Hello.
Atsushi Nemoto wrote:
This is the driver for the Toshiba TX4939 SoC ATA controller.
Wow, the first try (by MontaVista) at submitting it was almost 3
years ago! It was hopless back then...
This controller has standard ATA taskfile registers and DMA
command/status registers, but the register layout is swapped on big
endian. There are some other endian issue and some special registers
which requires many custom dma_ops/port_ops routines.
Signed-off-by: Atsushi Nemoto <anemo@xxxxxxxxxxxxx>
I thought that I'd only have the stylyistic comments and ACK the
patch but it shouldn't even compile... :-/
diff --git a/drivers/ide/mips/tx4939ide.c b/drivers/ide/mips/tx4939ide.c
new file mode 100644
index 0000000..e008e1e
--- /dev/null
+++ b/drivers/ide/mips/tx4939ide.c
@@ -0,0 +1,744 @@
+/* ATA Shadow Registers (8bit except for DATA which is 16bit) */
I think "8-bit" and "16-bit" would be more correct...
+#define TX4939IDE_DATA 0x000
+#define TX4939IDE_Error_Ft 0x001
I'd suggest TX4939IDE_Error_Feature -- no point in reducing it when
the full name will fit in the following tab anyway. :-)
+#define TX4939IDE_Sec 0x002
+#define TX4939IDE_LBA0 0x003
+#define TX4939IDE_LBA1 0x004
+#define TX4939IDE_LBA2 0x005
+#define TX4939IDE_Device 0x006
TX4939IDE_DevHead would be more exact.
+#define TX4939IDE_St_Cmd 0x007
+#define TX4939IDE_Alt_DevCtl 0x402
I'd suggest TX4939IDE_Stat_Cmd and TX4939IDE_AltStat_DevCtl...
+/* ATA100 CORE Registers (16bit) */
+#define TX4939IDE_Sys_Ctl 0xc00
+#define TX4939IDE_Xfer_Cnt_1 0xc08
+#define TX4939IDE_Xfer_Cnt_2 0xc0a
+#define TX4939IDE_Sec_Cnt 0xc10
+#define TX4939IDE_Strt_AddL 0xc18
+#define TX4939IDE_Strt_AddU 0xc20
No point in reducing Start too: suggesting
TX4939IDE_Start_{Lo|Up}_Addr -- for consistency with other names.
+#define TX4939IDE_Add_Ctl 0xc28
+#define TX4939IDE_Lo_BCnt 0xc30
+#define TX4939IDE_Up_BCnt 0xc38
TX4939IDE_{Lo|Up}_Burst_Cnt
+#define TX4939IDE_PIO_Acc 0xc88
Suggesting TX4939IDE_PIO_Addr...
+#define TX4939IDE_H_Rst_Tim 0xc90
+#define TX4939IDE_int_ctl 0xc98
+#define TX4939IDE_Pkt_Cmd 0xcb8
+#define TX4939IDE_Bxfer_cntH 0xcc0
+#define TX4939IDE_Bxfer_cntL 0xcc8
Suggesting TX4939IDE_Bxfer_Cnt_{Hi|Lo}...
+#define TX4939IDE_Dev_TErr 0xcd0
+#define TX4939IDE_Pkt_xfer_ct 0xcd8
+#define TX4939IDE_Strt_AddT 0xce0
No point in contracting agaim -- suggesting TX4939IDE_Pkt_Xfer_Ctl
and TX4939IDE_Start_TAddr.
Would have been good to keep the consistent naming style, i.e. either
always have an underscore between name words or only have them after the
TX4939IDE prefix and aways use uppercase to start a word...
+#define TX4939IDE_IGNORE_INTS \
+ (TX4939IDE_INT_ADDRERR | TX4939IDE_INT_REACHMUL | \
+ TX4939IDE_INT_DEVTIMING | TX4939IDE_INT_UDMATERM | \
+ TX4939IDE_INT_TIMER)
Note that interrupt on a bus error that you're ot masking is not
generated by the SFF-8038i compliant controllers as well...
+static void tx4939ide_set_pio_mode(ide_drive_t *drive, const u8 pio)
+{
+ ide_hwif_t *hwif = HWIF(drive);
+ int is_slave = drive->dn & 1;
+ u32 mask, val;
+ u8 safe = pio;
+ ide_drive_t *pair;
+
+ pair = ide_get_pair_dev(drive);
Wait, have you tried to compile this driver? The function is called
ide_get_paired_drive() -- and I did name it correctly in my previous review.
