--- /dev/null
+From: Felix Fietkau <nbd@nbd.name>
+Date: Thu, 22 Feb 2018 11:11:57 +0100
+Subject: [PATCH] mtd: spi-nor: allow NOR driver to write fewer bytes than
+ requested
+
+The write size can be constrained by the maximum message/transfer size
+of the SPI controller. Only check for ret = 0 to avoid an infinite loop.
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/drivers/mtd/spi-nor/spi-nor.c
++++ b/drivers/mtd/spi-nor/spi-nor.c
+@@ -1371,7 +1371,7 @@ static int spi_nor_write(struct mtd_info
+
+ write_enable(nor);
+ ret = nor->write(nor, addr, page_remain, buf + i);
+- if (ret < 0)
++ if (ret <= 0)
+ goto write_err;
+ written = ret;
+
+@@ -1380,13 +1380,6 @@ static int spi_nor_write(struct mtd_info
+ goto write_err;
+ *retlen += written;
+ i += written;
+- if (written != page_remain) {
+- dev_err(nor->dev,
+- "While writing %zu bytes written %zd bytes\n",
+- page_remain, written);
+- ret = -EIO;
+- goto write_err;
+- }
+ }
+
+ write_err:
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
-@@ -2715,6 +2715,7 @@ int spi_nor_scan(struct spi_nor *nor, co
+@@ -2708,6 +2708,7 @@ int spi_nor_scan(struct spi_nor *nor, co
if (JEDEC_MFR(info) == SNOR_MFR_ATMEL ||
JEDEC_MFR(info) == SNOR_MFR_INTEL ||
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
-@@ -2717,6 +2717,7 @@ int spi_nor_scan(struct spi_nor *nor, co
+@@ -2710,6 +2710,7 @@ int spi_nor_scan(struct spi_nor *nor, co
JEDEC_MFR(info) == SNOR_MFR_INTEL ||
JEDEC_MFR(info) == SNOR_MFR_MACRONIX ||
JEDEC_MFR(info) == SNOR_MFR_SST ||
info->flags & SPI_NOR_HAS_LOCK) {
write_enable(nor);
write_sr(nor, 0);
-@@ -2735,7 +2736,8 @@ int spi_nor_scan(struct spi_nor *nor, co
+@@ -2728,7 +2729,8 @@ int spi_nor_scan(struct spi_nor *nor, co
/* NOR protection support for STmicro/Micron chips and similar */
if (JEDEC_MFR(info) == SNOR_MFR_MICRON ||
depends on ARCH_AT91 || (ARM && COMPILE_TEST)
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
-@@ -2562,10 +2562,12 @@ static int spi_nor_select_erase(struct s
+@@ -2555,10 +2555,12 @@ static int spi_nor_select_erase(struct s
#ifdef CONFIG_MTD_SPI_NOR_USE_4K_SECTORS
/* prefer "small sector" erase if possible */
obj-$(CONFIG_SPI_OC_TINY) += spi-oc-tiny.o
--- /dev/null
+++ b/drivers/spi/spi-mt7621.c
-@@ -0,0 +1,483 @@
+@@ -0,0 +1,491 @@
+/*
+ * spi-mt7621.c -- MediaTek MT7621 SPI controller driver
+ *
+ if (t->speed_hz < speed)
+ speed = t->speed_hz;
+
-+ if (WARN_ON(len + t->len > 36)) {
-+ status = -EIO;
-+ goto msg_done;
-+ }
++ /*
++ * m25p80 might attempt to write more data than we can handle.
