[PATCH v10 02/10] mtd: intel-dg: implement region enumeration

[Alexander Usyskin <alexander.usyskin@intel.com>]

In intel-dg, there is no access to the spi controller,
the information is extracted from the descriptor region.

CC: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Co-developed-by: Tomas Winkler <tomasw@gmail.com>
Signed-off-by: Tomas Winkler <tomasw@gmail.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
---
 drivers/mtd/devices/mtd_intel_dg.c | 206 +++++++++++++++++++++++++++++
 1 file changed, 206 insertions(+)

diff --git a/drivers/mtd/devices/mtd_intel_dg.c b/drivers/mtd/devices/mtd_intel_dg.c
index db885929b095..eb16d21e71c7 100644
--- a/drivers/mtd/devices/mtd_intel_dg.c
+++ b/drivers/mtd/devices/mtd_intel_dg.c
@@ -3,6 +3,8 @@
  * Copyright(c) 2019-2025, Intel Corporation. All rights reserved.
  */
 
+#include <linux/bitfield.h>
+#include <linux/bits.h>
 #include <linux/device.h>
 #include <linux/intel_dg_nvm_aux.h>
 #include <linux/io.h>
@@ -22,9 +24,207 @@ struct intel_dg_nvm {
 		u8 id;
 		u64 offset;
 		u64 size;
+		unsigned int is_readable:1;
+		unsigned int is_writable:1;
 	} regions[] __counted_by(nregions);
 };
 