+ if (pair)
+ safe = min(safe, ide_get_best_pio_mode(pair, 255, 4));
+ /*
+ * Update Command Transfer Mode for master/slave and Data
+ * Transfer Mode for this drive.
+ */
+ mask = is_slave ? 0x07f00700 : 0x070007f0;
+ val = (safe << 24) | (safe << 8) | (pio << (is_slave ? 20 : 4));
You are not obliged to set the same command rimings for both drives...
+ hwif->select_data = (hwif->select_data & ~mask) | val;
+ tx4939ide_selectproc(drive);
No dire need to do this as ide_config_drive_speed() will be called
right after the set_pio_mode() method and it will call the selectproc()
method... unless you're dealing with a slow CompactFlash drive.
But actually setting the controller's timings prior to issuing SET
FEATURES doesn't seem safe anyway. Bart, don't you think that we should
always call set_{dma|pio}_mode() AFTER ide_config_drive_speed() --
we have no guarantee that the drive will accept the mode...
+}
+
+static void tx4939ide_set_dma_mode(ide_drive_t *drive, const u8 mode)
+{
+ ide_hwif_t *hwif = HWIF(drive);
+ int is_slave = drive->dn & 1;
It's not that you couldn't do without this variable. :-)
+ u32 mask, val;
+
+ /* Update Data Transfer Mode for this drive. */
+ mask = 0x00f0;
+ if (mode >= XFER_UDMA_0)
+ val = 8 + (mode - XFER_UDMA_0);
+ else if (mode >= XFER_MW_DMA_0)
+ val = 5 + (mode - XFER_MW_DMA_0);
You hardly need parens above...
+ else
+ val = mode - XFER_PIO_0;
+ val <<= 4;
+ if (is_slave) {
+ mask <<= 16;
Could be just:
mask = 0x00f00000;
+ val <<= 16;
+ }
+ hwif->select_data = (hwif->select_data & ~mask) | val;
+ tx4939ide_selectproc(drive);
No dire need to do this as ide_config_drive_speed() will be called
right after the set_dma_mode() method, and it will surely call your
selectproc()...
+static void tx4939ide_check_error_ints(ide_hwif_t *hwif, u16 stat)
+{
Might be worth reading the register right here and returning the
value read in the end.
+ if (stat & TX4939IDE_INT_BUSERR) {
+ void __iomem *base = TX4939IDE_BASE(hwif);
+ /* reset FIFO */
+ tx4939ide_writew(tx4939ide_readw(base, TX4939IDE_Sys_Ctl) |
Probably worth reading the register only once...
+ 0x4000,
+ base, TX4939IDE_Sys_Ctl);
+ /* wait 12GBUSCLK (typ. 60ns @ GBUS200MHz) */
+ ndelay(400);
But why wait 400 ns?
+ tx4939ide_writew(tx4939ide_readw(base, TX4939IDE_Sys_Ctl) &
+ ~0x4000,
+ base, TX4939IDE_Sys_Ctl);
+ }
+ if (stat & (TX4939IDE_INT_ADDRERR | TX4939IDE_INT_REACHMUL |
+ TX4939IDE_INT_DEVTIMING | TX4939IDE_INT_BUSERR))
+ pr_err("%s: Error interrupt %#x (%s%s%s%s )\n",
+ hwif->name, stat,
+ (stat & TX4939IDE_INT_ADDRERR) ?
+ " Address-Error" : "",
+ (stat & TX4939IDE_INT_REACHMUL) ?
+ " Reach-Multiple" : "",
This is not an error condition and should only happen in so called
VDMA mode iff you suspend the transfer, IIUC.
+static void tx4939ide_clear_dma_status(u8 dma_stat, void __iomem *base)
+{
+ /* clear INTR & ERROR flags */
+ tx4939ide_writeb(dma_stat | 6, base, TX4939IDE_DMA_stat);
+ /* recover intmask cleared by writing to bit2 of DMA_stat */
+ tx4939ide_writew(TX4939IDE_IGNORE_INTS << 8, base, TX4939IDE_int_ctl);
+}
What I was suggesting actually was a function that reads the status,
then clears it, and return the status read in the end.
