mtd: intel-dg: implement access functions

Implement read(), erase() and write() functions.

CC: Lucas De Marchi <lucas.demarchi@intel.com>
CC: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Raag Jadav <raag.jadav@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>
Co-developed-by: Vitaly Lubart <lubvital@gmail.com>
Signed-off-by: Vitaly Lubart <lubvital@gmail.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Link: https://lore.kernel.org/r/20250617145159.3803852-4-alexander.usyskin@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/mtd/devices/mtd_intel_dg.c

@@ -5,13 +5,16 @@
 
 #include <linux/bitfield.h>
 #include <linux/bits.h>
+#include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/intel_dg_nvm_aux.h>
 #include <linux/io.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/string.h>
 #include <linux/slab.h>
+#include <linux/sizes.h>
 #include <linux/types.h>
 
 struct intel_dg_nvm {
@@ -91,6 +94,33 @@ static inline u32 idg_nvm_read32(struct intel_dg_nvm *nvm, u32 address)
 	return ioread32(base + NVM_TRIGGER_REG);
 }
 
+static inline u64 idg_nvm_read64(struct intel_dg_nvm *nvm, u32 address)
+{
+	void __iomem *base = nvm->base;
+
+	iowrite32(address, base + NVM_ADDRESS_REG);
+
+	return readq(base + NVM_TRIGGER_REG);
+}
+
+static void idg_nvm_write32(struct intel_dg_nvm *nvm, u32 address, u32 data)
+{
+	void __iomem *base = nvm->base;
+
+	iowrite32(address, base + NVM_ADDRESS_REG);
+
+	iowrite32(data, base + NVM_TRIGGER_REG);
+}
+
+static void idg_nvm_write64(struct intel_dg_nvm *nvm, u32 address, u64 data)
+{
+	void __iomem *base = nvm->base;
+
+	iowrite32(address, base + NVM_ADDRESS_REG);
+
+	writeq(data, base + NVM_TRIGGER_REG);
+}
+
 static int idg_nvm_get_access_map(struct intel_dg_nvm *nvm, u32 *access_map)
 {
 	u32 fmstr4_addr;
@@ -155,6 +185,173 @@ static int idg_nvm_is_valid(struct intel_dg_nvm *nvm)
 	return 0;
 }
 
