mmc: atmel-mci: add support for odd clock dividers
Add an odd clock divider capability available from v5xx. It also involves changing the clock divider calculation, and changing the switch-case statement to use top-down fallthrough. Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Chris Ball <cjb@laptop.org>
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@ -31,6 +31,7 @@
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# define ATMCI_MR_PDCFBYTE ( 1 << 13) /* Force Byte Transfer */
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# define ATMCI_MR_PDCPADV ( 1 << 14) /* Padding Value */
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# define ATMCI_MR_PDCMODE ( 1 << 15) /* PDC-oriented Mode */
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# define ATMCI_MR_CLKODD(x) ((x) << 16) /* LSB of Clock Divider */
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#define ATMCI_DTOR 0x0008 /* Data Timeout */
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# define ATMCI_DTOCYC(x) ((x) << 0) /* Data Timeout Cycles */
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# define ATMCI_DTOMUL(x) ((x) << 4) /* Data Timeout Multiplier */
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@ -77,6 +77,7 @@ struct atmel_mci_caps {
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bool has_cstor_reg;
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bool has_highspeed;
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bool has_rwproof;
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bool has_odd_clk_div;
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};
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struct atmel_mci_dma {
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@ -1134,16 +1135,27 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
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}
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/* Calculate clock divider */
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clkdiv = DIV_ROUND_UP(host->bus_hz, 2 * clock_min) - 1;
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if (clkdiv > 255) {
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dev_warn(&mmc->class_dev,
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"clock %u too slow; using %lu\n",
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clock_min, host->bus_hz / (2 * 256));
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clkdiv = 255;
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if (host->caps.has_odd_clk_div) {
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clkdiv = DIV_ROUND_UP(host->bus_hz, clock_min) - 2;
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if (clkdiv > 511) {
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dev_warn(&mmc->class_dev,
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"clock %u too slow; using %lu\n",
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clock_min, host->bus_hz / (511 + 2));
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clkdiv = 511;
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}
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host->mode_reg = ATMCI_MR_CLKDIV(clkdiv >> 1)
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| ATMCI_MR_CLKODD(clkdiv & 1);
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} else {
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clkdiv = DIV_ROUND_UP(host->bus_hz, 2 * clock_min) - 1;
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if (clkdiv > 255) {
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dev_warn(&mmc->class_dev,
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"clock %u too slow; using %lu\n",
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clock_min, host->bus_hz / (2 * 256));
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clkdiv = 255;
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}
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host->mode_reg = ATMCI_MR_CLKDIV(clkdiv);
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}
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host->mode_reg = ATMCI_MR_CLKDIV(clkdiv);
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/*
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* WRPROOF and RDPROOF prevent overruns/underruns by
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* stopping the clock when the FIFO is full/empty.
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@ -2014,37 +2026,35 @@ static void __init atmci_get_cap(struct atmel_mci *host)
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"version: 0x%x\n", version);
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host->caps.has_dma = 0;
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host->caps.has_pdc = 0;
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host->caps.has_pdc = 1;
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host->caps.has_cfg_reg = 0;
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host->caps.has_cstor_reg = 0;
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host->caps.has_highspeed = 0;
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host->caps.has_rwproof = 0;
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host->caps.has_odd_clk_div = 0;
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/* keep only major version number */
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switch (version & 0xf00) {
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case 0x100:
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host->caps.has_pdc = 1;
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break;
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case 0x200:
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host->caps.has_pdc = 1;
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host->caps.has_rwproof = 1;
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break;
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case 0x300:
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case 0x400:
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case 0x500:
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host->caps.has_odd_clk_div = 1;
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case 0x400:
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case 0x300:
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#ifdef CONFIG_AT_HDMAC
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host->caps.has_dma = 1;
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#else
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host->caps.has_dma = 0;
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dev_info(&host->pdev->dev,
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"has dma capability but dma engine is not selected, then use pio\n");
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#endif
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host->caps.has_pdc = 0;
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host->caps.has_cfg_reg = 1;
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host->caps.has_cstor_reg = 1;
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host->caps.has_highspeed = 1;
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case 0x200:
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host->caps.has_rwproof = 1;
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case 0x100:
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break;
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default:
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host->caps.has_pdc = 0;
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dev_warn(&host->pdev->dev,
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"Unmanaged mci version, set minimum capabilities\n");
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break;
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