+static int __tx4939ide_dma_setup(ide_drive_t *drive)
+{
+ ide_hwif_t *hwif = drive->hwif;
+ struct request *rq = HWGROUP(drive)->rq;
+ unsigned int reading;
+ u8 dma_stat;
+ void __iomem *base = TX4939IDE_BASE(hwif);
+ int nent;
+
+ if (rq_data_dir(rq))
+ reading = 0;
+ else
+ reading = 1 << 3;
+
+ /* fall back to pio! */
+ nent = ide_build_dmatable(drive, rq);
+ if (!nent) {
+ ide_map_sg(drive, rq);
+ return 1;
+ }
+#ifdef __BIG_ENDIAN
+ {
+ __le64 *table = (__le64 *)hwif->dmatable_cpu;
+
+ while (nent--)
+ le64_to_cpus(table++);
+ }
+#endif
Might be worth reimplementing ide_build_dmatable() for BE mode to
speed it up...
+
+ /* PRD table */
+ tx4939ide_writel(hwif->dmatable_dma, base, TX4939IDE_PRD_Ptr);
+
+ /* specify r/w */
+ tx4939ide_writeb(reading, base, TX4939IDE_DMA_Cmd);
+
+ /* read DMA status for INTR & ERROR flags */
+ dma_stat = tx4939ide_readb(base, TX4939IDE_DMA_stat);
Please fold this call into tx4939ide_clear_dma_status() for mode code
saving...
+ /* clear INTR & ERROR flags */
+ tx4939ide_clear_dma_status(dma_stat, base);
+
+ drive->waiting_for_dma = 1;
+ return 0;
+}
+
+static int tx4939ide_dma_setup(ide_drive_t *drive)
+{
+ ide_hwif_t *hwif = HWIF(drive);
+ void __iomem *base = TX4939IDE_BASE(hwif);
+ int err;
+
+ err = __tx4939ide_dma_setup(drive);
Not sure that you need this function at all...
+static int tx4939ide_dma_end(ide_drive_t *drive)
+{
+ ide_hwif_t *hwif = drive->hwif;
+ u8 dma_stat = 0, dma_cmd = 0;
+ void __iomem *base = TX4939IDE_BASE(hwif);
+ u16 ctl = tx4939ide_readw(base, TX4939IDE_int_ctl);
+
+ drive->waiting_for_dma = 0;
+
+ /* get DMA command mode */
+ dma_cmd = tx4939ide_readb(base, TX4939IDE_DMA_Cmd);
+ /* stop DMA */
+ tx4939ide_writeb(dma_cmd & ~1, base, TX4939IDE_DMA_Cmd);
+
+ /* get DMA status */
+ dma_stat = tx4939ide_readb(base, TX4939IDE_DMA_stat);
Please fold this call into tx4939ide_clear_dma_status().
+/* returns 1 if dma irq issued, 0 otherwise */
+static int tx4939ide_dma_test_irq(ide_drive_t *drive)
+{
+ ide_hwif_t *hwif = HWIF(drive);
+ void __iomem *base = TX4939IDE_BASE(hwif);
+ u16 ctl = tx4939ide_readw(base, TX4939IDE_int_ctl);
+ u8 dma_stat, stat;
+ u16 ide_int;
+ int found = 0;
+
+ tx4939ide_check_error_ints(hwif, ctl);
+ ide_int = ctl & (TX4939IDE_INT_XFEREND | TX4939IDE_INT_HOST);
Well, since you're effectively ignoring the BUSERR interrupt, there's
no point in enabling it...
+ switch (ide_int) {
+ case TX4939IDE_INT_HOST:
+ /* On error, XFEREND might not be asserted. */
+ stat = tx4939ide_readb(base, TX4939IDE_Alt_DevCtl);
+ if ((stat & (ATA_BUSY|ATA_DRQ|ATA_ERR)) == ATA_ERR) {
+ pr_err("%s: detect error %x in %s\n",
+ drive->name, stat, __func__);
This is a normal condition IDE-wise, so no need to emit an error
message. You may emit a warning or info message that the interrupt
workaround is used...
+ found = 1;
+ }
+ /* FALLTHRU */
+ case TX4939IDE_INT_XFEREND:
+ /*
+ * If only one of XFERINT and HOST was asserted
+ * (without error --- see above), mask this interrupt
+ * and wait for an another one. Note that write to
+ * bit2 of DMA_stat will clear all mask bits.
+ */
+ ctl |= ide_int << 8;
+ break;
I'm not sure that we need to *always* unmask XFEREND interrupt. We
only need it after we've received HOST interrupt and decided to wait for
the transfer end.