++ * truncate the message to what we can fit into the registers
++ */
++ if (len + t->len > 36)
++ t->len = 36 - len;
+
+ for (i = 0; i < t->len; i++, len++)
+ data[len / 4] |= buf[i] << (8 * (len & 3));
+};
+MODULE_DEVICE_TABLE(of, mt7621_spi_match);
+
++static size_t mt7621_max_transfer_size(struct spi_device *spi)
++{
++ return 32;
++}
++
+static int mt7621_spi_probe(struct platform_device *pdev)
+{
+ const struct of_device_id *match;
+ master->bits_per_word_mask = SPI_BPW_MASK(8);
+ master->dev.of_node = pdev->dev.of_node;
+ master->num_chipselect = 2;
++ master->max_transfer_size = mt7621_max_transfer_size;
+
+ dev_set_drvdata(&pdev->dev, master);
+
for (i = 0; i < len; ) {
ssize_t written;
loff_t addr = to + i;
-@@ -1392,6 +1463,7 @@ static int spi_nor_write(struct mtd_info
+@@ -1385,6 +1456,7 @@ static int spi_nor_write(struct mtd_info
}
write_err:
spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_WRITE);
return ret;
}
-@@ -2808,8 +2880,10 @@ int spi_nor_scan(struct spi_nor *nor, co
+@@ -2801,8 +2873,10 @@ int spi_nor_scan(struct spi_nor *nor, co
} else if (mtd->size > 0x1000000) {
/* enable 4-byte addressing if the device exceeds 16MiB */
nor->addr_width = 4;
+++ /dev/null
---- a/drivers/mtd/spi-nor/spi-nor.c
-+++ b/drivers/mtd/spi-nor/spi-nor.c
-@@ -1468,6 +1468,67 @@ write_err:
- return ret;
- }
-
-+static int spi_nor_chunked_write(struct mtd_info *mtd, loff_t _to, size_t _len,
-+ size_t *_retlen, const u_char *_buf)
-+{
-+ struct spi_nor *nor = mtd_to_spi_nor(mtd);
-+ u32 addr_width = nor->addr_width + !!(nor->flags & SNOR_F_4B_EXT_ADDR);
-+ int chunk_size;
-+ int retlen = 0;
-+ int ret;
-+
-+ chunk_size = nor->chunk_size;
-+ if (!chunk_size)
-+ chunk_size = _len;
-+
-+ if (addr_width > 3)
-+ chunk_size -= addr_width - 3;
-+
-+ while (retlen < _len) {
-+ size_t len = min_t(int, chunk_size, _len - retlen);
-+ const u_char *buf = _buf + retlen;
-+ loff_t to = _to + retlen;
-+
-+ if (nor->flags & SNOR_F_SST)
-+ ret = sst_write(mtd, to, len, &retlen, buf);
-+ else
-+ ret = spi_nor_write(mtd, to, len, &retlen, buf);
-+ if (ret)
-+ return ret;
-+ }
-+
-+ *_retlen += retlen;
-+ return 0;
-+}
-+
-+static int spi_nor_chunked_read(struct mtd_info *mtd, loff_t _from, size_t _len,
-+ size_t *_retlen, u_char *_buf)
-+{
-+ struct spi_nor *nor = mtd_to_spi_nor(mtd);
-+ int chunk_size;
-+ int ret;
-+
-+ chunk_size = nor->chunk_size;
-+ if (!chunk_size)
-+ chunk_size = _len;
-+
-+ *_retlen = 0;
-+ while (*_retlen < _len) {
-+ size_t len = min_t(int, chunk_size, _len - *_retlen);
-+ u_char *buf = _buf + *_retlen;
-+ loff_t from = _from + *_retlen;
-+ int retlen = 0;
-+
-+ ret = spi_nor_read(mtd, from, len, &retlen, buf);
-+ if (ret)
-+ return ret;
-+
-+ *_retlen += retlen;
-+ }
-+
-+ return 0;
-+}
-+
- /**
- * macronix_quad_enable() - set QE bit in Status Register.