+#define NVM_TRIGGER_REG       0x00000000
+#define NVM_VALSIG_REG        0x00000010
+#define NVM_ADDRESS_REG       0x00000040
+#define NVM_REGION_ID_REG     0x00000044
+/*
+ * [15:0]-Erase size = 0x0010 4K 0x0080 32K 0x0100 64K
+ * [23:16]-Reserved
+ * [31:24]-Erase MEM RegionID
+ */
+#define NVM_ERASE_REG         0x00000048
+#define NVM_ACCESS_ERROR_REG  0x00000070
+#define NVM_ADDRESS_ERROR_REG 0x00000074
+
+/* Flash Valid Signature */
+#define NVM_FLVALSIG          0x0FF0A55A
+
+#define NVM_MAP_ADDR_MASK     GENMASK(7, 0)
+#define NVM_MAP_ADDR_SHIFT    0x00000004
+
+#define NVM_REGION_ID_DESCRIPTOR  0
+/* Flash Region Base Address */
+#define NVM_FRBA      0x40
+/* Flash Region __n - Flash Descriptor Record */
+#define NVM_FLREG(__n) (NVM_FRBA + ((__n) * 4))
+/*  Flash Map 1 Register */
+#define NVM_FLMAP1_REG  0x18
+#define NVM_FLMSTR4_OFFSET 0x00C
+
+#define NVM_ACCESS_ERROR_PCIE_MASK 0x7
+
+#define NVM_FREG_BASE_MASK GENMASK(15, 0)
+#define NVM_FREG_ADDR_MASK GENMASK(31, 16)
+#define NVM_FREG_ADDR_SHIFT 12
+#define NVM_FREG_MIN_REGION_SIZE 0xFFF
+
+static inline void idg_nvm_set_region_id(struct intel_dg_nvm *nvm, u8 region)
+{
+	iowrite32((u32)region, nvm->base + NVM_REGION_ID_REG);
+}
+
+static inline u32 idg_nvm_error(struct intel_dg_nvm *nvm)
+{
+	void __iomem *base = nvm->base;
+
+	u32 reg = ioread32(base + NVM_ACCESS_ERROR_REG) & NVM_ACCESS_ERROR_PCIE_MASK;
+
+	/* reset error bits */
+	if (reg)
+		iowrite32(reg, base + NVM_ACCESS_ERROR_REG);
+
+	return reg;
+}
+
+static inline u32 idg_nvm_read32(struct intel_dg_nvm *nvm, u32 address)
+{
+	void __iomem *base = nvm->base;
+
+	iowrite32(address, base + NVM_ADDRESS_REG);
+
+	return ioread32(base + NVM_TRIGGER_REG);
+}
+
+static int idg_nvm_get_access_map(struct intel_dg_nvm *nvm, u32 *access_map)
+{
+	u32 fmstr4_addr;
+	u32 fmstr4;
+	u32 flmap1;
+	u32 fmba;
+
+	idg_nvm_set_region_id(nvm, NVM_REGION_ID_DESCRIPTOR);
+
+	flmap1 = idg_nvm_read32(nvm, NVM_FLMAP1_REG);
+	if (idg_nvm_error(nvm))
+		return -EIO;
+	/* Get Flash Master Baser Address (FMBA) */
+	fmba = (FIELD_GET(NVM_MAP_ADDR_MASK, flmap1) << NVM_MAP_ADDR_SHIFT);
+	fmstr4_addr = fmba + NVM_FLMSTR4_OFFSET;
+
+	fmstr4 = idg_nvm_read32(nvm, fmstr4_addr);
+	if (idg_nvm_error(nvm))
+		return -EIO;
+
+	*access_map = fmstr4;
+	return 0;
+}
+
+/*
+ * Region read/write access encoded in the access map
+ * in the following order from the lower bit:
+ * [3:0] regions 12-15 read state
+ * [7:4] regions 12-15 write state
+ * [19:8] regions 0-11 read state
+ * [31:20] regions 0-11 write state
+ */
+static bool idg_nvm_region_readable(u32 access_map, u8 region)
+{
+	if (region < 12)
+		return access_map & BIT(region + 8); /* [19:8] */
+	else
+		return access_map & BIT(region - 12); /* [3:0] */
+}
+
+static bool idg_nvm_region_writable(u32 access_map, u8 region)
+{
+	if (region < 12)
+		return access_map & BIT(region + 20); /* [31:20] */
+	else
+		return access_map & BIT(region - 8); /* [7:4] */
+}
+
+static int idg_nvm_is_valid(struct intel_dg_nvm *nvm)
+{
+	u32 is_valid;
+
+	idg_nvm_set_region_id(nvm, NVM_REGION_ID_DESCRIPTOR);
+
+	is_valid = idg_nvm_read32(nvm, NVM_VALSIG_REG);
+	if (idg_nvm_error(nvm))
+		return -EIO;
+
+	if (is_valid != NVM_FLVALSIG)
+		return -ENODEV;
+
+	return 0;
+}
+
+static int intel_dg_nvm_init(struct intel_dg_nvm *nvm, struct device *device)
+{
+	int ret;
+	unsigned int i, n;
+	u32 access_map = 0;
+
+	/* clean error register, previous errors are ignored */
+	idg_nvm_error(nvm);
+
+	ret = idg_nvm_is_valid(nvm);
+	if (ret) {
+		dev_err(device, "The MEM is not valid %d\n", ret);
+		return ret;
+	}
+
+	if (idg_nvm_get_access_map(nvm, &access_map))
+		return -EIO;
+
+	for (i = 0, n = 0; i < nvm->nregions; i++) {
+		u32 address, base, limit, region;
+		u8 id = nvm->regions[i].id;
+
+		address = NVM_FLREG(id);
+		region = idg_nvm_read32(nvm, address);
+
+		base = FIELD_GET(NVM_FREG_BASE_MASK, region) << NVM_FREG_ADDR_SHIFT;
+		limit = (FIELD_GET(NVM_FREG_ADDR_MASK, region) << NVM_FREG_ADDR_SHIFT) |
+			NVM_FREG_MIN_REGION_SIZE;
+
+		dev_dbg(device, "[%d] %s: region: 0x%08X base: 0x%08x limit: 0x%08x\n",
+			id, nvm->regions[i].name, region, base, limit);
+
+		if (base >= limit || (i > 0 && limit == 0)) {
+			dev_dbg(device, "[%d] %s: disabled\n",
+				id, nvm->regions[i].name);
+			nvm->regions[i].is_readable = 0;
+			continue;
+		}
+
+		if (nvm->size < limit)
+			nvm->size = limit;
+
+		nvm->regions[i].offset = base;
+		nvm->regions[i].size = limit - base + 1;
+		/* No write access to descriptor; mask it out*/
+		nvm->regions[i].is_writable = idg_nvm_region_writable(access_map, id);
+
+		nvm->regions[i].is_readable = idg_nvm_region_readable(access_map, id);
+		dev_dbg(device, "Registered, %s id=%d offset=%lld size=%lld rd=%d wr=%d\n",
+			nvm->regions[i].name,
+			nvm->regions[i].id,
+			nvm->regions[i].offset,
+			nvm->regions[i].size,
+			nvm->regions[i].is_readable,
+			nvm->regions[i].is_writable);
+
+		if (nvm->regions[i].is_readable)
+			n++;
+	}
+
+	dev_dbg(device, "Registered %d regions\n", n);
+
+	/* Need to add 1 to the amount of memory
+	 * so it is reported as an even block
+	 */
+	nvm->size += 1;
+
+	return n;
+}
+
 static void intel_dg_nvm_release(struct kref *kref)
 {
 	struct intel_dg_nvm *nvm = container_of(kref, struct intel_dg_nvm, refcnt);
@@ -85,6 +285,12 @@ static int intel_dg_mtd_probe(struct auxiliary_device *aux_dev,
 		goto err;
 	}
 
+	ret = intel_dg_nvm_init(nvm, device);
+	if (ret < 0) {
+		dev_err(device, "cannot initialize nvm %d\n", ret);
+		goto err;
+	}
+
 	dev_set_drvdata(&aux_dev->dev, nvm);
 
 	return 0;
-- 
2.43.0


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