On Tuesday, February 04, 2014 at 05:06:14 PM, Jagannadha Sutradharudu Teki wrote:
- Shrink spi_slave {}
- Shrink spi_flash_params {}
- Documentation for sf features
Signed-off-by: Jagannadha Sutradharudu Teki jaganna@xilinx.com
doc/SPI/README.sf-features | 121 +++++++++++++++++++++++++++++ drivers/mtd/spi/sf.c | 4 +- drivers/mtd/spi/sf_internal.h | 1 - drivers/mtd/spi/sf_ops.c | 8 +- drivers/mtd/spi/sf_params.c | 172 +++++++++++++++++++++--------------------- drivers/mtd/spi/sf_probe.c | 71 ++++++++--------- include/spi.h | 42 ++++------- include/spi_flash.h | 34 ++++----- 8 files changed, 272 insertions(+), 181 deletions(-) create mode 100644 doc/SPI/README.sf-features
diff --git a/doc/SPI/README.sf-features b/doc/SPI/README.sf-features new file mode 100644 index 0000000..e203bc0 --- /dev/null +++ b/doc/SPI/README.sf-features @@ -0,0 +1,121 @@ +SPI FLASH feature enhancements: +==============================
You're talking about SPI FLASH and the first thing you describe is struct spi_slave {} ? There should be a foreword about this being deprecated in this MW already and that such "extended" stuff is moving over to dedicated SPI NOR framework.
+This document describes how to extend the current data structures in spi subsystem +for making use of new flash features/operations w.r.t to controller driver support. + +1. spi_slave:
+struct spi_slave {
- ..........
- u32 mode;
- ........
+};
+@mode can be used to expose the SPI RX/TX operation modes, bus options and +few flags which are used to extended the flash specific features/operations +- include/spi.h
+mode: +- SPI_TX_QPP: 4-wire tx transfer
Quad Page Program ... should not ever have anything to do with generic SPI slave. See foreword above ...
+- SPI_RX_SLOW: 1-wire rx transfer +- SPI_RX_DUAL: 2-wire rx transfer +- SPI_RX_DUAL_IO: 2-wire io rx transfer +- SPI_RX_QUAD: 4-wire rx transfer +- SPI_RX_QUAD_IO: 4-wire io rx transfer +- SPI_SHARED: bus shared with two slaves +- SPI_SEPARATED: bus parallel with two slaves +- SPI_U_PAGE: access second slave in bus shared
+2. spi_flash_params:
+struct spi_flash_params {
- ................
- u16 flags;
- ..............
+};
+@flags can be use to verify the flash supported features/operations with respect +to controller driven through @mode and also some internal flash specific +operations - include/spi_flash.h
+flags: +- SST_WP: SST flash write protection +- SECT_4K: 4K erase sector +- SECT_32K: 32 erase sector +- E_FSR: Flag status register for erase/write for micron < 256MB flash +- WR_QPP: Quad page program +- RD_SLOW: Array slow read +- RD_DUAL: Dual fast read +- RD_DUAL_IO: Dual IO read +- RD_QUAD: Quad fast read +- RD_QUAD_IO: Quad IO read +- RD_2WIRE: All 2-wire read commands +- RD_FULL: All read commands +- ALL_CMDS: All read and write commands [1]
+3. spi_flash:
+struct spi_flash {
- ...............
- u8 dual_flash;
u8 shift;- u8 poll_cmd;
u8 erase_cmd;u8 read_cmd;u8 write_cmd;u8 dummy_byte;- ................
Please use spaces and tabs consistently.
+};
+Few varibles from spi_flash {} can be used to perform the internal operations +based on the selected flash features/operations from spi_slave {} and +spi_flash_params {} - include/spi_flash.h
+@dual_flash: flash can be operated in dual flash [2] +@shift: variable shift operator useful for dual parallel +@poll_cmd: find the read_status or flag_status for polling erase/write operations +@erase_cmd: discovered erase command +@read_cmd: discovered read command +@write_cmd: discovered write command +@dummy_byte: read dummy_byte based on read dummy_cycles.
+dummy byte is determined based on the dummy cycles of a particular command. +Fast commands - dummy_byte = dummy_cycles/8 +I/O commands- dummy_byte = (dummy_cycles * no.of lines)/8 +For I/O commands except cmd[0] everything goes on no.of lines based on +particular command but in case of fast commands except data all go on +single line irrespective of command.
+4. Usage:
+In drivers/spi/*.c assign spi_slave {} with supported features through mode. +Ex: drivers/spi/ti_qspi.c
+struct ti_qspi_slave {
- ................
- struct spi_slave slave;
- ..............
+}
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
unsigned int max_hz, unsigned int mode)+{
- .........
- qslave = spi_alloc_slave(struct ti_qspi_slave, bus, cs);
- if (!qslave) {
printf("SPI_error: Fail to allocate ti_qspi_slave\n");return NULL;- }
- qslave->slave.mode = SPI_TX_QPP | SPI_RX_QUAD;
- ........
+}
Sigh, looks like this document instructs people to abuse the SPI framework :-(
You need a BIG FAT WARNING that this was a design mistake here , really.
+[1] http://www.spansion.com/Support/Datasheets/S25FL128S_256S_00.pdf +[2] doc/SPI/README.dual-flash
+-- +Jagannadha Sutradharudu Teki jaganna@xilinx.com +Sat Jan 18 14:44:28 IST 2014 diff --git a/drivers/mtd/spi/sf.c b/drivers/mtd/spi/sf.c index 664e860..b4d7e6c 100644 --- a/drivers/mtd/spi/sf.c +++ b/drivers/mtd/spi/sf.c @@ -19,8 +19,8 @@ static int spi_flash_read_write(struct spi_slave *spi, int ret;
#ifdef CONFIG_SF_DUAL_FLASH
- if (spi->flags & SPI_XFER_U_PAGE)
flags |= SPI_XFER_U_PAGE;
- if (spi->mode & SPI_U_PAGE)
flags |= SPI_U_PAGE;
This change makes no sense, really, you're renaming flag and that's pointless. Please remove this globally.
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