- * @nor: pointer to a 'struct spi_nor'
-@@ -2826,10 +2887,12 @@ int spi_nor_scan(struct spi_nor *nor, co
- }
-
- /* sst nor chips use AAI word program */
-- if (info->flags & SST_WRITE)
-+ if (info->flags & SST_WRITE) {
- mtd->_write = sst_write;
-- else
-+ nor->flags |= SNOR_F_SST;
-+ } else {
- mtd->_write = spi_nor_write;
-+ }
-
- if (info->flags & USE_FSR)
- nor->flags |= SNOR_F_USE_FSR;
-@@ -2848,11 +2911,20 @@ int spi_nor_scan(struct spi_nor *nor, co
- mtd->writebufsize = nor->page_size;
-
- if (np) {
-+ u32 val;
-+
- /* If we were instantiated by DT, use it */
- if (of_property_read_bool(np, "m25p,fast-read"))
- params.hwcaps.mask |= SNOR_HWCAPS_READ_FAST;
- else
- params.hwcaps.mask &= ~SNOR_HWCAPS_READ_FAST;
-+
-+ if (!of_property_read_u32(np, "m25p,chunked-io", &val)) {
-+ dev_info(dev, "using chunked io (size=%d)\n", val);
-+ mtd->_read = spi_nor_chunked_read;
-+ mtd->_write = spi_nor_chunked_write;
-+ nor->chunk_size = val;
-+ }
- } else {
- /* If we weren't instantiated by DT, default to fast-read */
- params.hwcaps.mask |= SNOR_HWCAPS_READ_FAST;
---- a/include/linux/mtd/spi-nor.h
-+++ b/include/linux/mtd/spi-nor.h
-@@ -231,6 +231,7 @@ enum spi_nor_option_flags {
- SNOR_F_READY_XSR_RDY = BIT(4),
- SNOR_F_USE_CLSR = BIT(5),
- SNOR_F_4B_EXT_ADDR = BIT(6),
-+ SNOR_F_SST = BIT(7),
- };
-
- /**
-@@ -272,6 +273,7 @@ struct spi_nor {
- struct mutex lock;
- struct device *dev;
- u32 page_size;
-+ size_t chunk_size;
- u8 addr_width;
- u8 erase_opcode;
- u8 read_opcode;
{ "mx66u51235f", INFO(0xc2253a, 0, 64 * 1024, 1024, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
{ "mx66l1g45g", INFO(0xc2201b, 0, 64 * 1024, 2048, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
{ "mx66l1g55g", INFO(0xc2261b, 0, 64 * 1024, 2048, SPI_NOR_QUAD_READ) },
-@@ -1947,7 +1947,11 @@ static int spi_nor_read_sfdp(struct spi_
- nor->read_dummy = 8;
-
- while (len) {
-- ret = nor->read(nor, addr, len, (u8 *)buf);
-+ size_t _len = len;
-+
-+ if (nor->chunk_size)
-+ _len = min(len, nor->chunk_size);
-+ ret = nor->read(nor, addr, _len, (u8 *)buf);
- if (!ret || ret > len) {
- ret = -EIO;
- goto read_err;
-@@ -2791,6 +2795,7 @@ int spi_nor_scan(struct spi_nor *nor, co
- struct device *dev = nor->dev;
- struct mtd_info *mtd = &nor->mtd;
- struct device_node *np = spi_nor_get_flash_node(nor);
-+ u32 val;
- int ret;
- int i;
-
-@@ -2803,6 +2808,9 @@ int spi_nor_scan(struct spi_nor *nor, co
- nor->read_proto = SNOR_PROTO_1_1_1;
- nor->write_proto = SNOR_PROTO_1_1_1;
-
-+ if (np && !of_property_read_u32(np, "m25p,chunked-io", &val))
-+ nor->chunk_size = val;
-+
- if (name)
- info = spi_nor_match_id(name);
- /* Try to auto-detect if chip name wasn't specified or not found */
-@@ -2916,19 +2924,16 @@ int spi_nor_scan(struct spi_nor *nor, co
- mtd->writebufsize = nor->page_size;
-
- if (np) {
-- u32 val;
--
- /* If we were instantiated by DT, use it */
- if (of_property_read_bool(np, "m25p,fast-read"))
- params.hwcaps.mask |= SNOR_HWCAPS_READ_FAST;
- else
- params.hwcaps.mask &= ~SNOR_HWCAPS_READ_FAST;
-
-- if (!of_property_read_u32(np, "m25p,chunked-io", &val)) {
-- dev_info(dev, "using chunked io (size=%d)\n", val);
-+ if (nor->chunk_size) {
-+ dev_info(dev, "using chunked io (size=%d)\n", nor->chunk_size);
- mtd->_read = spi_nor_chunked_read;
- mtd->_write = spi_nor_chunked_write;
-- nor->chunk_size = val;
- }
- } else {
- /* If we weren't instantiated by DT, default to fast-read */
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