+ case TX4939IDE_INT_HOST | TX4939IDE_INT_XFEREND:
+ dma_stat = tx4939ide_readb(base, TX4939IDE_DMA_stat);
+ if (!(dma_stat & 4))
+ pr_debug("%s: weird interrupt status. "
This one is worth pr_warning() or even pr_err()...
+ "DMA_stat %#02x int_ctl %#04x\n",
+ hwif->name, dma_stat, ctl);
However, it's already done in the dma_end() method;.do we need
really to print 2 messages?
+static void tx4939ide_init_iops(ide_hwif_t *hwif)
+{
+ /* use extra_base for base address of the all registers */
+ hwif->extra_base = hwif->io_ports.data_addr & ~0xfff;
+}
Ugh... didn't realize that using hwif->extra_base necessiates the
init_iops() method. But why is it necessary? We're not using
hwif->extra_base to access the taskfile.
+static void tx4939ide_init_hwif(ide_hwif_t *hwif)
+{
+ void __iomem *base = TX4939IDE_BASE(hwif);
+
+ /* Soft Reset */
+ tx4939ide_writew(0x8000, base, TX4939IDE_Sys_Ctl);
+ mmiowb();
+ udelay(1); /* at least 20 UPSCLK (100ns for 200MHz GBUSCLK) */
Hm, but your delay is 10x that value...
+static u8 tx4939ide_read_sff_dma_status(ide_hwif_t *hwif)
+{
+ void __iomem *base = TX4939IDE_BASE(hwif);
+ return tx4939ide_readb(base, TX4939IDE_DMA_stat);
+}
Ah, we do use hwif->extra_base in a transport method... well, putting
this into ide_tp_ops was bad move, I have said that already.
+static void tx4939ide_tf_load(ide_drive_t *drive, ide_task_t *task)
+{
+ mm_tf_load(drive, task);
+ if (task->tf_flags & IDE_TFLAG_OUT_DEVICE) {
+ ide_hwif_t *hwif = drive->hwif;
+ void __iomem *base = TX4939IDE_BASE(hwif);
+ /* Fix ATA100 CORE System Control Register */
+ tx4939ide_writew(tx4939ide_readw(base, TX4939IDE_Sys_Ctl) &
+ 0x07f0,
+ base, TX4939IDE_Sys_Ctl);
Why? Doesn't page 17-4 of the datasheet say that these bits get
auto-cleared ona write to the device/head register? Or is this to
address <CAUSION> on page 17-9?
+static const struct ide_tp_ops tx4939ide_tp_ops = {
+ .exec_command = ide_exec_command,
+ .read_status = ide_read_status,
+ .read_altstatus = ide_read_altstatus,
+ .read_sff_dma_status = tx4939ide_read_sff_dma_status,
+
+ .set_irq = ide_set_irq,
+
+ .tf_load = tx4939ide_tf_load,
+ .tf_read = mm_tf_read,
+
+ .input_data = mmio_input_data_swap,
+ .output_data = mmio_output_data_swap,
It would've been more consistent if you used the same function prefix...
+};
+#else /* __LITTLE_ENDIAN */
+static void tx4939ide_tf_load(ide_drive_t *drive, ide_task_t *task)
+{
+ ide_tf_load(drive, task);
+ if (task->tf_flags & IDE_TFLAG_OUT_DEVICE) {
+ ide_hwif_t *hwif = drive->hwif;
+ void __iomem *base = TX4939IDE_BASE(hwif);
+ /* Fix ATA100 CORE System Control Register */
+ tx4939ide_writew(tx4939ide_readw(base, TX4939IDE_Sys_Ctl) &
+ 0x07f0,
+ base, TX4939IDE_Sys_Ctl);
Same question of why this is needed...
+static const struct ide_port_info tx4939ide_port_info __initdata = {
+ .init_iops = tx4939ide_init_iops,
+ .init_hwif = tx4939ide_init_hwif,
+ .init_dma = tx4939ide_init_dma,
+ .port_ops = &tx4939ide_port_ops,
+ .dma_ops = &tx4939ide_dma_ops,
+ .tp_ops = &tx4939ide_tp_ops,
+ .host_flags = IDE_HFLAG_MMIO,
+ .pio_mask = ATA_PIO4,
+ .mwdma_mask = ATA_MWDMA2,
+ .swdma_mask = 0,
No need for explicit zero initializer.
Phew, that was long review...
MBR, Sergei
