h>
 #include <soc/sifive/sifive_ccache.h>
 
 #define SIFIVE_CCACHE_DIRECCFIX_LOW 0x100
@@ -39,10 +42,14 @@
 #define SIFIVE_CCACHE_CONFIG_SETS_MASK GENMASK_ULL(23, 16)
 #define SIFIVE_CCACHE_CONFIG_BLKS_MASK GENMASK_ULL(31, 24)
 
+#define SIFIVE_CCACHE_FLUSH64 0x200
+#define SIFIVE_CCACHE_FLUSH32 0x240
+
 #define SIFIVE_CCACHE_WAYENABLE 0x08
 #define SIFIVE_CCACHE_ECCINJECTERR 0x40
 
 #define SIFIVE_CCACHE_MAX_ECCINTR 4
+#define SIFIVE_CCACHE_LINE_SIZE 64
 
 static void __iomem *ccache_base;
 static int g_irq[SIFIVE_CCACHE_MAX_ECCINTR];
@@ -56,6 +63,11 @@ enum {
 	DIR_UNCORR,
 };
 
+enum {
+	QUIRK_NONSTANDARD_CACHE_OPS	= BIT(0),
+	QUIRK_BROKEN_DATA_UNCORR	= BIT(1),
+};
+
 #ifdef CONFIG_DEBUG_FS
 static struct dentry *sifive_test;
 
@@ -106,6 +118,8 @@ static void ccache_config_read(void)
 static const struct of_device_id sifive_ccache_ids[] = {
 	{ .compatible = "sifive,fu540-c000-ccache" },
 	{ .compatible = "sifive,fu740-c000-ccache" },
+	{ .compatible = "starfive,jh7100-ccache",
+	  .data = (void *)(QUIRK_NONSTANDARD_CACHE_OPS | QUIRK_BROKEN_DATA_UNCORR) },
 	{ .compatible = "sifive,ccache0" },
 	{ /* end of table */ }
 };
@@ -124,6 +138,34 @@ int unregister_sifive_ccache_error_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL_GPL(unregister_sifive_ccache_error_notifier);
 
+#ifdef CONFIG_RISCV_NONSTANDARD_CACHE_OPS
+static void ccache_flush_range(phys_addr_t start, size_t len)
+{
+	phys_addr_t end = start + len;
+	phys_addr_t line;
+
+	if (!len)
+		return;
+
+	mb();
+	for (line = ALIGN_DOWN(start, SIFIVE_CCACHE_LINE_SIZE); line < end;
+			line += SIFIVE_CCACHE_LINE_SIZE) {
+#ifdef CONFIG_32BIT
+		writel(line >> 4, ccache_base + SIFIVE_CCACHE_FLUSH32);
+#else
+		writeq(line, ccache_base + SIFIVE_CCACHE_FLUSH64);
+#endif
+		mb();
+	}
+}
+
+static const struct riscv_nonstd_cache_ops ccache_mgmt_ops __initdata = {
+	.wback = &ccache_flush_range,
+	.inv = &ccache_flush_range,
+	.wback_inv = &ccache_flush_range,
+};
+#endif /* CONFIG_RISCV_NONSTANDARD_CACHE_OPS */
+
 static int ccache_largest_wayenabled(void)
 {
 	return readl(ccache_base + SIFIVE_CCACHE_WAYENABLE) & 0xFF;
@@ -210,11 +252,15 @@ static int __init sifive_ccache_init(void)
 	struct device_node *np;
 	struct resource res;
 	int i, rc, intr_num;
+	const struct of_device_id *match;
+	unsigned long quirks;
 
-	np = of_find_matching_node(NULL, sifive_ccache_ids);
+	np = of_find_matching_node_and_match(NULL, sifive_ccache_ids, &match);
 	if (!np)
 		return -ENODEV;
 
+	quirks = (uintptr_t)match->data;
+
 	if (of_address_to_resource(np, 0, &res)) {
 		rc = -ENODEV;
 		goto err_node_put;
@@ -240,6 +286,10 @@ static int __init sifive_ccache_init(void)
 
 	for (i = 0; i < intr_num; i++) {
 		g_irq[i] = irq_of_parse_and_map(np, i);
+
+		if (i == DATA_UNCORR && (quirks & QUIRK_BROKEN_DATA_UNCORR))
+			continue;
+
 		rc = request_irq(g_irq[i], ccache_int_handler, 0, "ccache_ecc",
 				 NULL);
 		if (rc) {
@@ -249,6 +299,14 @@ static int __init sifive_ccache_init(void)
 	}
 	of_node_put(np);
 
+#ifdef CONFIG_RISCV_NONSTANDARD_CACHE_OPS
+	if (quirks & QUIRK_NONSTANDARD_CACHE_OPS) {
+		riscv_cbom_block_size = SIFIVE_CCACHE_LINE_SIZE;
+		riscv_noncoherent_supported();
+		riscv_noncoherent_register_cache_ops(&ccache_mgmt_ops);
+	}
+#endif
+
 	ccache_config_read();
 
 	ccache_cache_ops.get_priv_group = ccache_get_priv_group;
@@ -269,4 +327,4 @@ static int __init sifive_ccache_init(void)
 	return rc;
 }
 
-device_initcall(sifive_ccache_init);
+arch_initcall(sifive_ccache_init);
-- 
2.40.1