Hi Philip,
Some early stylistic review comments:
On Sat, Nov 27, 2010 at 11:00:19AM -0800, Philip Rakity wrote:
> Patch made against linux-next (see below) and tested against marvell mmp2
> controller using Marvell linux
The patch doesn't apply against current linux-next or Linus HEAD, due to
Ohad's recent runtime PM change to host.h.
> We define a new MMC_CAP: MMC_CAP_BUS_WIDTH_WORKS that the host adaptation
> layer can set if the controller can support bus width testing.
"BUS_WIDTH_WORKS" is a bit vague. Maybe MMC_CAP_BUS_WIDTH_TEST?
> if ((card->csd.mmca_vsn >= CSD_SPEC_VER_4) &&
> (host->caps & (MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA))) {
> unsigned ext_csd_bit, bus_width;
> + int temp_caps = host->caps & (MMC_CAP_8_BIT_DATA | MMC_CAP_4_BIT_DATA);
>
> - if (host->caps & MMC_CAP_8_BIT_DATA) {
> + do {
> + if (temp_caps & MMC_CAP_8_BIT_DATA) {
> + ext_csd_bit = EXT_CSD_BUS_WIDTH_8;
> + bus_width = MMC_BUS_WIDTH_8;
> + } else {
> + ext_csd_bit = EXT_CSD_BUS_WIDTH_4;
> + bus_width = MMC_BUS_WIDTH_4;
> + }
> +
> + err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> + EXT_CSD_BUS_WIDTH, ext_csd_bit);
> + if (err) {
> + printk(KERN_WARNING "%s: switch to bus width %d ddr %d "
Please stick to 80 cols where possible.
> + "failed\n", mmc_hostname(card->host),
> + 1 << bus_width, ddr);
> + err = 0;
> + } else {
> + mmc_set_bus_width_ddr(card->host, bus_width, MMC_SDR_MODE);
> + /*
> + * if controller can't handle bus width test
> + * try to use the highest bus width to
> + * maintain compatibility with previous linux
> + */
> + if ((host->caps & MMC_CAP_BUS_WIDTH_WORKS) == 0)
> + break;
> + if (mmc_test_bus_width (card, 1<<bus_width))
Extra space here.
> + break;
> + }
> +
> + if (bus_width == MMC_BUS_WIDTH_8)
> + temp_caps &= ~MMC_CAP_8_BIT_DATA;
> + else
> + temp_caps &= ~MMC_CAP_4_BIT_DATA;
> +
> + if (temp_caps == 0) {
> + ext_csd_bit = EXT_CSD_BUS_WIDTH_1;
> + bus_width = MMC_BUS_WIDTH_1;
> + }
> + } while (temp_caps);
> +
> + if (temp_caps == 0) {
> + ext_csd_bit = EXT_CSD_BUS_WIDTH_1;
> + bus_width = MMC_BUS_WIDTH_1;
> + } else if (temp_caps & MMC_CAP_8_BIT_DATA) {
> if (ddr)
> ext_csd_bit = EXT_CSD_DDR_BUS_WIDTH_8;
> else
Why is the "temp_caps == 0" test inside the while loop necessary, rather
than just relying on the same test outside of the loop?
> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
> index 326447c..2b115a3 100644
> --- a/drivers/mmc/core/mmc_ops.c
> +++ b/drivers/mmc/core/mmc_ops.c
> @@ -20,6 +20,138 @@
> #include "core.h"
> #include "mmc_ops.h"
>
> +int mmc_test_bus_width(struct mmc_card *card, int bits)
> +{
> + struct mmc_request mrq;
> + struct mmc_command cmd;
> + struct mmc_data data;
> + struct scatterlist sg;
> + int len;
> + u8 test_data_write[8];
> + u8 test_data_read[64];
> +
> + switch (bits) {
> + case 8:
> + test_data_write[0] = 0x55;
> + test_data_write[1] = 0xaa;
> + test_data_write[2] = 0x00;
> + test_data_write[3] = 0x00;
> + test_data_write[4] = 0x00;
> + test_data_write[5] = 0x00;
> + test_data_write[6] = 0x00;
> + test_data_write[7] = 0x00;
> + len = 8;
> + break;
> + case 4:
> + test_data_write[0] = 0x5a;
> + test_data_write[1] = 0x00;
> + test_data_write[2] = 0x00;
> + test_data_write[3] = 0x00;
> + len = 4;
> + break;
> + default:
> + /* 1 bit bus cards ALWAYS work */
> + return 1;
> + }
> +
> + memset(&mrq, 0, sizeof(struct mmc_request));
> + memset(&cmd, 0, sizeof(struct mmc_command));
> + memset(&data, 0, sizeof(struct mmc_data));
> +
> + cmd.opcode = MMC_BUSTEST_W;
> + cmd.arg = 0;
> +
> + /* NOTE HACK: the MMC_RSP_SPI_R1 is always correct here, but we
> + * rely on callers to never use this with "native" calls for reading
> + * CSD or CID. Native versions of those commands use the R2 type,
> + * not R1 plus a data block.
> + */
> + cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
> +
> + data.flags = MMC_DATA_WRITE;
> + data.blksz = len;
> + data.blocks = 1;
> + data.sg = &sg;
> + data.sg_len = 1;
> +
> + mrq.cmd = &cmd;
> + mrq.data = &data;
> +
> + sg_init_one(&sg, &test_data_write, len);
> +
> + /*
> + * The spec states that MMC_BUSTEST_W and BUSTEST_R accesses
> + * have a maximum timeout of 64 clock cycles.
> + */
> + data.timeout_ns = 0;
> + data.timeout_clks = 64;
> +
> + mmc_wait_for_req(card->host, &mrq);
> +
> + if (cmd.error || data.error ) {
Extra space here.
> + printk(KERN_INFO "%s: Failed to send (BUSTEST_W) CMD19: %d %d\n",
> + mmc_hostname(card->host), cmd.error, data.error);
> + }
> +
> + /* Now read back */
> + memset(&mrq, 0, sizeof(struct mmc_request));
> + memset(&cmd, 0, sizeof(struct mmc_command));
> + memset(&data, 0, sizeof(struct mmc_data));
> + memset (&test_data_read, 0, sizeof(test_data_read));
> +
> + cmd.opcode = MMC_BUSTEST_R;
> + cmd.arg = 0;
> +
> + /* NOTE HACK: the MMC_RSP_SPI_R1 is always correct here, but we
> + * rely on callers to never use this with "native" calls for reading
> + * CSD or CID. Native versions of those commands use the R2 type,
> + * not R1 plus a data block.
> + */
> + cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
> +
> + data.flags = MMC_DATA_READ;
> + data.blksz = len;
> + data.blocks = 1;
> + data.sg = &sg;
> + data.sg_len = 1;
> +
> + mrq.cmd = &cmd;
> + mrq.data = &data;
> +
> + sg_init_one(&sg, &test_data_read, len);
> +
> + data.timeout_ns = 0;
> + data.timeout_clks = 64;
> +
> + mmc_wait_for_req(card->host, &mrq);
> +
> + if (cmd.error) {
> + printk(KERN_INFO "%s: Failed to send CMD14: %d %d\n",
> + mmc_hostname(card->host), cmd.error, data.error);
> + return 0;
> + }
> +
> +#if 0
> +#warning PRINT RESULTS FROM CMD14
> + printk (KERN_INFO "%s: Bits = %d, Got %02X %02X %02X %02X\n", __FUNCTION__,
Extra space, and please don't submit #if 0'd code. You can use a debug
level printk if you want to condition it on CONFIG_MMC_DEBUG. Also,
__func__ instead of __FUNCTION__.
Thanks!
- Chris.
--
Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/>
One Laptop Per Child
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