+__maybe_unused
+static unsigned int idg_nvm_get_region(const struct intel_dg_nvm *nvm, loff_t from)
+{
+	unsigned int i;
+
+	for (i = 0; i < nvm->nregions; i++) {
+		if ((nvm->regions[i].offset + nvm->regions[i].size - 1) >= from &&
+		    nvm->regions[i].offset <= from &&
+		    nvm->regions[i].size != 0)
+			break;
+	}
+
+	return i;
+}
+
+static ssize_t idg_nvm_rewrite_partial(struct intel_dg_nvm *nvm, loff_t to,
+				       loff_t offset, size_t len, const u32 *newdata)
+{
+	u32 data = idg_nvm_read32(nvm, to);
+
+	if (idg_nvm_error(nvm))
+		return -EIO;
+
+	memcpy((u8 *)&data + offset, newdata, len);
+
+	idg_nvm_write32(nvm, to, data);
+	if (idg_nvm_error(nvm))
+		return -EIO;
+
+	return len;
+}
+
+__maybe_unused
+static ssize_t idg_write(struct intel_dg_nvm *nvm, u8 region,
+			 loff_t to, size_t len, const unsigned char *buf)
+{
+	size_t len_s = len;
+	size_t to_shift;
+	size_t len8;
+	size_t len4;
+	ssize_t ret;
+	size_t to4;
+	size_t i;
+
+	idg_nvm_set_region_id(nvm, region);
+
+	to4 = ALIGN_DOWN(to, sizeof(u32));
+	to_shift = min(sizeof(u32) - ((size_t)to - to4), len);
+	if (to - to4) {
+		ret = idg_nvm_rewrite_partial(nvm, to4, to - to4, to_shift, (u32 *)&buf[0]);
+		if (ret < 0)
+			return ret;
+
+		buf += to_shift;
+		to += to_shift;
+		len_s -= to_shift;
+	}
+
+	len8 = ALIGN_DOWN(len_s, sizeof(u64));
+	for (i = 0; i < len8; i += sizeof(u64)) {
+		u64 data;
+
+		memcpy(&data, &buf[i], sizeof(u64));
+		idg_nvm_write64(nvm, to + i, data);
+		if (idg_nvm_error(nvm))
+			return -EIO;
+	}
+
+	len4 = len_s - len8;
+	if (len4 >= sizeof(u32)) {
+		u32 data;
+
+		memcpy(&data, &buf[i], sizeof(u32));
+		idg_nvm_write32(nvm, to + i, data);
+		if (idg_nvm_error(nvm))
+			return -EIO;
+		i += sizeof(u32);
+		len4 -= sizeof(u32);
+	}
+
+	if (len4 > 0) {
+		ret = idg_nvm_rewrite_partial(nvm, to + i, 0, len4, (u32 *)&buf[i]);
+		if (ret < 0)
+			return ret;
+	}
+
+	return len;
+}
+
+__maybe_unused
+static ssize_t idg_read(struct intel_dg_nvm *nvm, u8 region,
+			loff_t from, size_t len, unsigned char *buf)
+{
+	size_t len_s = len;
+	size_t from_shift;
+	size_t from4;
+	size_t len8;
+	size_t len4;
+	size_t i;
+
+	idg_nvm_set_region_id(nvm, region);
+
+	from4 = ALIGN_DOWN(from, sizeof(u32));
+	from_shift = min(sizeof(u32) - ((size_t)from - from4), len);
+
+	if (from - from4) {
+		u32 data = idg_nvm_read32(nvm, from4);
+
+		if (idg_nvm_error(nvm))
+			return -EIO;
+		memcpy(&buf[0], (u8 *)&data + (from - from4), from_shift);
+		len_s -= from_shift;
+		buf += from_shift;
+		from += from_shift;
+	}
+
+	len8 = ALIGN_DOWN(len_s, sizeof(u64));
+	for (i = 0; i < len8; i += sizeof(u64)) {
+		u64 data = idg_nvm_read64(nvm, from + i);
+
+		if (idg_nvm_error(nvm))
+			return -EIO;
+
+		memcpy(&buf[i], &data, sizeof(data));
+	}
+
+	len4 = len_s - len8;
+	if (len4 >= sizeof(u32)) {
+		u32 data = idg_nvm_read32(nvm, from + i);
+
+		if (idg_nvm_error(nvm))
+			return -EIO;
+		memcpy(&buf[i], &data, sizeof(data));
+		i += sizeof(u32);
+		len4 -= sizeof(u32);
+	}
+
+	if (len4 > 0) {
+		u32 data = idg_nvm_read32(nvm, from + i);
+
+		if (idg_nvm_error(nvm))
+			return -EIO;
+		memcpy(&buf[i], &data, len4);
+	}
+
+	return len;
+}
+
+__maybe_unused
+static ssize_t
+idg_erase(struct intel_dg_nvm *nvm, u8 region, loff_t from, u64 len, u64 *fail_addr)
+{
+	void __iomem *base = nvm->base;
+	const u32 block = 0x10;
+	u64 i;
+
+	for (i = 0; i < len; i += SZ_4K) {
+		iowrite32(from + i, base + NVM_ADDRESS_REG);
+		iowrite32(region << 24 | block, base + NVM_ERASE_REG);
+		/* Since the writes are via sgunit
+		 * we cannot do back to back erases.
+		 */
+		msleep(50);
+	}
+	return len;
+}
+
 static int intel_dg_nvm_init(struct intel_dg_nvm *nvm, struct device *device)
 {
 	u32 access_map = 0;