Hi Boris,
On 11/5/18 5:39 PM, Boris Brezillon wrote:
Hi Christophe,
On Fri, 5 Oct 2018 11:41:59 +0200
<christophe.kerello@xxxxxx> wrote:
A few more comments.
+/* Sequencer read/write configuration */
+static void stm32_fmc2_rw_page_init(struct nand_chip *chip, int page,
+ int raw, bool write_data)
+{
+ struct stm32_fmc2 *fmc2 = nand_get_controller_data(chip);
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ u32 csqcfgr1, csqcfgr2, csqcfgr3;
+ u32 csqar1, csqar2;
+ u32 ecc_offset = mtd->writesize + FMC2_BBM_LEN;
+ u32 pcr = readl_relaxed(fmc2->io_base + FMC2_PCR);
+
+ if (write_data)
+ pcr |= FMC2_PCR_WEN;
+ else
+ pcr &= ~FMC2_PCR_WEN;
+ writel_relaxed(pcr, fmc2->io_base + FMC2_PCR);
+
+ /*
+ * - Set Program Page/Page Read command
+ * - Enable DMA request data
+ * - Set timings
+ */
+ csqcfgr1 = FMC2_CSQCFGR1_DMADEN | FMC2_CSQCFGR1_CMD1T;
+ if (write_data)
+ csqcfgr1 |= FMC2_CSQCFGR1_CMD1(NAND_CMD_SEQIN);
+ else
+ csqcfgr1 |= FMC2_CSQCFGR1_CMD1(NAND_CMD_READ0) |
+ FMC2_CSQCFGR1_CMD2EN |
+ FMC2_CSQCFGR1_CMD2(NAND_CMD_READSTART) |
+ FMC2_CSQCFGR1_CMD2T;
+
+ /*
+ * - Set Random Data Input/Random Data Read command
+ * - Enable the sequencer to access the Spare data area
+ * - Enable DMA request status decoding for read
+ * - Set timings
+ */
+ if (write_data)
+ csqcfgr2 = FMC2_CSQCFGR2_RCMD1(NAND_CMD_RNDIN);
+ else
+ csqcfgr2 = FMC2_CSQCFGR2_RCMD1(NAND_CMD_RNDOUT) |
+ FMC2_CSQCFGR2_RCMD2EN |
+ FMC2_CSQCFGR2_RCMD2(NAND_CMD_RNDOUTSTART) |
+ FMC2_CSQCFGR2_RCMD1T |
+ FMC2_CSQCFGR2_RCMD2T;
+ if (!raw) {
+ csqcfgr2 |= write_data ? 0 : FMC2_CSQCFGR2_DMASEN;
+ csqcfgr2 |= FMC2_CSQCFGR2_SQSDTEN;
+ }
+
+ /*
+ * - Set the number of sectors to be written
+ * - Set timings
+ */
+ csqcfgr3 = FMC2_CSQCFGR3_SNBR(chip->ecc.steps - 1);
+ if (write_data) {
+ csqcfgr3 |= FMC2_CSQCFGR3_RAC2T;
+ if (chip->chipsize > SZ_128M)
+ csqcfgr3 |= FMC2_CSQCFGR3_AC5T;
+ else
+ csqcfgr3 |= FMC2_CSQCFGR3_AC4T;
+ }
+
+ /*
+ * Set the fourth first address cycles
+ * Byte 1 and byte 2 => column, we start at 0x0
+ * Byte 3 and byte 4 => page
+ */
+ csqar1 = FMC2_CSQCAR1_ADDC3(page);
+ csqar1 |= FMC2_CSQCAR1_ADDC4(page >> 8);
+
+ /*
+ * - Set chip enable number
+ * - Set ecc byte offset in the spare area
+ * - Calculate the number of address cycles to be issued
+ * - Set byte 5 of address cycle if needed
+ */
+ csqar2 = FMC2_CSQCAR2_NANDCEN(fmc2->cs_sel);
+ if (chip->options & NAND_BUSWIDTH_16)
+ csqar2 |= FMC2_CSQCAR2_SAO(ecc_offset >> 1);
+ else
+ csqar2 |= FMC2_CSQCAR2_SAO(ecc_offset);
+ if (chip->chipsize > SZ_128M) {
Can you use
if (chip->options & NAND_ROW_ADDR_3)
instead?
Yes, it will part of v3.
+ csqcfgr1 |= FMC2_CSQCFGR1_ACYNBR(5);
+ csqar2 |= FMC2_CSQCAR2_ADDC5(page >> 16);
+ } else {
+ csqcfgr1 |= FMC2_CSQCFGR1_ACYNBR(4);
+ }
[...]
+
+void stm32_fmc2_write_data(struct nand_chip *chip, const void *buf,
+ unsigned int len, bool force_8bit)
+{
+ struct stm32_fmc2 *fmc2 = nand_get_controller_data(chip);
+ void __iomem *io_addr_w = fmc2->data_base[fmc2->cs_sel];
+ const u8 *p = buf;
+ unsigned int i;
+
+ if (force_8bit)
+ goto write_8bit;
+
+ if (IS_ALIGNED(len, sizeof(u32))) {
+ const u32 *p = buf;
I'm pretty sure the framework provides no alignment guarantee on buf.
You'd better assume buf might not be aligned on 32 or 16 bits.
+
+ len /= sizeof(u32);
+ for (i = 0; i < len; i++)
+ writel_relaxed(p[i], io_addr_w);
+ return;
+ }
+
+ if (chip->options & NAND_BUSWIDTH_16) {
+ const u16 *p = buf;
+
+ len /= sizeof(u16);
+ for (i = 0; i < len; i++)
+ writew_relaxed(p[i], io_addr_w);
+ return;
+ }
+
+write_8bit:
+ for (i = 0; i < len; i++)
+ writeb_relaxed(p[i], io_addr_w);
Is 8bit access really enforced by the byte accessor? In this case, how
can you be sure 32-bit accesses are doing the right thing? Isn't there
a bit somewhere in the config reg to configure the bus width?
I have checked the framework after Miquèl comment sent on v1 => "If you
selected BOUNCE_BUFFER in the options, buf is supposedly
aligned, or am I missing something?".
After checking the framework, my understanding was:
- In case of 8-bit access is requested, the framework provides no
guarantee on buf. To avoid any issue, I write byte per byte.
- In case of 8-bit access is not requested, it means that the
framework will try to write data in the page or in the oob. When writing
to oob, chip->oob_poi will be used and this buffer is aligned. When
writing to the page, as the driver enables NAND_USE_BOUNCE_BUFFER
option, buf is guarantee aligned.
But, I agree that it would be safe to reconfigure the bus width in 8-bit
before writing byte per byte in case of a 16-bit NAND is used.
write_8bit:
if (chip->options & NAND_BUSWIDTH_16) {
/* Reconfigure bus width to 8-bit */
pcr = readl_relaxed(fmc2->io_base + FMC2_PCR);
pcr &= ~FMC2_PCR_PWID_MASK;
writel_relaxed(pcr, fmc2->io_base + FMC2_PCR);
}
for (i = 0; i < len; i++)
writeb_relaxed(p[i], io_addr_w);
if (chip->options & NAND_BUSWIDTH_16) {
/* Reconfigure bus width to 16-bit */
pcr = readl_relaxed(fmc2->io_base + FMC2_PCR);
pcr |= FMC2_PCR_PWID(FMC2_PCR_PWID_BUSWIDTH_16);
writel_relaxed(pcr, fmc2->io_base + FMC2_PCR);
}
Regards,
Christophe Kerello.
+}
Regards,
Boris
